Michael J. Rainey

Talking to France Via My Electric Razor

2013-04-18T19:44:00.001-07:00

I nearly threw away my worn out Braun 5569 electric shaver a few months ago. On second thought, I decided to at least check it for usable components before I disposed of it. It occurred to me a short while afterwards that it might be fun to attempt to convert whatever was inside it into an amateur radio

I got around to opening it up last week. It was mostly built using surface-mount technology (SMT), but at least it used discrete devices vs. a custom-made IC. A waterproof coating made salvage difficult, but careful surgery with a razor blade allowed me to remove all five SMT transistors and half-a-dozen diodes; one of which was a 5V Zener.

The transistors were soldered to bits of copper-clad "carriers" along with flying leads. One transistor didn't survive the transplant operation. The one non-SMT transistor, an NPN power device, refused to oscillate above 1MHz. The remaining three NPN and one PNP transistors appeared to function well enough at 14MHz that I thought I'd have a go at building something for 20m.

My first idea was to build this Japanese 10/6m DSB rig for 20m using a 14.3MHz computer crystal from my junk box.

After the standard amount of tinkering the transmitter appeared to be operational. Two of the tiny Silicon diodes taken from my electric razor matched well enough to produce a decent carrier null in the single-balanced modulator. I used a pair of NPNs in a push-pull PA stage. A forward-biased diode taken from the razor was used to set the PA bias. The RF CW output was ~90mW. An electret mic from an old telephone drove the PNP SMT transistor in the AF amplifier. The VXO provided a tuning range of 8kHz.

Unfortunately, switching the transmitter to the direct-conversion receiver mode produced the expected result. The 100kW, Nashville-based, WWCR, on 13.845MHz swamped the amateur phone signals. Placing a "balancing" pot in line with the the SBM diodes helped considerably, but not enough to completely eliminate the interference. Past experience tells me that at my QTH a narrow, triple-resonator, BPF is needed between the antenna and these simple diode mixers. I decided to pull the DSB rig apart and build instead a 20m CW station.

I built a 0V1, common-base, Colpitts autodyne regenerative receiver using two of the NPN SMT transistors. The Q-multiplied RF resonator easily shrugs off interference from the high power commercial shortwave transmitter.

The transmitter begins with a variable quartz crystal-controlled oscillator (VXO) made from the third NPN transistor. The final PNP SMT device was used in a common-base, RF power amplifier (PA). The transmitter VXO tunes from 14.055 to 14.061MHz using an xtal cut for the QRP calling frequency. The oscillator free-runs on transmit; only the PA is keyed. The RF output power is 75mW. A 7th order lowpass filter (LPF) holds the harmonics below -45dBc.

The current draw is 1mA on receive and 12mA on transmit using a 9Vdc battery as my power supply.

The bread-boarded transmitter appears in the above photo. The LPF is on the left-hand side, followed by the PA and quartz-crystal oscillator. Two of the transistors taken from the electric razor can be seen in this photo.

Here's a close-up of the two-stage receiver. The regenerative detector is on the left-hand side of the board, followed by one stage of audio amplification. The variable capacitor at the left tunes the receiver from 14.000 to 14.075MHz.

I was pleased to have worked four stations with this setup on April 17, 2013.

W4SX GA 569/339 K2 @5W
KB0PCI MN 569/339 12w
KD4ESO AL 579/559 100w
K5EST MO 569/559 5w

Coming up to the house later in the day I found three Reverse Beacon Network receivers had made captures of my 75mW signal. Oddly enough, all three were located in Europe.

On April 18, I worked three stations; my transmitter still driving an end-fed wire antenna with 75mW of RF power.

N0UR MN 449/229
W4SX GA 579/449
F6DCD France 559/519 K2 @ 5W

F6DCD very kindly called again 35 minutes later to inform me that my signal was still audible near Strasbourg. Denis increased my signal report to 529. Needless to say, I was ecstatic to have "crossed the pond" with the transistors taken from my old electric razor.

On 19 April I received an email from F6DCD

Hello Mike,
I was really pleased to contact you with your 75 mW. I heard you calling on frequency during 1 hour and more. Your sig was really nice on my K2.

Vy 73/72,
Denis, F6DCD

"Sputnik-1" Radio Beacon Schematic Found!

2013-04-09T09:22:00.001-07:00

The search for the schematic diagram of the world's first orbiting radio beacon transmitter is finally over!

Отчет о разработке бортовой радиостанции первого советского искусственного спутника Земли /прибор Д-200/. Репринтное издание. - М.: «ИД Медиа Паблишер»,2012.- 122 с., ISBN 978-5-903650-23-1

Published in 2012, this book is a report on the development of the radio beacon transmitter (D-200) that was carried into orbit by Sputnik 1, on October 4, 1957.

Boris/RU3AX reviewed this book in the April, 2013 edition of the Russian magazine, Radio. His review features the schematic diagram of one of the two radio transmitters carried aboard Sputnik 1. Please click here to open a PDF file of his article.

I would like to thank Oleg/RV3GM and Sergey/UA3ALW for bringing this wonderful news to our attention.

A New Sputnik from the Czech Republic

2013-01-16T18:40:00.001-08:00

OK1DPX, has made a wonderful job of his Sputnik transmitter reproduction. Plug-in modules allow for multi-band operation. He even included an on-board vacuum tube multivibrator (beep-beeper). Petr details his work in the current, Bulletin of the OK QRP Club. Please click here to download his article (presented by permission).

Congratulations and well-done, Petr!

Vacuum Fluorescent QRPp

2012-10-21T12:40:00.000-07:00

I received a Tung-Sol 6977 vacuum fluorescent indicator last week from a friend. Wow...this is the smallest vacuum tube envelope that I've yet seen! The above image of an illuminated 6977 was made by Joe Sousa in this informative post. A quick search for early documentation turned up this 1958 article (pp. 5 to 9 ). Naturally, I wondered whether it might be possible to build a radio from this unusual device.

I used my 6977 to build an 80m regenerative receiver the next day. At first the circuit refused to oscillate, despite having a rather high level of feedback. Temporarily opening the feed-back loop, I noted that it was indeed acting as an RF amplifier. Closing the (positive) feed-back loop again increased the gain, as expected. Obviously, the loop-gain was below unity. Increasing the grid-leak resistor value from 3.9 to 10MegOhms did the trick; adjusting the regeneration control (see schematic) now allowed the receiver to slide smoothly in and out of oscillation. The receiver tunes from 3500 to 3583kHz. I spent the remainder of the evening logging DX stations at the low-end of the 80m CW band.

The next morning I experimented with an 80m, crystal-controlled, Miller oscillator using my 6977. Working to maximize the RF output, I eventually measured slightly more than 1mW across a 50 Ohm load resistor. Given the 57Vdc anode supply at 320uA, this represents a dismal (~6%) RF output/DC input power efficiency.

The anode to antenna impedance matching network is to blame. If the efficiency were a more typical value (say, 25 to 30%), I should expect to measure 5mW of RF output power. In this case, the standard rule-of-thumb formula indicates the anode should be presented with a load impedance of (57^2)/(2*0.005) = 325kOhms.

The most suitable output tank inductor in my junkbox was a "Hescho"-type (14.7uH, Qu ~250) ceramic/silver unit that I picked up at the hamfest in Friedricheshafen. The unloaded equivalent parallel resistance of the resulting output tank resonator is (250*2*Pi*3.5^6*14.7^-6) = 80.8kOhms. This is too low to efficiently produce the required impedance transformation.

The physics of this matching network also implies the tuning will be very sharp. On the other hand, harmonic energy is attenuated quite handily. In fact the second (and worst) harmonic is down by 43dBc, so at least no further spectral filtering is required.

It would be interesting to try a crystal-controlled Colpitts oscillator configuration (raising the filaments up from RF ground via an RFC). Taking the RF output at the filaments ought to ease the required impedance step-down ratio somewhat.

Vacuum Fluorescent QRPp

Component List

X1: 80m quartz crystal
V:1: 6977/DM160 vacuum fluorescent indicator triode
R1: 100k
R2: 10MegOhms
C1: 20nF
C2: 2.5nF s.m.
C3: 5pF s.m.
C4: 360pF s.m.
C5: 40pF s.m.
C6: 100pF s.m.
C7: 3.9nF
C8: 100uF @ 100V
CV1: 20-335pF air-variable
CV2: 15-420pF air-variable
CV3: 30-360pF air-variable
L1: 14.7uH, high Qu (>250)
L2: 3.3mH
T1: 3.5 to 6uH, slug-tuned "IF can"
T2: audio transformer, 13.2kOhms to 600 Ohms
RY1: DPDT "DIP" relay, 12V coil
D1: 1N4148, 1N4002, etc.

I decided to build a transmitter/receiver by relay-switching the grid and the anode of a single 6977 triode between the receiver and transmitter circuits. This worked out quite well. As I often do with my regenerative receiver/quartz-crystal transmitter pairs, transmit frequency spotting is accomplished by listening for a tiny "blip" or "ping" in the headphones as one tunes through the series-resonant frequency of the crystal.

When everything was ready to go, I ran up to the house to post a note on the QRP-L mail reflector with the details of my intended operation. Once on the air it became apparent that it wasn't a good night for milliwatt work; the high QRN was simply masking my signal.

Nevertheless, I called CQ for several hours. Sometime after I'd resigned myself to the fact that I wouldn't make a contact, there was W1PID calling me! Jim remarked on the QRN, but he also handed me a 449 report. He was a perfect copy on the regenerative set; I called it a 579. What fun! Working a station 112km distant with 1mW through heavy 80m QRN augers for "big DX" come the quiet winter months.

I made a short video of my Vacuum Fluorescent rig shortly after my QSO with W1PID.

Link: MØAYF, builds regenerative receivers from surplus VFD's. Well done, Des!

73/72,
Mike, AA1TJ

Simplicity's Reward

2012-07-13T08:47:00.001-07:00

On July 9, I answered a CQ from KB8BWE using my Vanguard 1 station setup. Charlie came back to me straight-away with a 529 report. Unfortunately, my signal subsequently dropped into the noise. While it didn't qualify as a full-fledged QSO, nevertheless, I was pleased to learn that he was operating with three watts into a three-foot diameter loop antenna. The full details of his station arrived in his follow-up email

"...I was using a 3’ diameter magnetic loop called the “Alexloop Walkham” from here:

http://www.alexloop.com/index.html#buy

The loop itself is a piece of RG213 coax. I had just received it in the mail that morning, and was trying it out on the deck behind my house. It all folds up into a laptop-sized case.

The rig is a TenTec 4040 (Youkits HB-1B) 4-band QRP rig that I got at Dayton this year."

I have, these past twenty-five years, worked and lived atop Mt. Mansfield; Vermont's highest peak. My task there is to maintain a powerful commercial television transmitter that is coupled to a huge antenna. For all of that, it might seem curious that having my 25mW signal copied by a guy sitting on his deck in Ohio with a 3' loop antenna would be the thing to send a chill up my spine. In fact, my passion for radio minimalism has long since spoiled me for anything else. :-)

"Simplicity is the final achievement. After one has played a vast quantity of notes and more notes, it is simplicity that emerges as the crowning reward of art." Frédéric Chopin

Vanguard 1 Satellite Transmitter Reproduction

2012-06-30T13:17:00.000-07:00

Last week I aired a reproduction of the Vanguard 1 (TV-4 or "Test Vehicle 4") satellite beacon transmitter on the 20m CW band. The original 6.4" diameter satellite (Premiere Khrushchev famously referred to it as "the grapefruit satellite") carried two, one-transistor "Minitrack" beacon transmitters. One transmitter was powered by seven mercury cells and produced an RF output power of 10mW on 108MHz. The second transmitter produced 5mW on 108.03MHz from energy provided by a small photovoltaic array.

Philco surface-barrier transistors were used in the early beacon prototypes. However, diffused-base PNP germanium transistors produced by Western Electric were found to be more reliable when thermally and vibrationally stressed. The engineers eventually settled on a GA53233 for the battery transmitter. The solar-powered transmitter was equipped with a WE45011. An early Minitrack beacon transmitter prototype using a Philco SBDT-12 surface-barrier transistor provided an output of 10mw with an RF output power/DC input power efficiency of 20%. The same transmitter equipped with a GA53233 transistor produced an identical RF output power at 30% efficiency.

The original circuit operated on the 5th quartz-crystal overtone, whereas my version works on the fundamental resonant frequency. Otherwise, I've tried to reproduce the circuit as faithfully as possible. My reproduction sports a Philco 2N504 MADT (surface-barrier transistor) manufactured in September of 1959. It produces 25mW with an efficiency of 38%. The -8.4Vdc collector supply line is keyed to provide CW transmissions. My antenna is a 44m end-fed wire, supported at a height of 10m.

The two left-hand photos shown below appeared in the May, 1959 edition of CQ Magazine. The article was written by Don Stoner, W6TNS (SK), as part of his regularly featured, "Semiconductors" series. The circuit of my reproduction appears on the right. The output signal connection shown in the CQ Magazine schematic appears to lack a proper impedance match to 50 Ohms. To this end I settled on a simple capacitor divider network. The article expresses a hope that the solar powered beacon would continue to function for several hundred years. In fact it expired after 75 months of operation.

My component values

L1: 10uH molded RFC
L2: 470uH molded RFC
R1 220 Ohms
C1, C2: 10nF
C3: 15pF silver mica
C4: 75pF silver mica
C5: 300pF silver mica
T1: 13 turns on slug-tuned, 5mm dia. former; 2 turn coupling
X1: 14.060MHz quartz crystal
Q1: Philco 2N504, date-code 5937 (September 1959)

The schematic shown below was taken from a Jet Propulsion Laboratory report dated September 6, 1960, and titled, "Juno Final Report: Re-entry Test Vehicles and Explorer Satellites." The text for this figure reads, "The beacon transmitter as flown in early rounds is shown schematically in Fig. 25. Power measurements from the actual flight configuration shows that all the beacons radiate approximately 10mW."

The circuit shown above is very similar to the schematic illustrated in W6TNS's 1959 CQ Magazine article.

Here's a photograph of my bread-boarded transmitter. Please note the early, "silver-bullet," Philco transistor package. The transmit/receive antenna changeover and receiver muting functions are provided by the green DPDT relay along with the time-delay circuitry at the right of the relay. A Pico Keyer appears in the top-left of this photo.

My 0V0 regenerative receiver, built from a single subminiature Raytheon QF721 pentode, is shown below. The illuminated filament shows up clearly in this photo.

W4OP was first to notice my unannounced presence on the 20m QRP calling frequency. Dale emailed after our QSO.

Hi Michael,
That was fun! I first heard you on my SG-2020 rig, but did not have a paddle handy, so I fired up the K3. I don't ever recall having QRN on 20M, but it was bad. Without it, you were 579 and even with it, 569 towards the end of the QSO. I just happened to be QRV on 060 listening when I heard your CQ's. Not bad for a 25mW signal from (I think you said) a Philco transistor.
73,
Dale W4OP

Later in the day I worked K4DP (599/559) in Covington, VA (929km).

Two days later my CQ was answered by VE9TTT at the northern end of the Bay of Fundy. Fortunately, the QSO turned out better than one would think given my 309 report. We kept it going for 13minutes and Paul ended up copying everything that I sent.

The next day I met W4OP for a second time on 20m; this time in a prearranged "sked." Dale reported that my signal was 579, peaking occasionally at S-8. He was kind enough to make an audio recording of my signal following our contact. You may listen to my 25mW signal as received by Dale at a distance of 1329km by clicking here.

An audio file of the original Vanguard 1 satellite beacon signal may be heard here. Information on this recording may be found here.

You can watch the March 17, 1958 blast-off of the Vanguard 1, and listen to the control room banter on the US Navy's site located here.

NASA has a wonderful write-up on the Vanguard Project. Check out this snip from the chapter on the TV-0 launch...

"Rain was falling when an hour after midnight, 8 December 1956, the countdown reached its final seconds. A variety of difficulties had plagued the final launching procedures. Snarls at the range telemetry building and at Central Control had necessitated two holds, the appearance of a ship in the waters of the impact area, another. Nerves were jumping in the crowded control room of the blockhouse, with Colonel Gibbs, the Air Force's conscientious project officer, shouting dire predictions at Bob Schlechter, the man in charge. "It's gonna blow up, Bob," Gibbs kept insisting. "Cancel! It'll never fly!"

But it did fly. Lifting off at 1:05 a.m., TV-0 achieved an altitude of 126.5 miles and a range of 97.6 miles. One of the objectives of the launch was to test Vanguard's newly developed Minitrack transmitter. With this in mind Mengel's tracking team had devised and Martin had installed in the vehicle a special Minitrack package. At T+120 seconds, two minutes after launch, the triggering device of the package-a timer-powered two bellows-contained squibs, causing them to ignite and expand, thereby withdrawing a releasing key and allowing a compressed spring to extend and eject a small sphere equipped with "roll-up" antennas and enclosing a Minitrack transmitter. Without difficulty the ground receiving units at AFMTC, the Laboratory's Mark II tracking station among them, picked up the little oscillator's plaintive beep as the ejected package descended into the sea."

Some of you will recall the launch of TV-3 didn't go so well; what Pravda christened, "Flopnik."

And here again in "living" color

Amazingly, following the tremendous explosion the little "grapefruit" satellite was found lying near the base of the launch pad. The turnstile antenna elements were cock-eyed, but it was still transmitting! You can see it on exhibit today at the National Air and
Space Museum in Washington D.C..

The little satellite successfully carried aloft by TV-4 is the oldest man-made object in space. As of today it has logged over 213,600 orbits and traveled a distance of 11.6 billion km, or 77AU.

Telefunken Match

2012-06-10T19:21:00.001-07:00

It might seem odd that I'd go out of my way to purchase a broadcast band AM receiver, given that I won't allow a factory-made ham rig into my shack. What's more, I'm not the "collecting type" and I don't listen to broadcast band AM radio.

Nevertheless, I've long admired the design of this particular "transistor radio," and when one was found going "für einen Apfel und ein Ei" I found it impossible to resist.

The Telefunken Match was an early project by the well-know German/Italian designer, Richard Sapper.

My Telefunken Match arrived in the lower half of its original box packing, along with the instruction manual. A corroded battery holder coupled with a spot on the leather case was obviously the result of the radio having been stored away with the batteries installed at some point in time (notice the spot on the instruction manual as well). Otherwise, the radio is in nearly perfect aesthetic condition.

Applying a current-limited 6Vdc supply to the radio only produced a soft hiss in the loudspeaker. A schematic diagram pasted to the inside of the radio (complete with proper node operating potentials) made it an easy task to pin-point the problem. Here's a scan of the schematic.

The 2nd IF amplifier transistor was found to be shorted from base to the emitter; a Telefunken AF172. I happened to have a spare AF138 device on-hand, which has similar specifications. The radio came to life once the replacement transistor was installed. The alignment was found to be only slightly off. The sensitivity is excellent, although the noise level is somewhat higher than what one would normally expect from this type of radio. Although I haven't yet gotten around to isolating this issue, I suspect that at least one of the transistors has become noisy and needs to be replaced.

My receiver tunes from 495 to 1870kHz (the slide-rule dial calibration is spot-on). Using only the internal ferrite antenna I had no problem copying W1AW's evening code practice session on 160m (1802.5kHz). My bench signal generator provided the beat-frequency-oscillator with no connection needed to the radio. Broadcast band AM stations filled the dial, roughly a third of which were French language stations transmitting from nearby Quebec.

Here is a scan of the original (October 1966) instruction manual.

"Mystery Tube" Superhet

2012-05-03T19:42:00.003-07:00

Here's the schematic diagram of the 20m superheterodyne receiver that I recently built using three of my sub-miniature "mystery tubes."

Component List

T1: 1.2 to 2.1uH slug-tuned with 50 Ohm coupling link
T2: 3.5 to 6uH slug-tuned; 16t primary, 4t secondary
T3: AF step-down transformer, 11H unloaded primary inductance, 22-1 turns ratio
CV1: 15 to 30pF air-variable
C1: 550pF
C2: 75pF
C3, C11: 100pF
C6, C9, C15, C16: 100pF @ 100V
C4, C13: 22nF @ 50V
C5, C14: 100nF @ 100V
C7, C10: 1000pF @ 50V
C8: 33pF
C12: 100nF
C17: 4.7uF @ 50V electrolytic
C18, C19: 39pF @ 50V
C20: 3.9nF @ 100V
C21: 47uF @ 100V
R1, R4, R8: 1Meg
R2, R6: 47k
R3, R7: 1.5k
R9: 560k
X1, X2: 11.0592MHz quartz crystal
L1, L3, L4: 10.7MHz slug-tuned IF "can" with internal capacitor removed, ~2.3uH
L2, L7: 3.5 to 6uH slug-tuned
L5: 2.2mH RFC
L6: ~10uH slug-tuned
HP: 600 Ohm headphones
V1, V2, V3: Raytheon subminiature pentodes; type QF721 (February 1953 date-code)

Circuit Description

The first converter stage generates a VFO signal in resonator CV1/C1/T2 via link-coupled feedback from V1's anode. The VFO tunes from 2.9465 to 3.0165MHz in order to cover a receive frequency range of 14.0 to 14.07MHz. The 20M input signal from the antenna is injected via resonator T1/C2. Converters such as these can be plagued by interaction between the input and VFO resonators, however the problem may be alleviated to a large extent by operating the VFO at a frequency well-removed from the input signal resonator. In the above receiver, adjustments made to the 14MHz input tank circuit, or changes in input loading, pull the receive signal beat-note only very slightly. The low VFO operating frequency also aids the receive frequency stability.

The quartz crystal bandpass filter configuration dates from the 1930's; I believe it was first known as the "Telefunken Filter." DJ2KY appears to have further popularized this filter amongst European hams with a pair of articles titled, "Ein Amateur-Kleinsuper mit Quarzfilter." These appeared in the July 1956 and May 1957 editions of Funktechnik magazine. In the above circuit, L2 forms a parallel resonant circuit at the IF frequency in conjunction with the quartz crystal's parallel capacitance (holder capacitance). However, given this small capacitance (~5pF or less) would require a rather large resonating inductance, I've added an external capacitor, C8, in parallel. Using an 11.0592MHz "microprocessor" crystal taken from my junkbox I measured the bandpass filter center frequency at 11.0535MHz. The opposite sideband signal suppression approaches 30dB...a modest performance by modern standards, but it feels like luxury having exclusively used simple regenerative and direct-conversion receivers these past four years!

I chose to use this filter primarily out of historical interest. No doubt the more common, one-crystal, half-wave bridge configuration would have worked as well; or better yet, a three or four pole ladder crystal bandpass filter.

As explained in my April 22, 2012 blog post, I had originally hoped to build a 20m superheterodyne receiver using only two sub-miniature pentodes. However, the quartz crystal filter had too much interaction with the crystal-controlled oscillator frequency in the second converter stage. I found it necessary to include an IF amplifer/buffer stage between the first and second frequency converters.

The second converter stage is somewhat unusual inasmuch as the screen grid (G2) is used as the control grid of a quartz crystal-controlled Miller oscillator that serves as my BFO. I chose the (parallel resonant) Miller configuration given its suitability for use as a VXO. Using an adjustable inductor in series with the 11.0592MHz crystal I had no trouble pulling the BFO frequency down to my 11.0535MHz bandpass filter frequency plus or minus ~800Hz.

I found that adjusting L7 to produce the maximum BFO signal amplitude at the V3 screen (G2) overdrove the second mixer and reduced its conversion efficiency. The situation was greatly improved by de-tuning L7 such that the BFO signal amplitude measured ~500mVpp on the V3 screen (using a high-impedance probe). This seems reasonable given that my early 1970's edition of the ARRL's Amateur Radio Handbook recommends that the sum of the signal and oscillator voltages impressed upon a pentode mixer grid should not exceed the grid bias voltage.

The receiver audio output signal level well suits me, although I admit that I generally prefer receivers with a considerably lower than normal audio output level. I think most folks would add at least one audio amplifier stage to this design.

Speaking of which, I did go on to build a two-tube version of this receiver. Only, I used a sub-miniature 1V6 pentode/triode in place of the 2nd converter stage shown above. The improved BFO isolation provided by the 1V6 allowed for the elimination of the IF amplifier/buffer stage. However, having become accustomed to listening to signals with the above receiver for several weeks, the minimized QF721/1V6 design sounded a bit too quiet for my liking! I ended up adding one-stage of audio amplification using a black, top-hat style, germanium transistor; type 4JD2A6, dating from 1958. The collector supply potential was provided by my 1.2Vdc filament supply voltage.

Here are two close-up photos of the QF721/1V6 receiver. The first converter and crystal filter are shown in the first photo (notice that I'm not canceling the quartz crystal parallel capacitance in this photo). The 1V6-based 2nd converter and transistor audio frequency amplifier appear in the second photo.

Both receivers appear to work equally well aside from the fact that the 1V6 is considerably more microphonic than the QF721.

Birdsong

2012-05-01T12:10:00.003-07:00

The second episode of the BBC's adaptation of Sebastian Faulks' Birdsong, was no less violent or sad than the first. But it was, if anything, more powerful.

I've been a library-rat for years; reading obscure philosophical texts: thinking, writing, wondering. As a result the world is slightly less mysterious to me now than when I was fifteen years-old. But browsing through my old journals, I was struck sometime ago to see a convergence emerging in my thinking.

The thesis of the film, Birdsong, was uttered by Jack, the miner.

"All that matters is to love and be loved."

I once thought that I might be content if I could only better understand the world. I've since discovered that understanding the machinery of this world alone, is at best, secondary. I don't just want to observe and theorize about how the building blocks of the world are setup, I want to have a vested interest in how they're stacked. I now believe that it's love that converts the curious spectator of life into a full-fledged participant.

"All, everything that I understand, I understand only because I love." Leo Tolstoy

Birdsong is available gratis for viewing on the PBS website for a limited time. It's among the best films that I've seen.

http://www.pbs.org/wgbh/masterpiece/watch/index.html

Two-Penny "Mystery" Tubes

2012-04-22T18:46:00.026-07:00

I took a chance on a little box of QF721 "mystery" sub-miniature tubes some weeks ago; paying the 1953 equivalent of two and a half cents per tube (including postage!).

As Raytheon used the "QF" prefix to indicate an experimental or special-order tube, the specifications for this device may never have been released to the public. However, the listing photo suggested these were pentodes in a T2x3 glass bulb. I also assumed that it used a directly-heated cathode (filament) that was so common in Raytheon's other lines of sub-miniature tubes.

Upon the arrival of my "mystery" tubes I noticed they were stamped with one of two date-codes: "248" (November 1952) or "308" (February 1953). They arrived in the original Raytheon cardboard "egg carton," on the side of which was printed: "Job 102," "R.T. 6822," "Part# QF721," "Type 43," "Coded 308." I also noticed what appeared to be an inspector's stamp in which a letter "H" was adjoined to the letter "R". What was this "HR"?

Playing the technological "history detective," I uncovered a single reference to the QF721. In this patent (filed November, 1952) the inventor chose a QF721 pentode for the second audio amplifier/modulator stage of a miniaturized UHF walkie-talkie. The patent drawing shows a crystal-controlled AM transmitter and superegenerative receiver, all built from Raytheon sub-miniature vacuum tubes.

Ah...but look who the patent is assigned to: Hoffman Electronics Corp., Los Angeles, California; the sister of Hoffman Radio Corp., also of Los Angeles. That would explain the "HR" inspector's stamp. What's more, the fellow that sold me these tubes lives on the outskirts of Los Angeles.

Hoffman Radio began making tube-type consumer radio equipment in 1941. Following the war they went on to produce televisions, tape recorders and even Geiger counters. You may recall they were an early adopter of photovoltaic cell technology. For example, they produced the "solar cells" used in our Vanguard Satellite program. In fact, they produced a solar powered transistor radio as early as 1957; the Hoffman P411.

I suspect that Raytheon made these tubes as a special order for Hoffman Radio. It may be that Hoffman used the QF721's in one or more of their military contracts, and the engineer working on the UHF walkie-talkie design pulled them from the stockroom in order to get on with his project.

Although I haven't located a data-sheet for my QF721's, at least I now have an example of it used by a (presumably) competent designer. For example, the patent drawing shows the QF721 filament in parallel with a Raytheon CK527AX (for which the specifications are available). Thus, I know the QF721 was designed for use with a 1.25v filament supply voltage. At this potential the QF721 filament current measures ~100mA. Comparing these numbers with other T2x3 bulb sub-miniature types in Raytheon's catalog (along with its established usage as an output AF amplifier stage) leads me to believe the maximum cathode current rating would be in the range of 3 to 4mA at a B+ potential of 45 to 60Vdc.

My first project using the QF721 was a 0V0 regenerative receiver for 40m CW using tickler feedback. A potentiometer in the screen supply provided the regeneration level adjustment. I filled a sheet of paper with DX calls in two pleasant evenings listening with this receiver: ZS1JX, 4X4FC, PY2VJ, YO3AAJ, US3IZ, CP4BT and many others.

I next built a 20m superheterodyne receiver. It begins with a frequency converter made from a single QF721 having two L-C parallel resonators in series with the grid (at 14MHz and 3MHz). Positive feedback via a coupling link on the 3MHz resonator drives it into sustained oscillation in order to provide a tunable VFO. Due to the wide frequency separation, the interaction between the 14MHz input tank circuit and the VFO frequency is insignificant.

An 11MHz L-C resonator in series with the anode couples the IF output to a one-stage crystal filter; a configuration known as the "Telefunken Filter." It was famously used in the Köln E-52 receiver (you may listen to the motorized pre-set frequency gears whir here!). The filter appears to have been popularized in amateur radio circles in the early 60's (at least in Europe) by DJ2KY; thus, it's occasionally referred to as a "KY Filter." My filter uses a single 11.0592MHz "uP" type crystal taken from my junkbox. The opposite sideband rejection is ~25 to 30dB.

I originally connected a crystal-controlled product detector/converter made from a second QF721 to the output of my crystal filter. Again, this is a self-excited mixer. However in this circuit a second 11.0592MHz crystal is configured as a Miller oscillator using the tube screen (G2) as the oscillator input grid. An inductor in series with the crystal allows the frequency to be "rubbered" down to within 800Hz of the crystal filter bandpass frequency. The input IF signal arrives at the the grid (G1).

Unfortunately, an annoying interaction between the BFO oscillator and the crystal filter made it necessary to include an IF amplifier/buffer stage between the crystal filter and the product detector. Although I'd had in mind a two-tube superhet, these three QF721's sounded so nice together that I decided to relax the minimalism constraint, at least until I had built a matching transmitter.

My transmitter begins with a Raytheon 1V6 (pentode-triode) that uses the same T2x3 glass bulb as the QF721. The triode section is configured as a Pierce, 11.2MHz crystal-controlled oscillator. The pentode section works simultaneously as a 2.8MHz VFO and mixer. This heterodyne exciter tunes from 14.0 to 14.7MHz. The exciter drives a QF721 PA, producing a maximum output of 30mW. Keying is accomplished with a PNP transistor in series with the PA anode and screen 50Vdc supply line. The exciter crystal-controlled oscillator is switched off whilst I'm receiving. It would be better to instead shift the transmit VFO frequency upwards while receiving in order to avoid several seconds of frequency shift until the 1V6 reaches its operating thermal equilibrium.

Listening to my receiver while working on the transmitter, the RMS Titanic commemorative station, GR100MGY, came to my attention. I learned this station would remain on the air until April 15th; exactly one-hundred years to the day since the great disaster. My desire to work GR100MGY became an incentive to press on with the transmitter.

I judged the setup to be air-worthy on 12 April. In the afternoon I came across GR100MGY working through a pileup. I joined in, and spent at least the next hour calling. At last, there was a lull in the activity and I must have finally turned up alone. The GR100MGY operator replied, "EA1TJ 599." He picked up my correct call on the next and it was over in an instant. Got 'em with 30mW!

Sliding back down the band I heard G3HGE just signing with a state-side station. I quickly sent my call. Silence. I called again, this time with the /QRPP suffix. He came right back with a 429 report. He sent, "UR CHANCING IT WID QRP CNDX NOT SO GUD." He also commented (correctly) on the start-up drift in my transmitter. Alas, another station started in with a CQ and he heard nothing more from me after that.

In my haste I hadn't re-peaked my transmitter before calling him. Without changing any of the settings I measured my output power at 16mW.

I found a nice note from Tom in my inbox the next morning. He wrote

"I was an RAF Wireless operator with Bomber Command and we were trained to listen for weak and watery signals so finding you was about normal for me, I spend a fair bit of time grubbing around in the noise floor of my rcvr looking for signals like yours."

On April 14th I worked: OK6DJ with 29mW (599/559), F8DGY with 28mW (599/559) and SP3GXH with 24mW (599/459). When F8DGY heard about my output power he asked for the details of my setup. He copied everything with no repeats required! In a follow-up email, F8DGY wrote

Hello Mike,

Tnx for this nice QSO with ur QRPp station, Vy interesting but it must take patience! So congrats agn cu next time. Here 800 w 3ele spiderbeam. IC7400. Ur signal was good not much difficulty to hear you!

73 Chris

The complete station is shown in the upper photo. The lower photo is a close-up of the transmitter. I hope to post the schematic diagrams in the near future.

OZ3FD's Crystal-Clear Remembrance

2012-02-13T17:14:00.000-08:00

Hi Henry,

I heard you the other evening on 80m CW with a galena and
cat's whisker ("Crystal") receiver. I used a BFO of course, but your signal did all the work. It's pretty neat to think that your signal travelled from Denmark to Vermont and still had enough energy remaining to wiggle the diaphrams in my headphones! You were a perfect copy here...every bit as loud as some domestic stations.

Ciao,
Mike, AA1TJ

Hi Michael,

Some actor once said, "Make my day" - I know at the time it was said it had another meaning. But never the less - Thank you very much for the SWL report recieved on a reciever that could had been made 90 yrs ago. You did not make my day, you made much more.

My thoughts was immediately back to the time where I sat in the shack listening to my father, OZ6PK, making QSO`s with his two tube AM transmitter. Me siting on the floor making the kind of reciever you heard me on.

Writing these lines brings tears in my eyes - not sad tears, but tears of good memories.

Today, as you could hear, I have a good set-up using the K3 with an old Heathkit PA aproxx 500 watt. The antenna is a vertical with 1 km. radials.

Best of 73,

Henry, OZ3FD

DL3PB's All-Tunnel Diode Parametric Triumph

2012-02-09T07:15:00.000-08:00

My friend, DL3PB, has done something amazing with a pair of Russian-made tunnel diodes! Peter's imagination and patience are truly an inspiration. Congratulations OM! In his own words...

"I'd like to share with you a long-cherished dream, that recently came true, fourty years after I came to read about hams using tunnel diodes to make QSOs when I was aged twelve or so:

Finally I managed a first skywave QSO with my PARASAKI-transceiver, an 'all diode' rig: Christophe/F8DZY replied to my very first call on 20m band in REF-contest last weekend. I was running 2mW into a temporary vertical dipole on my balcony.
Distance between us is 918km - obviously OM Christophe has excellent ears.

Those interested in the cruel details of my circuit, please find attached a schematic and a photo of the pretty ugly setup. The circuit is designed straight-forward with exception of the parametric VXO, derived from Mike/AA1TJ's famous Paraceiver design. (see http://fhs-consulting.com/aa1tj/paraceiver.html )

The low impedance of the high peak-current tunnel diodes make it very difficult to build a crystal controlled oscillator rather than an LC oscillator, synchronized by the crystal more or less, at least on the higher SW bands. The Parametric VXO provides a crystal-stable, chirp-free signal on expense of an output power of two milliwatts only instead of ten, but with an amazing spectral purity, no need for a low pass filter or such.

Of course it sounds pretty cool making a QSO with a 'bunch of diodes' and a parametrically excited crystal, but believe me or not, I'd preferred to bring that full ten milliwatt into the air - on the other hand that approach allowed to tune the rig a bit ( ~ 5kHz/per xtal ), which turned out to be much more valuable than a few milliwatts more while being 'rock-bound'.

The receiver in its 'gain-less' version works fine for strong signals - while listening to QRP(p) stations, the moderate gain of the audio amplifier helps a lot. A comfortable frequency shift between receive and transmit is realized by the 5µH inductor at the LO-port of the mixer, with little effect on sensitivity."

QRP...easy as 2N123

2012-02-08T09:07:00.000-08:00

I recently put together an 80m CW transmitter using a pair of 2N123 germanium transistors, both of them bearing July, 1959 date-codes. The first stage is a Colpitts-type VXO. A 3.58MHz ceramic resonator tunes from 3501 to 3560kHz using a series-connected variable capacitor. A second 2N123 transistor is configured as a Class-C, common-base power amplifier. The RF output is ~50mW, although it falls to 45mW at the low end of the band.

The basic transmitter schematic is shown below; the transmit-receive keying relay does not appear in this drawing.

Part values

C1: 27pF silver mica (s.m.)
C2: 330pF s.m.
C3, C4: 150pF s.m.
C5, C7: 48nF
C6, C8: 430pF s.m.
CV1: 15 to 230pF air-variable
R1: 100k
R2: 1.5k
T1, T2: 3.5 to 6uH slug-tuned; 16-turn primary, 3-turn secondary
X1: 3.58MHz ceramic resonator
Q1, Q2: 2N123 germanium PNP transistors

Adjusting T2 for a peak RF output, the highest harmonic energy is -35dBc (the 2nd harmonic). However, by tuning slightly off-peak, the peak harmonics drop below -45dBc. Thus, no further filtering is required.

I've paired this transmitter with my Cat's Meow galena and cat's whisker receiver. While receiving, the RF output signal from the continuously running transmitter is relay-switched into a 50 Ohm cermet potentiometer working as a dummy load. A sample of this signal is taken from pot's wiper to provide the receiver beat-frequency oscillator (BFO). A single, miniature DPDT relay is keyed in order to provide the required switching. A reed-relay was initially used to switch a 10pF capacitor across C4, for the purpose of providing a receive-increment-tuning (RIT) frequency-shift. However, I discovered that with careful tuning the variation in transmitter loading is alone sufficient to provide a RIT frequency shift of 750 to 1200Hz (from the bottom to the top of the band).

At G3XBM's prompting I measured the minimum detected signal (MDS) level required at the receiver. Using a factory-made germanium diode in place of the galena and cat's whisker, I could just copy a -118dBW signal. This is an absolute power of 1.5pW, or 8.75uVrms across a 50 Ohm resistance. Holding the input step-attentuator at this setting, I re-installed the galena and adjusted the cat's whisker until I could just hear the signal in my headphones. For the same signal copy that I had with the germanium diode it was necessary to switch a 3dB pad out of the circuit. Thus, the best sensitivity that I could wring out of the galena was -115dBW. This is an absolute power of 3pW or 12.4uVrms across a 50 Ohm load.

It's interesting to review a similar measurement that I made for my 80m Reggie transceiver (the receiver was also gain-less and I used the same pair of headphones) back in 2009. I then measured an MDS of -120dBW; which is an absolute power of 1pW, or 7uVrms across 50 Ohms. Allowing for the subjectivity involved in making these measurements, the results of both tests when using commercial diodes are very close indeed.

Here's a photo of the "finished" 80m station. The transmitter appears on the rear proto-board, while the "crystal receiver" is up-front. Again, the small green and black reed relay appearing on the left-hand side of the transmitter has since been removed ("Simplify, simplify..." Thoreau :-).

In two evenings I've made eleven QSOs with this setup.

KA1ANW 579/599 (him/me) Sharon, MA          225km
WA1AR     579/599             Wrentham, MA          255km
N2UU        579/449               Voorhees, NJ          504km
W1FL        559/339                    Stowe, VT            46km
W3NW      569/539           Lock Haven, PA          504km
KT8R         559/229                        Alto, MI        1021km
W3ZT       579/559            Skaneateles, NY          319km

W1PID 579/589 Sanbornton, NH 112km

WA3MIX   579/579           Williamsport, PA          469km
K1ESE       589/559             Waterford, ME          163km
N8ER    569/559      Parsons, WV    797km

My QSO with W1PID lasted nearly an hour. Jim began with an ICOM 7000 at 2watts, but he quickly switched to his Elecraft K2 in order to play the "QRP Limbo" game. Jim reduced his power in steps: 500mW, 200mW and finally 100mW. His 100mW signal came through my cat's whisker at a perfectly readable 529! I received a long transmission very nicely at 200mW, aside from a bit of QRM towards the end.

I particularly enjoyed my contact with W3ZT on account of his unusual transmitter. Joel was running a 1950's-vintage URT11, which was built for the CIA and commonly used to provide CW communications for our foreign embassies. We had a solid contact lasting 15 minutes.

I admit that I get a kick out of the responses when I explain my setup. For example:

N2UU sent, "TELL ME YOU ARE JOKING."

WA3MIX said, "MAN TTS ABT AS OLD SCHOOL AS U CAN GET = SOUNDS GREAT WID GUD KEYING ES VY STABLE."

K1ESE replied, "DONT THINK I EVER WRKED A GUY ON AN XTAL SET FER RX HI = PRETTY AMAZING"

I've heard a number of DX stations as well in the last two nights. ON6AB, OZ3FD and DL2WR had particularly strong signals here.

A Swedish Sputnik and More

2011-12-28T14:46:00.000-08:00

Johnny, SM7UCZ has made a top-notch job of his new Sputnik transmitter!

The schematic diagram of his circuit layout, plus more photos may be found here.

Among the many interesting tube and transistor QRP projects to be seen on Johnny's web site is the story of a hand-transcribed copy of Frank C. Jone's, 1938 edition of, The Radio Handbook (please click here).

OM, Sven Bernholm, SM3RN (1888 - 1963), laboriously translated this work into Swedish whilst standing radio watch in the years 1944 to 1945. Sven beautifully hand-copied over 400 pages of text, schematics, drawings, graphs and tables. I'm surprised that he didn't illuminate the pages in the fashion of medieval monks! His little side-notes are especially interesting; for example

5/5/1945: "Denmark and the Netherlands, free!"

7/5/1945: "Germany surrendered; Norway free!"

12/4/1945 "Roosvelt dead - Allies 6 miles from Berlin!"

Johnny recreated a Frank Jones-type "push-pull" transmitter similar to the one appearing in Sven's transcription (here).

There are several Parasets, a Hartley transmitter, a tube superregenerative receiver for the VHF BCB and a transmitter built to operate on 1.5Vdc (and less). The fine art of homebrew QRP is alive and well in this little corner of Sweden!

The Cat's Meow

2011-12-21T12:40:00.000-08:00

"Who would not, after once trying it, admit that the three element vacuum detector is the most sensitive device known for the reception of Herztian waves? The author freely grants this, but claims that for pure, unalloyed pleasure one must experiment with the less sensitive detecting devices before one can know the keen delight of the radio game." Lloyd Manuel, QST Magazine; July 1916, "What's the Matter with Galena?"

I got the "galena" itch again yesterday. Luckily, it's an easy itch to scratch as no more than five minutes are needed to lay down a heterodyne receiver on the protoboard. My circuit is shown on the left in the drawing below. For comparison, the heterodyne receiver used for long-distance radio testing aboard the USS Salem in 1913 appears on the right-hand side (please click-on the photos in order to enlarge them).

Component values for "The Cat's Meow" on 80m

C1: 510pF
C2: 2.8nF
T1: 3.5 to 6uH, slug-tuned, 16-turn primary, 6-turn secondary
HP: 600 Ohm magnetic headphones
BFO: I used my bench RF signal generator set for ~ 1Vpp

Not shown in my schematic diagram is a 10nF capacitor connected between the mixer diode and the BFO. I simply forgot to include it in my drawing.

The mixer diode is a galena and cat's whisker; a gift from my pal, DL3PB. The receiver appears to the right of the R/T toggle switch in the photo below.

In order to get on the air as quickly as possible yesterday I rebuilt my old Vermont Snowflake transmitter. The VXO'd 3.58MHz ceramic resonator allows me to cover most of the 80m CW band. I used slightly different component values for the transmitter low-pass filter yesterday, but it was the same circuit otherwise. The RF output power is 17mW into my 80m half-wave wire, end-fed wire antenna.

It would have been possible to use the transmitter output for my receiver BFO, but that would have meant including a provision for receive increment tuning (RIT). I decided to keep everything as simple as possible yesterday. The manually operated SPDT switch shown in the photo below transfers the antenna between the transmitter and the receiver. A DPDT switch would have been better as I could have used the second pole to switch-off the transmitter oscillator while I am receiving. The complete setup appears in the following two photographs.

I made my first QSO literally minutes after becoming QRV. I answered WA1HFF's CQ and he came right back to me. I made a total of three QSOs for the evening.

WA1HFF 579/449 Longmeadow, MA 141mi/227km 50w/dipole

K3SEW 579/439 Howard, PA 326mi/524km

N1MX 579/439 Walpole, MA 154mi/247km 100w/dipole

When I came up to the house I found an email message from John, KQ1P

Mike-
I just listened to your CQ QRPP. I copied you 439 here in ME. I called you at 1 watt to my 80M loop = NIL. Went for 7dB increase at 5 watts = NIL. Your signal sounded good, some QSB. Time to retire now, will listen for you tomorrow if you try again. What new experimental rig are you using?

Gosh, I should have heard him, even with 1 watt! We're set to try again tonight.

Here is the list of Reverse Beacon Network captures of my signal last night.

22 December 2011:

KQ1P 219/449 Orland, ME 207mi/331km 5w

Today's RBN log of my 17mW signal

My affection for the galena and cat's whisker radio began when I was a Cub Scout in the mid 1960's. I remember being intimidated by the sight of this circuit in my Wolf Scout handbook. One of these days I really ought to build this radio. A few minor changes and the addition of a BFO for CW reception would make it into a 1st-Class DX machine!

W1PID's Christmas Tree DX Adventure

2011-12-15T14:19:00.000-08:00

December 23, 2002

It was the day before the night before Christmas and all through the
house not much was stirring. The girls had gone out for some last
minute shopping.

I had this goofy idea...why not load up the lights on the Christmas
tree in the living room for an antenna? Nice holiday QRP experiment...

So I gave it a try. I worked Norway on 20 meters and Scotland on 15
meters with 5 watts and a little tuner.

When I told Fred, GM3JKS about the setup, he sent back:
"Congratulations on the 5 watts and Christmas tree lights for antenna. This is a first. Hope your family is impressed." I told him they were out shopping and they probably wouldn't be a bit impressed!

The whole thing was magic, but not on the scale of Santa, his sleigh
and the coming down chimneys. It was, after all, thirty feet or so of
wire wound spirally around the tree. 100 lights in all. And they didn't
glow or anything. I'd hooked the tuner up to the ground side of the
plug, and I'd strung out a 20 feet or so of counterpoise along the
floor. I'd worked England from the dining room table before with a 3
foot antenna, so I knew it was all possible.

But it was fun. More than that...it was a little Christmas ham magic,
and I think I'll try it again next year.

Happy New Year from Jim W1PID.

Thanks for allowing me to post this, Jim!

A Saturable Core Polyakov Mixer on 80m

2011-12-15T09:32:00.000-08:00

Vladimir Polyakov (Вертикал Полякова), RA3AAE (on left)

This 80m "Polyakov" direct-conversion "proof-of-concept" receiver uses a pair of vintage ferrite computer memory toroid cores in the subharmonic mixer. A 1.75MHz beat frequency oscillator (BF0) drives the ferrite cores along the full "B/H curve." The cores are driven alternately in and out of saturation twice per working cycle.

While the cores are saturated the inductive reactance falls to a low value and the signal from the antenna passes through the mixer with little attenuation. While the magnetic flux is passing from one saturation state to the opposite state the inductance rises (ideally) to a relatively high value. This high reactance momentarily blocks the antenna signal's path through the mixer. The idea is to create a commutating mixer from a time-varying, series reactance.

I'd hoped that it would be possible to hear 80m CW signals with only a pair of headphones connected to the mixer output. Unfortunately, the conversion loss is presently some 35 to 40dB higher than is typically seen with a diode mixer.

The mixer ON/OFF ratio ought to be roughly unity over the course of an incoming signal cycle, whereas my saturable reactor mixer spends spends far too long in the ON (saturated reactance) state. Another issue is the maximum reactance obtained in my present setup is too low in relation to the 50 Ohm path impedance.

In order to measure the "ON" feed-through signal loss an experiment was performed with the BFO signal replaced by a DC source. The current was raised until the inductors saturated. In this experiment I used a variable capacitance in series with the mixer signal windings in order to better cancel the residual inductance. I measured 1.46dB of signal attenuation. No improvement was seen with an RF choke placed in the BFO windings. This tells me the twin core signal cancellation technique (due to reversed polarity windings) is working well.

It wasn't quite so easy to measure the unsaturated feed-through signal attenuation under time-invariant conditions. When the DC bias test current is switched off the saturated ferrite cores simply revert to their remnant state. This is exactly what you'd expect of a semi-hard ferrite computer memory core. It's only possible to get an idea of the maximum reactance by reversing the DC bias polarity and slowly increasing the current; watching the 3.5MHz signal for the point of maximum attenuation. I measured a maximum total attenuation of 9.34dB. This "best-case" differential attenuation is only 7.88dB; which helps to explain why the conversion ratio is so poor.

This mixer working alone into the headphones (no semiconductors in the signal path) produces an audio beat-note with a few hundred millivolts of 3.5MHz signal injected at the antenna input terminal. Again, this is not exactly stellar sensitivity.

So much for the bad news. The good news is that I was able to copy a fair number of stronger 80m on-air CW signals using this mixer plus one stage of audio amplification. I used a 2N35 NPN germanium-alloy transistor that was made by Sylvania in 1956. Early evening code practice sessions from W1AW are easily copied anywhere in my (admittedly, tiny) shack with the headphones resting on the workbench.

I was careful to insure the input to the transistor amplifier is free of RF energy so there's no doubt the saturable reactors are providing the RF mixing action. Please notice the lack of a band limiting filter between the antenna and the mixer input. I expected this mixer would behave well in the presence of strong adjacent and out of band signals, and so it does.

My remote antenna coupler provides a return path to ground for audio frequencies. Lacking this, it would be necessary to connect a radio-frequency choke across the receiver antenna input terminals; something in the range of 1 to 2.5mH should work well.

C1, C2: 1uF

C3: 100uF

C4: 330pF

R1: 330k Ohms

L1: ~3mH

T1: 50 Ohms to 1500 Ohm AF step-up transformer

T2: 10k Ohms to 600 Ohms AF step-down transformer

HP: 600 Ohm magnetic headphones

Q1: 2N35 (a mid-1950's vintage germanium alloy transistor)

SR1, SR2: 50 turns on signal winding, 10 turns on BFO winding.

The semi-hard, ferrite cores used in my saturable reactors, SR1 and SR2, each measure 1.27mm diameter by 0.395mm in thickness. They were made in the 1950's-70's for computer magnetic memory use by Kombinat VEB Keramische Werke of Hermsdorf, in the old DDR.

By the way, my saturable reactor mixer has much in common with a sensitive flux-gate magnetometer. Sure enough...a small magnet waved within 30cm of the mixer produces a curious "scratching" sound in the headphones. The same magnet set in place within 3cm of the mixer blocks all mixer action. I expect the external magnetic field simply prevents the BFO from effectively driving the core flux around the "B/H loop."

Here's a photo of the experimental receiver. The ferrite-based mixer appears on the left. The 1.75MHz BFO is in the background.

Here's the original container filled with tiny magnetic computer memory cores.

An Early Winter Thanksgiving

2011-11-24T14:47:00.000-08:00

Victoria and I had a tranquil and happy Thanksgiving. We began the day with a long walk through a winter landscape; courtesy of yesterday's 25cm snowfall. As usual, much of our organically grown Thanksgiving dinner came from our garden. The items that we grew ourselves are italicized below.

Acorn squash stuffed with brown/wild rice, French lentils, mushrooms, onions, cranberries, bread crumbs and sage
Green beans with tahini sauce
Cranberry-apple relish
Roasted red and yellow beets, carrots and almond slivers
Pumpkin pie for desert (not shown)

For some, Thanksgiving wouldn't be the same without the turkey. As such, I'm including a photo of a wild turkey in flight. Victoria discovered a gathering of more than a dozen turkey just outside our front door some weeks ago. Of course when she stepped out with the camera they were airborne before she could depress the shutter.

A photo of this year's kitchen garden.

We harvested ten pounds of shelled hazelnuts from our mini-orchard of nineteen trees in September. The hazelnuts shown in the left-hand basket are still in the cob. The ones on the right have been shucked but not yet shelled.

We picked 140 pounds of apples this year. Filling for one apple pie per month for the next year is in the freezer and we've a half-dozen large bags of dried apple rings in the pantry.

We made a total of three gallons of apple sauce. The rest of the apples are down in our root cellar, along with the potatoes, carrots and other miscellaneous root vegetables.

“If you look the right way, you can see that the whole world is a garden.”
Frances Hodgson Burnett

Lavender 2011

The Tao of QRPp

2011-11-19T21:48:00.000-08:00

I sometimes imagine that milliwatting on the high-frequency bands must be a bit like sailing a dinghy across a busy ocean shipping lane. For long spells it's as though you are alone, bobbing upon a vast sea. Suddenly a huge ship appears from nowhere. Judging from it's course and speed there's little doubt that it hasn't seen you, and it likely never will. Your only option is to get out of the way. Only when it has passed can you return to your intended heading. It's not only the traffic, but weather as well that can upset your hopes for a successful voyage.

If a man is crossing a river
And an empty boat collides with his own skiff,
Even though he be a bad-tempered man
He will not become very angry.
But if he sees a man in the boat,
He will shout at him to steer clear.
If the shout is not heard, he will shout again,
And yet again, and begin cursing.
And all because there is somebody in the boat.
Yet if the boat were empty.
He would not be shouting, and not be angry.

The challenge of milliwatting involves navigating through both QRN and QRM. The operator knows before he sets out what he's getting himself into. One moment you're sailing on an empty frequency and the next you find yourself 40dB beneath the hull of a leviathan.

Nature made QRN and QRM alike. And whether QRN or QRM, every difficulty that we face adds another line of bumpers to the pin-ball table. One of life's little joys is reflecting on where all the bumpers were when you did something worth remembering.

Two winters back, while calling a DX station on 80m, another station turned up on frequency with the comment, "PISS WEAK" at the end of several of my transmissions. In a "just so" story the DX station would have picked up my call, allowing me to clench my jaw and send for all to hear, "RIG ONE TRANSISTOR ES 85MW." Of course the DX station didn't hear me that night. In retrospect I'm glad that he didn't. At least not then.

Who can free himself from achievement
And from fame, descend and be lost
Amid the masses of men?
He will flow like Tao, unseen,
His steps leave no trace. He has no power.
He achieves nothing, has no reputation.
Since he judges no one
No one judges him.
Such is the perfect man:
His boat is empty.

Chuang Tzu

My First QRPp Contact

2011-11-18T21:25:00.000-08:00

My "Elmer" KØYTI (now AAØA) handed me a stack of 73 Magazine back-issues back in 1971. I was fourteen years-old at the time and already becoming bored with my store-bought radio equipment. I responded to an advertisement in one of the 73 Magazine issues (shown below) by sending off an order for $3 worth of MPF102 JFETs. I chose the MPF102 because it was the least expensive device offered!

Having received my field-effect transistors I set about trying to build a crystal-controlled oscillator for the 40m band. I mounted the components on several bakelite tie-strips, which were themselves screwed down onto a wooden base.

After several days of trial and error I finally heard the oscillator's signal on my shortwave receiver. I used my only piece of test equipment - a VOM that I had purchased from a nearby Radio Shack outlet store - to measure the total DC input power to the oscillator. With a fresh pair of 9Vdc "transistor radio" batteries in series, I calcuated the input DC power was just over 50mW.

Soon afterwards I had the idea of coupling this oscillator to my 40m dipole antenna. Having no idea how to calculate the optimum number of coupling turns at the tank inductor, I tested various windings by measuring the relative output at the antenna with my VOM, set to read "volts," in series with a germanium diode.

Having placed my straight-key in the circuit I began calling CQ. I didn't know if I could be heard outside my neighborhood, much less outside of my city.

I was still at it some days later with not so much as a nibble. I must have sent out five-hundred calls to no avail when, at last, I heard a station returning my call sign. It was W3EGL/Ø in Rochester, Minnesota; a distance of 388miles or 624km. We easily exchanged reports. Obviously, I was ecstatic over the contact.

Alas, both his QSL card and my old log book are long gone, so I can not tell you what the signal reports were. However, I recall from his QSL that he'd been using a pair of military surplus "Command" radios..."BC" something or other. I remember thinking it was pretty neat that he'd heard my tiny signal on such old and basic equipment.

I called for some time, off and on, in the following weeks, but this was to be my only QSO made with a handful of milliwatts in those days. What with school, dating and jobs, I eventually left amateur radio for what turned out to be a period of over twenty-five years.

I returned to the hobby in 2008 with the aim of making "homebrew milliwatting" my primary focus. In early 2010 I rebuilt the MPF102 one-stage transmitter from memory. Using the same drain supply voltage as before, I noticed the output power varied considerably from one MPF102 to another (the Idss and Vp values lie in a broad band of values from one device to the next), but it generally fell within the range of 10 to 20mW.

However, by 2010 I had developed an interest in early semiconductors. Accordingly, I replaced the MPF102 with one of the earliest modern silicon JFET's.

The first commerical field effect transistor appeared in France in 1958. This was the Technitron; brainchild of Stanislaus Teszner. Unfortunately, this germanium alloy device suffered from very low gain and high reverse-leakage.

Crystalonics of Cambridge, Massachusetts produced the first commercially available silicon JFET in 1960. Although the reverse-leakage was vastly lower than in the Technitron, and the transconductance was an order of magnitude higher, it was a poor perfomer in comparison with modern silicon JFETs. In fact I have four of these devices in my collection. Only one of the four - type C632 - is barely capable of producing sustained oscillation at 4MHz. The listed transconductance for the three type C631 devices in my possession is only 125uMhos with a pinch-off of 30V and up to 50pF of interelectrode capacitance!

It was the advent of Jean Hoerni's planar technology in 1959 that paved the way for modern, high-performance silicon JFET's. The first of these to be produced was a line of P-channel devices made by Texas Instruments, beginning in 1962: the 2N2386, 2N2497, 2N2498, 2N2499 and 2N2500.

I replaced the MPF102 in the QRPp transmitter of my youth with a 2N2499. My sample bears a date-code of September 1962; a very early device indeed. Given the May 1966 Texas Instruments price guide lists the 2N2499 for $12.90 (equivalent to $86 in 2010), I shudder to think what it must have cost in 1962 (the first JFET project to appear in QST Magazine debuted in 1966).

The RF power output was actually a bit higher using the 2N2499; at 28mW vs. 10 to 20mW with the MPF102s. I paired this transmitter with a regenerative receiver built from an early 2N2386 JFET (regenerative detector), direct-coupled at the source resistor to a 1957-vintage 2N107 PNP germanium transistor (AF amplifier stage).

On 6 May 2010, K1GOW in Providence, RI answered my CQ on 40m. Joe was running 3 watts to an end-fed wire only 15 feet off the ground. The distance between us was 167miles or 270km. The reports were 569/439.

On the next day I worked KA2PQY in Milmay, NJ (338mi/544km) with 569/339 reports.

On 10 May I worked two stations: N2AYI in Carney's Point, NJ (332mi/535km) with 579/539 reports, and, KA2KGP in Forestville, NY (340mi/547km) with 569/339 reports. BTW, Tom's QRZ page notes that he is a deaf CW operator.

Something Crazy's Going On

2011-11-10T15:52:00.000-08:00

I've been out of the saddle for some weeks now due to family issues. At last, this afternoon I lowered myself down into the Hobbit Hole with the aim to have some much-needed fun. Well, I did that plus some; only, I'm a little confused right now.

Once in my shack I quickly threw together a 40m, crystal-controlled, Pierce oscillator using a germanium grown-junction alloy transistor. This one was made by General Electric back in September of 1956; type 2N78. As the maximum data-book 3db-down cutoff frequency is only 6MHz, I'm pushing it a bit. With 12V on the collector the RF output power is 5.6mW. Not much, on the other hand the worst harmonic is -45dBc with just a simple LC tank in the collector...no extra LPF required.

1957 Radio Shack Catalog

Next I built a one-transistor regenerative receiver using the same type 2N78 transistor. It even has the same date-code. For simplicity I placed my 1950's Czech military surplus "4k Ohm" headphones directly in the collector return to the +6V supply line.

Likewise, I plumbed my Czech mil-surplus straight key to the transmitter. The antenna was my usual 135' end-fed wire erected at 35' on the ends.

The band was busy so I ended up calling CQ at 7041.6MHz; smack between some "letter" stations. I called for about an hour with no luck. Having only three 40m quartz crystals, I kept checking the lower two frequencies for a clear spot. Eventually there was a lull on 7014.7kHz so I began calling there. It didn't last long. In less than five minutes I found myself buried in a resurgence of DX activity. But now I noticed my third quartz crystal frequency was open so I QSY'd up to 7029.7kHz, where I took up calling CQ again.

At 2134z a strong station answered my call. It was K8CIT calling from Michigan (554m/891km). Art was 589 to 599 here with his 100w and 80m loop at 60'. He gave me a 429. We ended up having a great QSO lasting until 2150z. Art copied everything I sent: details about my rig, the transistor type, my receiver, etc..

When I came up to the house for dinner I decided to check the RBN to see if any of my calls had been captured. Indeed, I was logged a number of times by RBN receivers in NH and PA, with SNRs from 1 to 5dB. But right at the top of the list was a RBN capture at a SNR of 14dB. The RBN station that logged me was DL8LAS near Kiel (3599m/5792km)! Everything about the logging seems correct: frequency, sending speed, etc.. It appears that my antique transistor was heard in Germany this evening on 40m...all 5.6 milliwatts.

15 December 2011 Update: Peter, DL3PB, may have solved the mystery! There appears to be a bug in the RBN software that occasionally prompts it to capture your call sign as sent by another station, and present it as though it had heard you calling CQ. This would make sense as the DL8LAS listing of my call is approximately the time that K8CIT would have been signing-off with me. It very well may have gotten my call sign from K8CIT. Thanks Peter!

http://reversebeacon.blogspot.com/2011/12/reducing-number-of-false-positive-cq.html

K2LP answered my CQ on 15 November 2011. The reports were 599/559. Bud's strong signal blocked my little regenerative receiver so badly that I resorted to copying the "thumps"...no tone heard whatsoever! ;o)

Disagreement

2011-10-31T12:38:00.000-07:00

Despite my having enjoyed several of A.C. Grayling's thought-provoking books, his recent, The Good Book; A Humanist's Bible, isn't really my cup of tea. That said, I enjoyed reading parts of this interview (no, not the bits about his hair ;o)

"And besides, really," he adds with a withering little laugh, "how can you be a militant atheist? How can you be militant non-stamp collector? This is really what it comes down to. You just don't collect stamps. So how can you be a fundamentalist non-stamp collector? It's like sleeping furiously."

Exactly...and it helps to explain why I wouldn't be tempted to join an association of atheists. Denying a specific belief held by another man may illustrate the sorts of things that I'm likely to disbelieve, but it says next to nothing about what I actually believe. Despite my general aversion to belief in sky gods, I wouldn't be surprised to learn that I have more in common, overall, with a given Christian or Muslim, than I would a certain, self-proclaimed atheist.

That is...as if having people agree with my own philosophical stance really mattered. It doesn't. Of those whom I would give a kidney in a heart-beat, exactly none share my philosophical beliefs. The people that I most love in the world have distinctly different religious, philosophical and political beliefs than mine. Simply put, we don't love people because they agree with us. Furthermore, we sometimes betray those whom we claim to love by merely agreeing with them when we ought to do otherwise.

"They have stopped deceiving you, not loving you. And it seems to you that they have stopped loving you." Antonio Porchia

While engaged in friendly arguments in recent weeks, I twice noticed my disputants laboring to shift the terms of our disagreement in order to illustrate that our diametrically opposed stances were in fact the same. I suspect they were worried that our friendship might be in jeopardy if it turned out that we actually did disagree on the issue at-hand.

I came away a bit depressed in both cases. Not because we argued, or because I lost an argument, but because I realized these people know so little about me, or think so poorly of me, as to fret that I might turn my back on them should their view point happen to prevail.

Epicurus taught that nothing is finer than sitting under a tree discussing philosophy with friends. With or without the tree, this mental tableaux is my idea of "the good life" as well. Bear in mind, philosophers rarely discuss their points of agreement. One might as well talk about the weather. A professor may discuss philosophy, but when two or more philosophers gather, they argue. Ideally, they argue as gentlemen or gentlewomen. Sophists argue for the sake of winning arguments. Philosophers argue as smartly as they know how, in order to jointly tug on a corner of the woolen rug that lies beneath the ordinary world; the world we already knew by the age of nine.

The person I argue most fiercely with is myself. I would think less of myself if it were otherwise. And yet someone who only argues honestly with him or herself lives in danger of intellectual inbreeding. Those who will only discuss their beliefs with like-minded people - perhaps, for fear of having an argument - commit intellectual incest.

To live in a world in which everyone were exactly alike would be to live alone in a world; all we could do is talk to ourself. Martin Buber taught that the difference between a monologue and a conversation is the "otherness," or the moment of surprise. In order to have a conversation we must be prepared to hear surprising things; otherwise, we're only talking to ourself.

It's a poor philosopher that can't spot three ways that his every assertion is incorrect. The trouble is that we argue our ideas as though our lives depended on them, when it's less about the static ideas themselves than it is the passion with which we pursue them.

"Man is ready to die for an idea, provided he doesn't quite understand it." Paul Eldridge

I wasn't born holding my present beliefs; I arrived at them through an arduous process. These beliefs comfort me. They help me to make my home in an otherwise inhospitable Universe. Comfortable as they are to have around, rather than wrap myself into a little ball around my present beliefs, my goal is to rid myself of them. That's right, my ongoing quest is to replace my present beliefs with better ones. I shall never be content on this accord. Philosophy is not something you have, it's something you do. To paraphrase Sir David Butler, a better philosopher is not one who is right, but one who is wrong for more insightful reasons.

Political argumentation is unnecessary (even unhealthy) in totalitarian states. Democracy, on the other hand, amounts to an ongoing argument about how best to govern ourselves.

And so I argue that argument is necessary for our well-being. An argument doesn't necessarily signal a break-down of etiquette or diplomacy. A signal of agreement is not a reflexive sign of friendship. Rather, you do me a favor by patiently explaining why I am mistaken. In a dialogue it is necessary to both speak and listen. And when we listen we ought to be prepared to hear new and strange ideas. A wise philosopher by the name of Frank Zappa once said

"Without deviation from the norm, progress is impossible."

Immortality and the Multiverse

2011-10-30T12:31:00.000-07:00

Have you seen Roger, G3XBM's new blog, Miscellaneous Musings?

I especially liked his recent post on the simple pleasures. I'd say he's spot-on.

I wanted to comment on his topic, "Death in a Multiverse," only, it overcame the space provided. I'll just post it here on my blog.

I enjoyed reading your comments, Roger.

Suppose it were factually true that a nearly identical replica of you will continue to live somewhere in the Multiverse following your death here. Would having a nearly identical replica of you carry on somewhere "out there" effectively extend your conscious life?

Fortunately, there is no need to wait for our death in order to test this idea. The test consists of one straight-forward question, namely; Have you lost consciousness at any time since you were born? This test can be administered at any time and the results stand for all time.

The very notion of immortality stands critically on the precept that our consciousness is independent of a functioning brain or body. Thus, the test for absent consciousness is valid regardless of the present state of our brain or body. Plainly speaking; we need not wait until we die in order to test for the continuation of our consciousness. Again, this is so because immortal consciousness is not contingent upon a functioning brain, or the lack thereof.

I've taken the test and the results are unambiguous. In fact, I have lost consciousness several times in the course of my life. In each case my experience abruptly halted, only to restart at a later time. While my consciousness was "off-line" I had no dreams, nor could I reflect upon the fact that I was unconscious. Upon waking I noticed the world had apparently gone about its business while I was entirely absent from it. No "hot standby" rushed in to pick up my loss of consciousness. No secondary "light" was illuminated. Until my brain had "re-booted" there was for me only time-less nonexistence.

Indeed, those missing moments stand out no differently than the semi-eternity during which my consciousness was absent from the world prior to my birth. Of course, the fact that our consciousness suddenly arose with our physical birth should have been the first tip-off that our consciousness might not survive without our brain/body.

There is little that we can say about the world with metaphysically warranted certainty. However, it seems a fair bet that none of us will survive the death of our brain. Some of us won't survive until the death of our body (e.g. terminal coma, advanced Alzheimer's, etc.).

This isn't the last word on the subject. Granted, the person who presently peers at the world through my own eyes will eventually disappear. But new consciousness will continue to reappear (i.e., children will continue to be born). Of course they won't bear my personal identity, but they will be somebody.

Well, I wasn't born "me" either. I was born a "somebody" that eventually became a "someone;" the same as they will. They won't have my memories or share my person proclivities, but I wonder how much do those particulars actually matter? I admit it's a head-banging question, but if a child is born a nebulous "somebody," just as I once was, what is it that distinguishes one raw consciousness from another?

I believe the question has much to do with the notion of identity. I can imagine looking out through these same eyes even if my life had been radically different. If primal consciousness is fungible, then what stands between the individual consciousness within which each one of us awakened? If consciousness does not arise stamped with a "serial number," what could there be to distinguish one newly minted consciousness from another?

I don't see this as some backdoor path to personal immortality. Neither do I envision it as some type of reincarnation. Rather, I think that we ought to re-examine our concept of Self. And I think that we could do worse than to merge, or at least blur, our notion of individual self with that of our brethren; past, present and future. I suspect that I exist in this broader sense, and in some degree, in every conscious being.

If you have an interest in the subject of personal identity then you might be interested in Derek Parfit's masterpiece, Reasons and Persons. A sample of his arguments may be found here.

Sputniks 'Round the World

2011-10-11T20:13:00.000-07:00

I briefly heard G3VTT calling last Friday with his Sputnik "clone" at 14:31 UTC. Here's a nice picture of his transmitter; built from mostly vintage components.

Colin's caption for the next photo: "Snappy change-over...only one switch and a croc-clip!" Notice also his high-voltage supply (80 or 120Vdc).

Here is a photo of Dan, WA6PZB's Sputnik and J-36 bug. Very nice indeed!

Nick/WA5BDU's very 50's Sputnik transmitter. More info on his blog.

Yuri/UA3UAD's Sputnik appears in the photo below.

This Sputnik belongs to Alex/RN3AUS.

Here's a close-up of Alex's Sputnik transmitter.

Oleg, RV3GM very kindly sent me a list of contacts made to-date by the ops at QRP-RU.

Oct 4,
- RK1NA QSO with G3VTT/Sputnik 449/449
- UA1OKO works "Sputnikers" PA0PJ, DL3JIN, ON6WJ and ON5AG/QRP
- UA1CEG worked ON6WJ/Sputnik 589/599
- UA1CEG - DL4GM/QRP and IT9NMJ
- UA3UAD/Sputnik @ 1W, QSO's with G5RV, G3IOR, ON4ADR, ON5AG, S51NP
- UA0SBQ @ 1w worked HB9AFI and YT3AA

Oct 5,
- RN4AO/Sputnik @ 1 W, QSOs with G3IOR, DL3JIN, DL3NRV, ON4ADR, ON5AG

Oct 7
- RN3AUS/Sputnik @ 300mW QSO with DL4HG/qrp

I received a nice message from Victor/UA1CEX

"Working on 21060, power 1watt, I used Elecraft K-1 and G5RV antenna. I did the follow QSOs: ON6WJ, DP7TU, W1PID, G4PPK, PA0ATY, DL1NFF, ON4MB, S53AF, DL4VM, M0BAU, N1EA, DJ8UB, EW8A, LZ2RS, IW5ELA,PA0PJE, UN8PT, RN4AO, G3UAA, UU7JQ, ON3QA,OK1FAO, DJ0GD, DL3PB, DL9MDW, I2MDI, UA4AES, US5EVD, OK1DXK, W3PO, DL1JGV,OK1KL.

Among them, Sputnik stations are: ON6WJ, W1PID, RN4AO, PA0PJE, UU7JQ, DL3PB, US5EVD. It was a great pleasure, to work in Sputnik days."

Here are two photos of G3MFJ's lovely build. My thanks to George, G3RJV for both passing the "valves" to Graham and sharing Graham's photos with me.

My own Sputnik log of stations worked now includes

Date    Call    His    My    QTH    Notes
7 Oct. ON6WJ     339   239   Belgium   Sputnik to Sputnik QSO!
7 Oct.   ON6WJ     559   559   Belgium   2nd Sputnik to Sputnik
11 Oct.   F6FAI       599   539   France     100w to 43m end-fed wire
11 Oct.   EI5JZ       559   339   Ireland
13 Oct.   ON6WJ    539    229 Belgium   our 3rd Sputnik 2X QSO!

A Sputnik Duet

2011-10-09T08:59:00.000-07:00

Sputnik-party-2011

Results by Peter/DL3PB (rig shown in above photos)

Transmitter: homemade ‘sputnik’ transmitter with 1SH24b/1P24b

400mW out at 90V supply ( 12 x 7.2V/900mAh,
charged with a small solar panel )

tunable from 21.059 to 21.064 MHz

TX/RX relay switch/QSK

Receiver: RX-section of a homemade VXO-QRP-transceiver,
based on trusty ‘Sierra’-design.

Antenna: temporary end-feed vertical dipole on balcony 2nd floor

QSO’s:

Date/UTC/Call/R-RST/S-RST/remarks

4.10   14:50 DJ0GD/p      549 539   Peter/Moers 1W/vertical
4.10   17:37 WA4IUC       349 339   Paul/NC 5W/7el-yagi
5.10 16:49 US5EVD       539 449   Alex 1W/dipole
5.10   17:16 AA1TJ ???    339       Mike/VT Sputnik 400mW/LW*
5.10   18:44 CT4RL/1      429 319   David/Ericeira QRP
7.10 16:16 UA4FCO       559 569    Yuri/Penza 3W/4el-quad
7.10   18:55 CT4RL/1      439 549    David agn 5W
8.10   13:45 CT4RL/1      539 449 ...
9.10   14:52 EA7/G4WZG    559 319    Bern/Malaga 5W
13.10 17:48 K6JSS/4       559 599    Bob/N4BP FL 5W/yagi
14.10 12:44 OH6NPV      419 329    Rauno QRP
14.10 13:00 UA1CEX       239 339    Vic sputnik 1W/G5RV
14.10 14:40 AC4QI         329 439    Jack/Rockmart 80W/7el-yagi
15.10 15:47 W4MQC/1   559 559    NH QRP ARCI Nr. 3788
16.10 12:20 K6JSS/4      559 559    Bob agn QRP ARCI Nr.1
16.10 13:25 K1DPE        559 349    Louis/NH
18.10 15:48 EA4BPN      559 559    Rafa/Madrid 5W/0.5W(349)/GP
18.10 16:05 WV1N         129 219    Bill/CT 1W/80m-dipole
22.10 15:52 RA3DUO     559 579    Boris nr Moscow 150W/loop
22.10 16:34 NS0TA    339 539     contest-style SOTA W2/GC-107

*my report got lost in QRM/QSB, so not a valid QSO

Further my ‘beeps’ were copied by Jim/W1PID
on oct.9th at 13:41z with RST 559 (email)

Hi Peter,

Thank you for the photos of the DL3PB Sputnik! I enjoy so much seeing these little "bare-bones" QRP wonders. And to think that I've heard the signal made from your little handful of parts across the vast Atlantic Ocean. If that doesn't capture the magic of radio I don't know what could.

On Friday you twice hit 539 here. For a short while I could hear both you and Josef/ON6WJ beeping in my headphones at the same time. Your Sputnik "duet" made such a lovely sound...gives Delibes a run for his money ;o)

http://www.youtube.com/watch?v=Vf42IP__ipw

Gently floating on its charming risings,
On the river’s current
On the shining waves,
One hand reaches,
Reaches for the bank,
Where the spring sleeps,
And the bird, the bird sings.
Under the thick dome where the white jasmine
Ah! calling us
Together!

Doucement glissons de son flot charmant
Suivons le courant fuyant
Dans l’onde frémissante
D’une main nonchalante
Viens, gagnons le bord,
Où la source dort et
L’oiseau, l’oiseau chante.
Sous le dôme épais
Où le blanc jasmin,
Ah! descendons
Ensemble!

Cheers,
Mike, AA1TJ