Thursday, September 30, 2010

A New Tunnel Diode Regenerative Receiver


I was excited to find a simple, tunnel diode regenerative short-wave receiver circuit in a book some thirty years ago. Unfortunately, I found the receiver to be practically useless for CW reception. It suffered greatly from intermodulation distortion. The audio distortion was simply awful and to make matters worse, the frequency would injection-lock to any but the weakest of signals. Try as I might, I couldn't improve upon the design. Over the years I have revisited the problem a number of times without any real success. While I've built and operated several reasonably useful tunnel diode direct-conversion receivers, a worthwhile regenerative receiver design has eluded me.

Only, my luck started to change last week, due, no doubt, to an ongoing discussion with DL3PB (thanks Peter!). At last it seems that a simple, well-behaved, tunnel diode regenerative receiver is within my grasp. The drawing shown above indicates the current state of affairs.

On account of their restricted (quasi) linear operating range, I think it's best to keep tunnel diodes out of the signal path as much as possible. This imperative pushed me towards a common regenerative receiver configuration in which the Q-multiplication and product detection functions are performed by separate devices.

My recent experiments began with a negative differential resistance (NDR) driven, LC Q-multiplier. I began by using an adjustable source of NDR. A circuit made of three fixed resistors, a variable resistor and a high-speed op-amp allows one to set the NDR for virtually any desired value. Tunnel diodes, on the other hand, generate what is an essentially fixed-value NDR, depending on the diode specification and bias setting. An adjustable NDR source allows one to simply dial-in, and subsequently measure the value required to drive an LC tank circuit beyond the threshold of sustained oscillation. In this way the NDR required to drive an LC tank, plus the antenna and detector loads can be precisely determined.

Right away I had an old problem reappear. Only moderately strong incoming RF signals were sufficient to pull, synchronize, or injection-lock the oscillator frequency. So long as this happens it's virtually impossible to receive CW or SSB signals. Injection-locking can be seen in phenomenon as diverse as clock and metronome pendulums, fire-flies, cicadas and electronic oscillators. It's a fascinating subject!

Alder's equation tells us that to avoid injection-locking we must: 1) insure our LC tank resonator has a high loaded-Q, and; 2) don't allow the ratio of the oscillator to input RF signal amplitude fall too low.

In order to obtain a high loaded resonator Q we must begin with a high unloaded resonator Q, and then take care that external loading (here; the antenna and detector circuits) is held to a minimum.

Tunnel diode receivers tend to fail the second prerequisite; namely, they work with fairly low self-oscillation amplitudes. A recent experimental regenerative receiver using a back, or backward, diode pointed this out all too clearly. It seemed this minute oscillator signal would frequency-synchronize with nearly every signal to appear within the resonator bandpass!

Conversely, a properly coupled tunnel diode having a higher peak-forward current (Ip) will better resist frequency pulling. I decided that an Ip of 10mA might be high enough to avoid excessive injection-locking, and yet not so high that frequency drifting due to self-heating is an issue. What's more, I happened to have two 1N3718 tunnel diodes in my junkbox. Under typical operating conditions, these 10mA peak-forward current diodes will produce a fixed NDR of 13 Ohms.

I next bread-boarded a 3.5MHz LC resonator along with the coupled antenna load. My adjustable op-amp-based NDR allowed me to determine the number of coupling turns needed in order to drive this loaded resonator into oscillation. I found that a four-turn coupling required an NDR of 369 Ohms. Since my 1N3718 has a fixed NDR of 13 Ohms, it will easily drive this loaded tank into oscillation...in fact, too easily! The resulting oscillation would swing the load-line far beyond the quasi-linear range, thus producing excessive harmonic energy.

I reduced the coupling to 2 turns. This required an NDR of 86 Ohms for the onset of oscillation; a value that's still too high. Finally, a single-turn coupling required an NDR of 26 Ohms. This is high enough to insure reliable oscillator start-up and yet the value is low enough to help insure the signal produced contains little harmonic energy. Replacing the adjustable op-amp NDR source with the 1N3718 tunnel diode produced the desired results. A fairly high spectral-purity oscillation was maintained across the CW portion of the 80m band without having to twiddle a "regeneration" knob...which is a good thing, given that regeneration knobs are hard to come by in a two-terminal oscillator!

As for the results; so far so good! Injection-locking only occurs on strongest of incoming signals. The IMD appears to be no worse than one might expect from a simple, triode or pentode-based regenerative set. The receiver is quiet with low signal distortion. Stronger evening signals can be copied with the headphones lying on the operating table. No SWBCI has been heard in three evenings of operation.

Two nights ago I heard VQ9LA on this setup with a very nice signal. Tonight I copied S59A working VE6WZ; again, with perfectly readable signals. I'll also mention that Mike, WA3SLN, was booming into Vermont this evening with his 75w Heathkit DX-60B and inverted-vee antenna. It's always a pleasure to hear those wonderful rigs of our youth.

Saturday, September 25, 2010

A Bad Augury for Immortality

I suspect most people would agree that immortality (provided such a thing exists) begins from the moment that we come into being. So far as durability is concerned an immortal has no worldly peer; he or she will survive not only bodily death but the end of time itself. The light of immortal consciousness is never dimmed. Once created, it is both imperishable and ever-present.

Only, I don't buy a word of it, and here's why.

In 1979 I was involved in an automobile accident. I'd been a passenger in an old pickup truck that not only had no airbags, it had no seat belts as well. My head smashed mightily into the windshield leaving me fully unconscious for what might have been a minute.

While I survived death that night by the skin of my teeth, I only later realized that it had destroyed any rational hope that I might have for immortality. Immortal beings do not lose consciousness; not for an instant; not for a minute; not for an eternity.

The very concept of immortality stands crucially on the notion that once human life exists a fully functioning body is no longer required for the maintainance of our conscious being. If I were immortal the instant that my brain switched-off, some other means to support my consciousness ought to have immediately switched-on. If this happens to someone so unfortunate as to have been run over by a train or blown to bits by a bomb, it surely ought to have kicked in whilst I was recovering from a knock on the head.

In my case, nothing switched-on until my brain had "rebooted" and come back online. That minute of time had gone missing. It had gone missing no less than the semi-eternity before my birth had passed unnoticed.

It might be argued that some level of brain activity was present while I was temporarily unconscious. Granted. Despite this, my presence-of-self during that minute wasn't worth a damn. This, I attest from first-person experience; or in my case, the lack thereof.

Imagine test driving a car that's advertised as being so durable that it will run flawlessly, and without maintenance, for the next one-hundred years. What credence would you give those claims if the engine quit, and refused to start again for a full minute before you'd even driven the car off the dealer's lot?

Bear in mind, the usual claim is that our immortal consciousness will be sufficiently robust to survive the heat-death of the Universe. But all it took was a smack on the head to temporarily bring mine to a screeching halt. Moreover, I've fallen unconscious twice since my accident in 1979, for reasons far less dramatic than embarrassing.

When I Am Dead, My Dearest, by Christina Rossetti

The philosopher, George Santayana wrote

"The fact of having been born is a bad augury for immortality."

I agree. And yet I think it would be a far tougher case to make if having been born, our lives consisted of a seamless, unflappable stream of consciousness; which is precisely what an immortal ought to expect.

...like any star, I have nothing
to burn but the life I love

William Matthews, E Lucevan Le Stella

Monday, September 13, 2010

The Consolations of Atheism

I disavow all gods, but I'm no atheist. In fact, I'd no more characterize myself as an atheist than I'd exclusively define myself as a nonbeliever in leprechauns or garden fairies. Atheism amounts to a refusal to affirm a specific set of beliefs held by a certain group of people. My denial of another person's beliefs says precious little about the abundant beliefs that are precious to me. Popeye famously asserted, "I yam what I yam." The reason that I am not an atheist is simply this: I yam not what I yam not.

"To say he believes there is no God is inaccurate; he merely does not believe there is a God." Ambrose Bierce, "Prattle," The San Francisco Examiner, Jan. 19, 1890

The characterization of a person by what he or she does not believe may explain a popular notion that says the refusal to affirm religion amounts to nihilism. A hilarious example of this can be found in Steve Martin and the The Steep River Ranger's, wonderful rendition of

"Atheists Don't Have No Songs."

I suspect the joke goes down so well due to the bias (or out of the view that others hold this bias) that whomsoever does not share one's own personal beliefs must lead a barren life. Mildly put, this notion is presumptive and impolite.

A fundamental divide exists in humanity, according to the theists. This divide is made in accord with every man and woman's reaction to their beliefs. They would have us think that our response to their particular set of beliefs stands at the crux of all of our Being; affirmers and deniers alike.

Despite the age-old claims, religion provides no unique insight about the world that we have not imagined into existence. The original sin of religion, so I would say, arose with the early assertion that religious myth is not only spiritually satisfying (which I've no reason to doubt) but objectively true.

Myths, both individual and collective, are the means by which humans introduce value into the world. We live through our myths. We enrich our world by them. Our myths do not explain, they create. They are the means by which we create a home in an otherwise cold and inhospitable universe.

The worth of religion is not determined by its truth or falsity, but by the value we might introduce into the world through it. No less than our poetry and music, our loves, our life itself; the proper question is not whether it is true or false, but whether it is good or bad.

"Humans are caught - in their lives, in their thoughts, in their hungers and ambitions, in their avarice and cruelty, and in their kindness and generosity too - in a net of good and evil. I think this is the only story we have and that it occurs on all levels of feeling and intelligence. Virtue and vice were the warp and woof of our consciousness, and they will be the fabric of our last, and this despite any changes we may impose on field and river and mountain, on economy and manners. There is no other story. A man, after he has brushed off the dust and chips of his life, will have left only the hard, clean questions: Was it good or was it evil? Have I done well - or ill?"
John Steinbeck, East of Eden

I would like to acquaint you with a beautiful paper written by Peter Simons, Professor of Philosophy at Dublin's Trinity College, entitled, The Consolations of Atheism. The paper is available here.

Cheers,
Michael

Wednesday, September 8, 2010

Verweile doch, du bist so schön!


I came across a strange and wonderful thing whilst visiting a clock and watch museum in Vienna some years ago. It was a tiny pocket watch made almost entirely from wood and other organic materials. I nearly fainted on the spot.

I've since learned from my reading that these precious jewels were made in the Urals (Wjata-kirov) by H.S. Bronnikoff & Son; circa 1850.

The 51mm diameter case is made of birch-root. The wheels are made of palm wood. The dials and hands are of honeysuckle. The cartouches and some of the screws are made from bone. The balance spring is made from (then expensive) steel. The mainspring in this watch is reportedly made from bamboo; although other examples from Mr. Bronnikoff's shop used steel.

"The most powerful drive in the ascent of man is his pleasure in his own skill. He loves to do what he does well, and having done it well, he loves to do it better. You see it in his science. You see it in the magnificence with which he carves and builds, the loving care, the gaiety, the effrontery. The monuments are supposed to commemorate kings and religions, heroes, dogmas, but in the end the man they commemorate is the builder. " Jacob Bronowski, Ascent of Man

Benediction

“For the past eighty years I have started each day in the same manner. It is not a mechanical routine but something essential to my daily life. I go to the piano, and I play two preludes and fugues of Bach. I cannot think of doing otherwise. It is a sort of benediction on the house. But that is not its only meaning for me. It is a rediscovery of the world of which I have the joy of being a part. It fills me with awareness of the wonder of life, with a feeling of the incredible marvel of being a human being. The music is never the same for me, never. Each day it is something new, fantastic and unbelievable.”

Pablo Casals, “Joys and Sorrows”

Tuesday, September 7, 2010

Non Plus Ultra of Identity Theft


This popped into my head the other day whilst I was vacuuming the floor.

"And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him." Revelations 12:9

If the above passage is correct then every historical detail associated with God is suspect. If this passage is true then none can say whether the author of the Bible is God or Satan. If such a great and powerful Deceiver truly is afoot in this world, it's reasonable to expect that He would attempt to hijack the identity of God as the ultimate act of deceit. So long as we know this, we can never know whether Judeo-Christians worship the (supposedly) genuine God or His impostor.

For example, the Book of Exodus tells us that an angel of Yahweh appeared as a burning bush. In the light of my vacuum-cleaning revelation, I submit that we have no way of knowing whether it was an angel of Yahweh or an angel of Satan. And how did Mary know it was the angel, Gabriel, that appeared to her at The Annunciation? Did she ask to see a badge? How did she know it wasn't an angel of Lucifer instead?

If, as the Bible tells us, we have a deceiving Devil in our midst, then we have no way of knowing the limits of his deceptions. In this case we should rightfully expect that some, or all, of everything that has been historically attributed of, and to, the "true" God may be a hoax. No matter that the clouds should part and an almighty voice is heard to thunder; we simply have no way of knowing whose voice it is that we are hearing. Any identity paper that God could flash, the Devil could forge. If both God and the Devil are supernatural and eternal beings endowed with the ability to present themselves in any form, how could a mortal begin to sort them out?

Voice: "Fall on your knees, for I am your Lord!"

Mortal: "Um...how do I know you aren't the other guy?"

Voice: "Because I'm telling you that I am."

Mortal: "But wouldn't the other guy say that?"

Voice: "Well, I can walk on water."

Mortal: "If Satan can turn himself into a snake, betcha he can walk on water too."

If the Devil is a supernatural being accustomed to crossing swords with God Himself; on this scale, what chance do we have at seeing through his elaborate deceptions? Inasmuch as Christians can't even agree on the central tenant of Christianity itself, how could they begin to untangle a Satanic ruse enacted on a titanic scale, preceding the dawn of time itself?

Some time ago, I heard one of those evangelical preachers at the television station where I work. He was on about not allowing the Devil to lead you away from God's word. What he fails to grasp is that it would have been child's play for the Devil of his myth to ensure that we have never heard as much as a letter of God's word. He summons this Devil and then vastly underestimates its abilities. And he surely doesn't appreciate that introducing a Devil into his myth opens a "Pandora's Box" from which his myth cannot escape. His myth becomes a serpent that consumes itself.

The Devil could present himself as a handsome and soft-spoken man wearing a white gown. I can imagine a tableaux wherein he is seated with a lamb on his lap with a hallowed, virgin-mother beside him. He could speak any number of gentle platitudes. He could promise us all sorts of wonderful things; an eternal life of beatitude, absolute justice,... and he could string us along like this for thousands of years (what's a millennium, give or take, to the Devil?).

If you don't believe that a benevolent God would stand by and let this happen, where, for example, was this benevolent God in 2004, as 230,000 men, woman and children were swept to their deaths in the tsunami? Where was his loving hand to be found when the devastating Sichuan earthquake of 2008 dropped entire buildings on the heads of hapless, Chinese school children? At a minimum, it appears as though He is a "hands-off" kind of deity. The Devil, in contrast, might-well take a "hands-on" approach.

My thesis is that so long as we accept there is an enormously powerful devil at large, we cannot know whether the Bible is the word of God or the work of the Devil. In the latter case, it would scarcely make sense to attempt to shed light on the matter by consulting the Devil's own handiwork. The true God (provided such a thing exists) may have chosen not to reveal Himself to mankind thus far. Satan could have decided to fill this void with his own message. Michelangelo's image of a wise man with a gray beard, Moses' stone tablet bearing the Ten Commandments....every bit of this lore may be part of the Devil's ancient and vast conspiracy to deceive us. I should think that any devil worth his Sulfur would be hell-bent precisely upon this task.

In which case, wouldn't the Devil loathe the very questions that I am raising? This business of elevating blind faith and belief as the paragon of religious virtue may be right out of the Devil's playbook. Wouldn't the Devil be the first to command us to not ask questions, but simply to believe?

It's my contention that once you admit there is a powerful, supernatural force bent upon deceiving you, "all bets are off" so far as identifying the authorship of any bellowed voice or handed-down scripture. In a world comprised of every example of good, evil, noble pleasure and horrific tragedy, there is no seal of authenticity that a Lord might use to identify Himself from a lessor rival intent on mischief on a massive scale. No matter how seemingly benign, every command becomes suspect.

IZ0PEC de AA1TJ/QRPp


Dear Fabio,
Thank you for your patience in copying my signal on 20m CW this evening. I had been calling DX stations for several hours but you were the only one to answer. My homebrew rig has an output power of only 10mW (0.010 watts). The distance between us is 8793km; nearly one million km per Watt! The antenna here is simply an end-fed wire.

I am amazed that you heard my 10mW signal in Rome. It's fantastic!

Again, thank you for patiently listening for my weak signal, OM. It would not have been possible without your very kind efforts.

Ciao,
Mike, AA1TJ


Dear Michael,
Many many compliments for your QRPp station! Really exciting to have QSO in this conditions... It's actually the first time I can connect QRPp oversea... Unbelievable, something we can tell our friends forever!!!

I was transmitting with 4 el antenna and something more than 100w.

I will have to take back my 817 and try to call DX as you bravely did!!!

Best 73 QSL
Fabio de IZ0PEC

The Witches of Africa


Exodus 22:18 "Thou shalt not suffer a witch to live."

Let's suppose that Bible readers have misread this ancient passage. Let's suppose the author of this book never intended that His readers should view this as a directive to seek out and murder those whom they deem to be witches.

Only, that's exactly what people have done. They've murdered innocents by the tens of thousands. It continues to this very day. The perpetrators of these bestial acts point to this passage, among others, in order to justify their behavior.

My question is; "Would not an omniscient God have known this in advance?" And knowing how this passage was going to be interpreted, would not this same benevolent God have made some minimal effort to insure that this passage would not be so interpreted? If it is, presumably, His word, He could have written anything He wished. So why? Why this horror?

"Over the 160 years from 1500 to 1660, Europe saw between 50,000 and 80,000 suspected witches executed. About 80% of those killed were women. Execution rates varied greatly by country, from a high of about 26,000 in Germany to about 10,000 in France, 1,000 in England, and only four in Ireland. The lower death tolls in England and Ireland owe in part to better procedural safeguards in those countries for defendants."

http://www.law.umkc.edu/faculty/projects/ftrials/salem/witchhistory.html

By comparison, the widespread rape and abuse of children by clergy of the modern-day Catholic Church seems like...

Like child's play?

http://www.youtube.com/watch?v=zbDu0-K9cPk
http://www.guardian.co.uk/world/2007/dec/09/tracymcveigh.theobserver
http://www.nytimes.com/2010/05/22/us/22beliefs.html


"...religious fundamentalists and fanatics incarcerate women, mutilate genitals, amputate hands, murder, bomb and terrorise in the name of their faith. It is a mistake to think that our own milk-and-water clerics would never conceive of doing likewise; it is not long in historical terms since Christian priests were burning people at the stake if they did not believe that wine turns to blood when a priest prays over it or...whipping people and slitting their noses and ears for having sex outside marriage…" “Don’t Leave Morals to the Madmen” A.C. Grayling, The Guardian, March 22, 2000

Antonio Porchia


These are some of my favorite aphorisms from the wonderful man, Antonio Porchia. These are taken from his, Voces, which appeared in 1943. I gather the first English translation came in 1968. Some of you may remember that I quoted Porchia for my mother's eulogy.

"When I do not walk in the clouds I walk as though I were lost."

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

"He who does not fill his world with phantoms remains alone."

"I know what I have given you, I do not know what you have received."

"When I die, I will not see myself die, for the first time."

"My poverty is not complete: it lacks me."

"Man, when he is merely what he seems to be, is almost nothing."

"I have found the most beautiful side of the flowers in the fallen flowers."

"You are always telling a dream. When do you dream it?"

"Every time I wake, I understand how easy it is to be nothing."

"The dream which is not fed with dream disappears."

"More grievous than tears is the sight of them."

"If those who owe us nothing gave us nothing, how poor we would be."

"Beyond my body my veins are invisible." (How I love this one...)

Monday, September 6, 2010

Is Our Life Merely A Test?


A commonly raised objection to Christian dogma asks why an omniscient and supra-benevolent God would create, for example, the murderer of a child. For verily, an omniscient God could clearly foretell every gruesome detail of the child's ensuing murder before He had even created the murderer. So why would a benevolent God go ahead to create and unleash a murderer upon the unsuspecting child?

The usual answer offered by Christian theologians is that God is far more interested in vesting His human creations with a free will than in preventing (in this example) the murder of children. The Christian response typically goes on to tell how it is only by breathing a free will into us that God determines whether each of us is individually deserving of either eternal salvation or eternal damnation. Earthly life, they insist, amounts to a test administered to each one of us by our Creator.

Consider the case of a sixty year-old man that murders a one year-old boy. Obviously, the man has failed his test, but what about the child? Inexplicably, the little boy was not allowed to take God's test. He wasn't given the opportunity to develop and utilize his own free will. And to those who would argue that the murdered child goes directly to heaven, I ask, "Why?" If the boy had been allowed to grow up he might have become a murderer himself, in which case he would have gone to Hell. Or, he might have eventually turned into another, Albert Schweitzer, thus pocketing his one-way ticket to everlasting Paradise. But in allowing the sixty year-old murderer to carry out his grisly crime, God is deprived of the opportunity to judge which path the one year-old boy would have chosen had the lad been granted a full, earthly life.

Someone might object that God does know which path the boy would have taken, because God is omniscient.

Not so fast. A God so benevolent as to bestow his heavenly reward to a murdered child on the basis that God knew how that child would have acted, had it been granted a full life, is a God that would condemn the sixty year-old murderer to hades before the child was actually murdered. A God that waives murdered children through the Pearly Gates before they've completed their earthly, free will-based admission exam, is a God that has just forfeited His argument that He has no choice but to allow murderers to kill before He may pass judgment on them.

A way around this dilemma would be for God not to admit murdered children into Heaven. Well then, what's to be done with the souls of murdered children? God could simply make them vanish, or perhaps God could pop their souls back into another womb for a "redo." And yet if he actually took either of those two options then it would turn out that our benevolent God creates children and then allows them to be murdered just so He may be justified in sending their murderers to hell. These children, it seems, were not given life in order to show themselves worthy of their own salvation. Rather, their short lives amounted to mere "props" in their murderer's test for salvation. Here, we would rightly conclude that only some of God's children are allowed to take His earthly test, while other of His children are created in order that those who were allowed to take the test - and subsequently failed in the worst way - had a warm neck to strangle or a beating heart to stab.

"Father Paneloux: 'Perhaps we should love what we cannot understand.' Riex answers: 'No Father. I have a very different idea of love. And until my dying day I shall refuse to love a scheme of things in which children are put to torture.'"
Camus, The Plague

I wish also to raise the larger question concerning God's supposed test. Imagine that you sat for an examination along with a large number of other persons of your age. Imagine further that this examination alone would determine whether you would be admitted into the university or whether you would spend the rest of your life shoveling shit in Siberia. Now suppose that the examination paper you were handed had to do with the intricacies of quantum physics and yet you noticed that your neighbor's test consisted entirely of 4rth-Grade arithmetic problems. Would you question whether or not this amounts to a fair test?

Now consider - not imagine, consider - that some of us are born with the proverbial silver-spoon in our mouths while others are born and raised in squalor. Some of us live long and charmed lives; never knowing war or debilitating disease, while others are born with physical or mental birth-defects. Some must battle alcohol or drug addictions while others can only wonder what it would be like to be saddled with such an affliction.

If this life truly amounted to an unbiased test given by God in order to assess the goodness of each individual's free will, then each and every human being ought to be born into identical conditions and with identical mental hard-wiring. We often hear it said that, "Life isn't fair." I agree that life isn't fair. And this fact alone delivers a knock-down argument to debunk the myth that our life is but a test administered to us by a benevolent, loving and unbiased God.

Pieta


"A non-Jewish doctor, Ella Lingens-Reinert...was sent to Auschwitz for harboring a Jew in her home in Vienna. As a non-Jewish prisoner, she had a privileged position and was respected even by the SS women. One day she was standing with an SS woman whose husband also worked at Auschwitz, watching a long line of children, women and old or incapacitated men waiting in front of a gas chamber. She asked the SS woman, "Do you like working here?" "No, Frau Doktor," answered the woman, "I don't really like it."

"But then why do you do it? You could be transferred if you wanted."

"Yes, but you see, it's like this. My husband and I both come from very simple families, we are hard-working people, and for many years we have been hoping to live in a better area. We want to have pleasant and respectable neighbors and friends. It is only now that we have been able to buy a house in a nice suburb. It is almost ready, but the kitchen is still far from finished. If we work here for only six more months we can have it finished....Then we will stop working here."


George Klein, Pieta

Moral Luck


"In 1967 a military coup in Greece installed an incompetent but ruthless junta. For the next seven years the government attempted to maintain itself in power through the use of torture. Youths were selected (not on the basis of their sadism) from the regular army and subjected to months of brutal training in which they were beaten and humiliated. At the end of their training they were given uniforms and suddenly treated with respect. They were the new security police and they were expected to torture and murder. Almost all of them did so. When the junta failed many of these men were arrested.

But it wasn't their fault that they had been selected. They were no better or worse (apparently so) than anyone else. The fact that nearly everyone chosen went on to torture and kill tells us that anyone of us might do the same if we had been selected. So, how could we judge a man for something we probably would have been guilty of? Aren't we blaming them for being unlucky enough to have been at the wrong place at the wrong time?"
Piers Benn, Ethics

Most of us can remember past situations in which our negligence might have resulted in a tragedy. For example, I once set my little brother on fire in a "chemistry experiment" gone awry. Only his heavy winter overcoat saved him from having been badly burned. At summer camp, I once shot an arrow just over a target and struck a young woman (standing behind the target) in the arm. Had I aimed that arrow a half-a-degree further to the left I would have buried the arrow in her heart. While driving I've often taken my eyes off the road to retrieve something that had fallen under the seat, etc. Had a child just so happened to cross in front of my car while I was looking down, well...I doubt if I could today live with my guilt.

Kant says that in each of these cases my culpability doesn't rest with the contingency of the situation. He'd say I had a duty to: keep my brother away from that container of flammable acetone, to look behind the target before I loosed my arrow and to always keep my eyes on the road. It's clear that in each of these cases I failed in my duty. Should I go out to the barn and hang myself because of what I might have done? Thomas Nagel wrote:

"If one negligently leaves the bath running with the baby in it, one will realize, as one bounds up the stairs toward the bathroom, that if the baby has drowned one has done something awful, whereas if it has not one has merely been careless."

The element of luck is never entirely absent from our lives. In his book, Being Good, the philosopher, Simon Blackburn, wrote:

"Luck can do more to sway the ways our lives go than virtue. Yet people are curiously unwilling to acknowledge this; we relentlessly take responsibility, as the myth of original sin shows. It seems we would prefer to be guilty than unlucky.... If we are good, it may be because we were never tempted enough, or frightened enough, or put in a desperate enough need."

How can we reconcile the the need to hold individuals responsible for their actions at the same time we realize that so much in our lives depends upon luck (or chance)?

Pragmatic pressures impel society to treat each constituent member as if he or she were an independently responsible moral agent. However, to be forced to accept a belief for the good of something else does not imply that the belief is true. As Isaac Bashevis Singer wittily noted:

"We have to believe in free-will. We have no choice."

I will oppose any suggestion that men should not be held personally responsible for their actions. Nonetheless, I also believe we need to be aware that this pragmatic belief is little more than a convenient lie. And as Tolstoy tells us in the last line of War and Peace:

"It is necessary to renounce a freedom that does not exist and to recognize a dependence of which we are not personally responsible."

My wife once heard a story on National Public Radio about a woman who struck and killed a small boy with her car while she was herself quite young. Despite the fact that she was judged not to be at fault, this woman said that a day does not go by that she doesn't think of the boy she killed. She thought of him on her wedding day, she thought of him when her first child was born, and she expects to think of him on the day she dies. She was in the wrong place at the wrong time.

But weren't those young Greek soldiers in my above example, also in the wrong place at the wrong time? It's true that they could have rebelled against their training. But the fact that almost none did rebel must be telling us something about ourselves in general. What makes us so certain that we wouldn't do the same if placed in a similar situation? For example, how long would you withstand torture before you gave away the names of your friends and loved ones? I'd like to think that I'd die rather than give up the names. But how could I know, sitting here in my comfortable chair, what I'd do with high-voltage wires attached to my testicles? With luck, I'll never have to find out what I would do under those circumstances. Kant writes in his Metaphysical Elements of Ethics:

"And how many there are who may have led a long blameless life, who are only fortunate in having escaped so many temptations."

Precious few Volk living in Nazi-Germany chose to stand in front of a firing squad or endure life in a concentration camp rather than become part of the machinery of a wicked government. If you think of Nazi-Germany as a vast moral experiment, the results suggest that nearly all of us today would have done exactly the same. The only reason most of us can point an accusative finger at them is that we were lucky enough not to be born in similar circumstances. The same can be said of the Greek conscripts turned-torturers. How many examples do we need in order to conclude that most nominally good men will commit horrible crimes if tempted enough, frightened enough, or desperate enough?

"First comes eating, then comes morality." Bertolt Brecht

I believe that criminals must be isolated from the general society. However, one of many reasons that I believe we ought to treat criminals mercifully has to do with the fact that they may have acted no worse than you or I, had we been born, raised and lived in their circumstances.

The Gridless Gammatron

The Gridless Gammatron (GG) was developed in the late 1920's by Ralph Heintz (an engineer/ham from Berkeley, CA), as a means to tell RCA's David Sarnoff and his army of lawyers to "go stuff it." Instead of the usual coaxial grid, Heintz' GG employed a control, or "gamma" electrode placed opposite the cathode and anode, such that it could modulate the cathode space-charge. These fire-bottles used a pure tungsten "bright" emitter along with tantalum anode and control electrodes.

Heintz threw in with a pal, Jack Kaufman, to form the H&K vacuum tube company. The early GG's were used primarily in the high-powered transmitters that made up the communication network for the Dollar Steamship Co. Pacific Ocean fleet (Dollar owned a sizable portion of H&K). However, Heintz was pleased to sell his GG's to hams, so long as Dollar's electron tube needs were met first. They certainly did the job, only, the GG electrode arrangement never amounted to more than a "poor cousin" to the conventional triode. H&K stopped making theses GG's as soon as the RCA "Patent Police" had been called to heel. BTW, H&K continued to call their conventional gridded tubes "Gammatrons," which can be confusing as not every Gammatron is of the gridless variety.

Searching for info on the unusual Russian sub-miniature vacuum tubes that I'd been using, I came upon this link. About halfway down the page I suddenly began reading about Gammatrons.

Well, you know how it is...now I'm off and running on Gridless Gammatrons. Right away I came upon mention of a series of articles that recently appeared in, The Tube Collector.

  • Volume 6, #2, April 2004, "The 6AX5 Gammatron Amplifier/Oscillator
  • Volume 8, #1, February 2006, Working Transmitter Using the H&K Gammatron Principle using 6X5WGT Rectifiers
  • Volume 10, #6, December 2008, Tests on the 6X4W Tubes for Gammatron Operation

While I haven't yet read any of these articles, I gather these guys have figured out that the internal geometry of certain full-wave rectifier vacuum tubes could be used to mimic the old H&K GG structure. It's not a perfect match; for example, H&K placed their control electrode much closer to the cathode, whereas the FW rectifier anodes are equi-distant from the cathode.

I unearthed a sleeve of 6X4 rectifiers from my subterranean parts storage vault. Having climbed back up to the workbench I donned a strong optical magnifier. Rats! the 6X4 FW rectifier uses a pair of coaxial anodes. A Gammatron needs a pair of parallel anodes. Back in the vault I noticed two "Tung-Sol" brand 6X4W rectifiers in my box of tubes. One look through my magnifiers told me that I had struck "Gamma Gold;" I had my parallal anodes.

The first circuit I tried was a variation on John Sousa's (author of the Russian valve link shown above) AM broadcast-band oscillator. I used a 455kHz transistor IF transformer. My reading told me that it was important to reduce the energy applied to the heater in order to create a more diffuse electron space-charge around the cathode (a saturated space-charge is more "opaque" to the electrostatic field created by the control electrode). I checked my connections and fired everything up.

Nothing...as usual. These sorts of experiments almost never work right off the bat (you have to suffer a bit first :o)

Trying different ideas and varying the various circuit parameters, I happened to switch off the control electrode B+ pull-up bias just before switching off the bias to the anode. For a fleeting instant I saw something that looked like a 30 degree segment of a sinusoid on the scope. Working backwards, I found that the multi-MegOhm bias resistor should be returned to ground instead of B+. Wow...there it was...a gorgeous sinusoid at 400kHz. My GG was alive!

I spent the remainder of the evening trying to fashion a LF regenerative receiver using my new GG circuit. The best I could do was an inefficient heterodyne direct-conversion receiver. I copied one Canadian LF beacon (YWM, Maniwaki, Quebec) as well as a couple of strong stations sending digital data. In retrospect, I think my problem had to do with the lack non-linearity required for efficient mixing/detection.

I did notice that my oscillator signal strength was an inverse function of the frequency; most likely due to excessive electrode capacitance. I figured that's the reason all the chatter I've seen concerning those The Tube Collector articles was centered around the AM broadcast band.

Consulting with the Great Feathered Oracle (my pillow) that night, I decided the problem must be the control-electrode to anode capacitance. At least for narrow-band work, I reasoned that an inductor, or the inclusion of a complete LC resonator, might be used to cancel/absorb this offending feedback path. To my knowledge, no one (at least recently) has used a GG in a quartz crystal-controlled oscillator. It seemed the Pierce configuration ought to have the best chance of absorbing the stray feedback capacitance.

I wired everything up and Lo!...the Pierce xtal oscillator worked just fine; at least at 507kHz. Since I was using an RFC as the anode load it was simple enough to slip in crystals of ever higher frequency.

1.2MHz, yup.

3.58MHz, check (getting excited now)

7.0MHz, still okay

14.0MHz, yes, believe it or not

28MHz, no dice, but not too disappointed!

I put the 40m rock back in and replaced the RFC for a link-coupled LC tank. Working into 50 Ohms, the highest output power seen was 1.7mW.

The next day I found that it was possible to raise the RF output to just over 3mW; this, with a DC plate current well within the published maximum ratings.

That's when things began to go South. I began to notice the output signal level was slowly fading. With hindsight, I ought to have pulled the plug right away. Instead, I fussed about in hopes of discovering what was happening. Well, I continued to fuss and as I did I watched the output signal gradually bleed away to nothing. In fact, my 6X4W was now Fin, Morte, Tot...

Here's what I think happened.

The 6X4W cathode is oxide coated. It's not a pure tungsten (bright) emitter such as was used in the original Gammatrons. In order to mimic Gammatron behavior it's necessary to run with a cathode temperature well below the specified rating. In fact, I'd been driving my 6X4W heater with only 4Vdc @ ~400mA in order to produce a more diffuse than normal electron space-charge at the cathode.

I'm uncertain whether the failure mechanism involved was "so-called" cathode stripping or cathode poisoning. However, I'm confident that it was the lack of proper space-charge protection that resulted in the permanent loss of cathode emission.

I have one 6X4W remaining in my junkbox. Once conditions on the 80m band have become more favorable for QRPp operation, my plan is to fire it up in the "Gammatron Mode" while holding the output power well below the maximum possible level. I think it might be best to run the 6X4W in this way just long enough to complete a pre-scheduled QSO or two; just enough to say that a Gridless Gammatron has once again ridden the ham bands.


Some further references on Gridless Gammatrons

http://www.tubecollectors.org/archives/HK255.pdf
http://www.tubecollectors.org/archives/hkprice36.pdf
Radiomuseum; Dual Plate Triodes Review