The Radio Gods seem to be pushing me towards Direct Conversion receivers. This week I was speaking via Zoom with the very FB L'Anse Creuse Amateur Radio Club in Michigan. My Herring Aid 5 tale of woe came up (see video above). Then Dean KK4DAS was sharing video of the amazing fidelity of the Pete Juliano Direct Conversion Receiver. Then I started thinking about Frank Jones W6AJF, and the story (fictional) of his build of the Herring Aid 5 by Michael Hopkins AB5L:
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I gave Frank a board for the Herring Aid Five redux from the April 1998 QRP Quarterly and challenged him to build one up. It took maybe two hours and that includes his own touches which included refusing to buy any parts.
For the transformers, he calculated the turns ratios from the impedances and tested a bunch of TV set pulls 'till he found something close. But he made the output 1:1 because his Brandes phones are close to 1000K Ohms as it is.
He was willing to use toroids, but not to buy one, so I gave him an Amidon circular and he calculated the values of the 18 specified units. Then he wound them on unidentified cores from my junk box after learning the permeability of each with his homebrew dip meter.
A store bought Zener was out of the question so he mixed and matched regular diodes with transistors hooked up as diodes until he got close enough to 10 volts. The mosfets came out of a TV tuner and Frank will use any plastic bipolar that says "C" or "D" on it for a 2N2222.
Of course it worked the first time. He rigged up a patch to a pair of Class A push-pull 6L6s so Christie could hear it and she said it was "Also cute but bigger than the other one."
Now a real QRPer would cry at that, but not Frank who sees no advantage in miniaturization at all. In fact, he mounted the whole thing in an old case from a Collins 6 and 2M transceiving attachment he junked out for the parts and no two knobs matched as Frank thinks matching knobs slow you down in a pileup. He wanted to take it back to his own shack and try it out with his breadboard MOPA and pair of 100THs because he does not run QRP, saying it "transfers the burden to the other guy."
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Frank Jones was one HARD CORE HOMEBREWER. No store-bought Zener diodes or toroidal cores for him!
All of the SolderSmoke Herring Aid 5 articles can be found here:
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