More interesting computer history.
-- Visicalc and importance of spread sheets. (I remember when I first learned to use one).
-- Amazing that the guy who wrote the DOS program for IBM can't get a job today.
-- Sad that the guy who was in the garage with Jobs never got stock options. (Was this ever corrected?)
-- I liked the observation that the most powerful guy in the room is usually the most poorly dressed guy in the room.
I went to bed worrying about this one. John KN6FVK had been having a lot of problems. He had repeatedly reported hearing nothing (crickets!) when he fired up the receiver. Members of the Discord group had provided a lot of coaching, but still, CRICKETS! John had a good sense of humor. When I pointed out that oscillations in the AF amp are caused by a feedback path that meets "the Barkhausen criteria" John said he went to Lowes and bought a spray can of Barkhausen-Be-Gone. It seems to have worked. Actually I think John put some additional capacitance on the DC rail of the AF amp. In any case, he was going to wait for the evening for test out the fixed receiver. The time difference with California meant that I went to bed with fingers crossed. Happily the BBG spray and (more likely) the extra capacitance worked. John sent us some really nice videos of his receiver in action. I really like the inscriptions on his pine board. This should become "a thing."
John writes:
I'm very ok now.... --- sigh / smile --- THANK YOU ALL for your help and patience. As painful as this was, it was a lot of fun and I learned a lot. After I build an actual work bench, I might try this again (looks are important). But I'm definitely going to start playing with it and learning from it. On to Mods and Upgrades! Need to learn-up on this "Barkhausen" silliness too. -73
Join the discussion - SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
It was really cool that our correspondent at FDIM caught up with Eric Schwartz WA6HHQ of Elecraft. Some highlights from the interview:
-- Eric met Wayne Burdick through the NORCAL 40 (Wayne had designed it, and Eric was writing articles about it). That was a very influential rig -- it was the basis for a book and a CALTECH course by David Rutledge.
-- Elecraft has a strong QRP element in its DNA.
-- The K2 is "Heathkit style" and offers the builder the opportunity to understand the rig at the component level.
-- Eric says that using something you built yourself is worth at least 10db.
Here is Bob's interview with Eric:
http://soldersmoke.com/WA6HHQ23.mp3
Thanks Eric and thanks Bob.
Oh no, here's something else for us to worry about when working on old gear. As if the treat of electrocution or radioactive poisoning were not enough, now we have to worry about being hit with a dose of the 1960's drug culture. That could be one bad trip indeed. Imagine if you were having a hard time troubleshooting the Buchla Model 100. All of a sudden things start getting weird and your test gear starts dancing on the bench.
Fortunately, this is not likely to happen with a rig like the DX-100. With rigs like that the only similar danger is nicotine poisoning.
Thanks to Stephen Walters for finding this groovy story.
I was really glad to see that Dave AA7EE has -- after a long absence -- posted another article on his blog. The article has some great personal reminiscences about his involvement with direct conversion receivers. Here is one passage:
I spent many happy hours tuning around and listening on 80M with the DSB80. It was this first experience that cemented my affinity for direct conversion receivers built with commercially available diode ring mixer packages. It just seemed so simple – you squirt RF into one port, a VFO into the other, and (after passing the result through a diplexer) amplify the heck out of the result. The seeming simplicity of the process of converting RF directly to baseband audio has held great appeal for me ever since. Unfortunately, that project didn’t survive. One day, in later adulthood, in my apartment in Hollywood, I reversed the polarity of the 12V DC supply and, discouraged at it’s subsequent refusal to work, tossed the whole thing away. Now, I cannot quite believe that I did that, but it was during a long period of inactivity on the ham bands, and complete lack of interest. If only I could go back, and not have thrown it into the dumpster of my apartment building! Hollywood is ridden with recent notable history. My little double sideband transceiver met it’s unfortunate end just 100 feet from the spot where Bobby Fuller, of The Bobby Fuller Four, was found dead in his car, in 1966, the subject of a still unsolved mystery to this day. The death of my little DSB rig was a lot less mysterious. To think that I heartlessly tossed an SBL-1 mixer into a dumpster, is a mark of how far I had strayed from my homebrewing roots, forged in a little village in England. Now, a few years later, in a city known for it’s sin and excess, I had cruelly ended the life of a stout and honest diode ring mixer. I suppose I should spare a thought for the polyvaricon but, well, you know – it was a polyvaricon!
https://aa7ee.wordpress.com/2021/03/04/the-ve7bpo-direct-conversion-receiver-mainframe/
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