I cringed when, at about the 32 minute mark, during a discussion of the moral necessity of preserving old gear, Michael appeared on the screen with a Heathkit Q multiplier sitting right there next to him. It was as if he was talking about me. I felt as if I had been hauled into Ham Radio Court, Judge Michael Murphy presiding.
I have already REPEATEDLY admitted to sacrificing MULTIPLE Q MULTIPLIERS. But I did it for good reasons:
1) I have some objections to use of regeneration, especially in superhet receivers. After all, Armstrong created the superhet in part to free us from the tyranny of regeneration (that he had also invented).
2) This is a case where the parts ARE greater than the sum. Specifically that variable cap WITH reduction drive. And that perfectly sized metal box. Those capacitors are currently in service in at least two of my homebrew SSB transmitters. And as I look around the shack, I see one of those boxes housing an Si5351 VFO, and another holding the dual-digital frequency displays for my DX-100/HQ-100 AM station.
3) Mike notes that these Q-multipliers are being sold for TWO DOLLARS at hamfests. At prices like this, temptation is just too strong.
So I plead guilty, your honor. But I ask the court to consider the circumstances under which I dismantled this obsolete gear, and the good uses that I made of the parts that I obtained. Also, I'd like to make note of the fact that I salvaged from a junk pile a Heath VF-1 (I completely rebuilt it) AND I restored to usefulness a Heath DX-40 -- both these devices appeared in the WU2D video. Finally, if anyone really needs the remaining parts from the now deceased QF-1s, I'd be willing to donate them (in an effort to redeem myself).
Thanks Mike!
Posts
Mea culpa, Mea culpa, Mea MAXIMA culpa!
ReplyDeleteYour name has been turned into the authorities Armand. This will be on your PERMANENT RECORD.
DeleteJust see what happens the next time you try to renew your license.
DeleteGood luck with that.
73
Steve Silverman KB3SII ... .. ..
1. Regen in the IF of a superhet is different from a regen. Not in principle,but it's fixed frequencyso no adjustment as you tune. It doesn't offer perfect selectivity, but it's useful to morove an existing receiver, and can peak or null as needed. Even in the front end, a q-multiplier can get rid of images.
ReplyDelete2. I used to pull variable capacitors out of broadcast radios lying on the sidewalk, sometimes with reduction gears built in. Sadly that has passed as such radios are less common.
2 There are endless things that get tossed which come in metal.boxes. Maybe not so many that are small. But DVD players, CD players, audio cassette recorders, various set top boxes, PC power supply boxes, I eben once saw someone planning to build a linear amp in a comouter case.
These often provide a switching supply out of the box.
You may need to replace the front panel or cover it up with a metal panel, or blank circuit board works too.
You can make boxes out of circuit board.
I've built things into tin cans.
Scrap consumer electronics often offers tiny enclosures for shielding small sections.
Scrap consumer electronics also offers up parts.
I should have added that a key reason for Armstrong coming up with the superhet was to receive much higher frequencies. So gain didn't have to be on the signal frequency.
ReplyDeleteI'm not sure, but I've seen early superhet schematics where tge IF is RC coupled, showing tgat selectivity wasn't primary. But I've never seen Armstrong's patent so I don't know if his original superhet was rc coupled.