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Saw more than a few that had the low-profile heat dissipators on the plate caps, and a hole cut in the shield cover above each tube. The painted top cover would have a gap above the the tube cap sufficient to avoid arcs. Just can't use a heat dissipator that's taller than the tube's plate cap...

The difference is too small to worry about. People who obsess over a 15 or 20 percent power difference are impressed. But the S-meter at the other end of the conversation won't move more than the width of the pointer if that much. My practice has been to use the 1969 and not worry about a...

Some, but not all. 73

Must be getting old. Remembered this request as Uniden Washington. Yeah, same circuit board. Didn't find one picture of that procedure for that model. Did find the text file that got handed to a new tech. Here's the setup for that radio. Pretty sure the wire colors are the same. Find the wire...

Way cool! That radio had a devoted following 50 years ago. That was the era of "sideband clubs". Each one had a 'home' channel above channel 23. The AM operators considered them snobs. The console II is capable of excellent transmit audio when it's right. Pretty sure we ditched all the...

Darn well ought to. Reducing base bias to the mike amp is a lame way to control audio gain. 73

These folks have the genuine HG components. https://www.icamanufacturing.com/shop/p/hg-2sc1969 73

It's simpler. One diode comes loose, one resistor gets removed and one wire gets moved. My bedtime right now. I'll check back with the details later. 73

Sometimes it is. Especially when poopy audio is the issue. Just one problem. There's only one way to find out. Change them all and compare before audio to after audio. Or you could trace through the audio circuits, one capacitor at a time and identify the ESR for each. Replace the ones that...

So, how much did it drift before? Is this only a transmit-side problem, or does it drift on receive as well? All this mod does is to unook the fine control from the receive-only power source and connect it to the same one that powers the Coarse control. Any chance the clarifier only needs...

Pretty sure the chatroom thread he started concerns a Dentron GLA1000 that won't key. Unless this amplifier has been modified, you need either a foot switch plugged into the socket marked "relay" on the back panel, or a radio that has a linear-keying relay inside it. The GLA is a ham linear, and...

The "B" version of the tube is what the factory built it with also called 7034. The heater is rated at six point zero Volts, not 6.3. There are variations. The 4CX250R/7580 will deliver more power, but requires more negative-bias voltage to control it properly. The DX300's blower really isn't...

Way cool! I still have that LP. Somewhere... 73

I sell a pc board that simulates a zener with a string of forward-biased rectifier diodes. Has the advantage of being a bit less fragile than a zener in the face of a surge current. Its main appeal is to AM operators who ignore the factory's advice to select "CW/Tune" to operate AM. Cuts the...

This is where a 'scope pays for itself. Watching the tuning voltage while you flip from channel 1 to 40 and back lets you make sure the voltage is well within the max/min limits, once for receive and then for transmit. A VCO with its slug set to 'almost' cover all 40 can buzz on a channel that...

Wow! It's about time somebody did it that way. A long, long time ago I wanted to find a way to do that in hardware. The "Lamb" blanker every Cobra and RCI SSB CB uses does this in the amplitude domain. I wanted to do it in the frequency domain. Never found a way. Bravo Elecraft! 73

A customer brought in one of Lou's 6-meter SB220s. Didn't quite know what he had bought, except that it looked slick. Wants it converted to 10 (cough) meters. He's still a few stops back up the pipeline. When it happens, I'll share some pics. Here is Lou's website for his conversions...

That sure works in your favor. Seems to me there's a 12-pin "compactron" tube in there, maybe a 6C10 that has three triodes in it. Saves space, but that one has gotten expensive. Turns out to have been used in some high-end guitar amp of the 60s. I used one of these decades ago. Decided to set...

The Bird 43 has a hole on each side meant to hold two spare elements. Those holes are empty on mine, with all my elements in a rack on the bench. The end of the monitor radio's coax jumper just hangs inside that hole. Enough RF leaks out of the pickup section to overcome the transmit RF leaking...

He was a puzzle thirty years ago as "Professor" on rec.radio.cb. Doesn't seem to have changed a lot. 73