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Not fond of roller inductors. They seemed sexy when I was young, but they are nothing but a maintenance headache. Hmm. Sexy = high maintenance. Been there. Variometers are used in the tuning unit at the base of AM broadcast towers to compensate for seasonal influences on antenna tuning...

I tried posting a link to a post I made a while ago. Some of the pics were missing. No idea why, and I can't edit a post that old to fix a hyperlink. So here's another try: Here is a procedure we have done so many times that a written description just never got made. Kinda like folklore...

A "glitch" resistor in line between the HV + and the anode choke does serve to place a current limit on a short pulse, like an arc inside a tube. If it's short enough, the resistor will survive. And if the fault current lasts long enough to pop the resistor, it still served to protect other...

The Lightning quad antennas using the "SFS" feed method connect the coax braid directly to the boom. The back-country Lightning clone on my tower is built that way. 73

That's caused by error in the 10.24 MHz crystal. Early 40-channel CB PLLs had a trimmer on that crystal, along with the heterodyne and carrier crystals. No 40-channel CB made since 1980 or so has a separate adjustment for that. Guess they decided that feature doesn't pay for itself. 73

This affects only the meter. It bypasses the mode selector. There's no 'modulation' measurement in sideband modes. Just serves to prevent meter damage if/when the mode selector suffers the most-common sort of breakdown later on. We've seen too many Mark 3 SSB meters hammered when the mode...

Needs a monostable multivibrator. Commonly called a "one-shot". More than one way to do this, but it's bedtime. Film at 11. 73

An incandescent bulb for a transmit light? Not a switch, but definitely on the other end of a wire. 73

Rock on! That's the result you're looking for. 7.8 MHz is definitely not on the list of types I have. We have seen coil forms with two different turn pitches. Never kept a record of which was used in which models. Haven't seen a version six in quite some time. All of them we ever bought got...

The pins on those switches are incredibly delicate. If a pin is folded flat against the foil pad be very, very gentle prying it up to unsolder and remove from the pc board. They break off way too easily. No need to ask me how I know. 73

Pretty much any Uniden SSB CB with the 8719 or 8734 PLL uses the same selector. Counts from binary equivalent of 16 to 61. The LED display hookup is the same for all of them. If memory serves, the type numbers are SR208 and SR209. Only difference between them is the shaft length. Some but not...

I insisted the boss buy a HP counter when he opened our shop in 1975. Used a 5381 every day for almost 40 years before it finally broke. By then we had other lab grade counters and it got retired. We calibrated it by "leaking" the counter's clock crystal out to the antenna of a receiver set to...

Actually this might work better with an AM modulated tone. When you switch from AM to one sideband, you'll know you're on frequency when the tone pitch is exactly the same from AM to sideband. Much easier than trying to hear a true zero beat. That's how we set a receiver to WWV. 73

The solder pads that look like an open-end wrench are for external wires. As if some additional switch or control was connected there. Don't know what for, though. 73

Might be quicker to just build your own. The schematic is in the post below, along with a wiring diagram using an obsolete chip. Should be possible to build it with three NPN transistors, but I haven't tried it...

I have never tried to trace out what those parts would do. Was it a feature left out? Or a feature that didn't work out as intended? Somebody ought to draw up what those missing parts connect to. Sometimes my lack of curiosity can be apalling. 73

Good luck with that. The wiring is different for the 23 MHz version. This is just too high a frequency to be stable with this design. The version 6 tends to drift whether you tweek the negative tempco caps or not. The published schemo makes no mention of a "6" at all. To start, the max...

Reel tape decks came in two basic types. Two head and three head. Naturally, the two head setup was cheaper, using one for erase, and one for both record and playback. A three-head deck had one for record only and one downstream from it for playback only. The delay from record head to play head...

RG59 has copper braid. That's what we have used. Haven't made a co-phase harness in decades. Found that a half-wave long 50-ohm jumper between the radio and the harness made amplifiers behave better. SWR meter didn't reveal why. And affordable analyzers were still years in the future. 73

Used to have a box with a spring reverb in it. Went in line with your mike. Sounded terrible. I guess that was the idea. Unloaded it decades ago. 73