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It looks like my drawing will work. I used a 2N2222 to switch it. This is done on a perf board only. The amp keying is 25 volts @ 60 mA so I'll have to determine the 2N2222 base resistor. I'm

Ron, Thank you. I'm trying to learn these optocouplers so I need to figure out on my own. Attached is my drawing. After looking around I may order a few 4N25's. Bob

Years ago Gary made a relay-driven protector when it was seen that a large RF signal could damage the circuitry of the transceiver's RX2 port. It turned out to be an excellent RF amplifier keying

Another simple almost complete interface costing a few $$:? An Arduino 12V relay module.? It has an optoisolator input driving a reed relay.? 12V power, and a couple cables are all that's needed to

Hi all, Since I'm now retired I have time to goof off. I was trying to design an amplifier keying interface using an optocoupler. I don't need one since I already built a few using BJT's and/or

The Art Work for the PCBs is the property G3SEK. The circuitry is nothing special and is Public Domain. Using any one of the popular PCB Design CAD Programs (Altium Designer/Circuit Studio/Maker),

Hullo Tracey and the Group, Does anyone chat about with Ian, GM3SEK? He's a member of the Oxford University Radio club, and still active on VHF, I believe. Perhaps he might "Pass along the ball"

RE: GM3SEK Tetrode Controller Somewhere in the collection of 50 some years of building amplifiers there exists a new, pristine collection of Tetrode Controller stuff. There are two boards,

Is there a reason why we couldn't do a run of these, if G3SEK doesn't want to produce them (looking at the website, looks like it was last updated in 2020)? I have one of these I purchased a very

I have a complete, unbuilt WD7S Triode Kit, which I'm never going to use. See https://silo.tips/download/the-wd7s-triode-control-board I would entertain the thought of selling it if it is of

With ZERO bias, and using the SSB position,? you will end up with .220 x 2600 vdc = 572 watts, which will make both tubes go cherry red. JI's method uses a small lab typ supply, like my 0-30 vdc @ 3

Thanks for the link. I was thinking more than what it sold for.

Yes, but board was in Portugal. https://www.ebay.co.uk/itm/116441758244?_skw=116441758244

Still can't find it? Is this a European Ebay?

This listing sold on Thu, 9 Jan at 4:18 PM GMT ...

Must be on the European Ebay? Does not show up on mine.

These are now as rare as hen's teeth, so I thought that I'd flag it to the list in case anybody is interested. I have no connection with the seller. See eBay Item No. 116441758244 73s Tracey G5VU

The old man who sold it to me is reliable. The PA has hardly worked but it has not been turned on for about ten years. I will at least regenerate, a little, the filter capacitors, one by one, with

I'm not very familiar with the L7 Francois but if I guess you could do two tubes at once. Even if you just turn on the amplifier and key it, at full plate volts, if you think the tubes are OK. Run it

See https://www.w8ji.com/gettering_tubes_al572b_al80b.htm Thanks for this very interesting post. It should definitely be adapted to a 3-500ZG (graphite anode) because the photograph shows a 3-500Z