WA1FFL DDS digital VFO keying interface module Ham tube transmitter isolation protection device
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- Опубліковано 15 кві 2024
- DDS Modified Johnson VF-122 VFO. Great VFO module. To safely operate with a tube transmitter, you need to ensure that key line voltages are isolated from the sensitive processor pin (23, Key). This pin has a 5vdc pullup. Grounding it keys the VFO. If you connect a transmitters key line direct the higher voltage can destroy the DDS chip! The D-lab Opto-key module solves this issue. I have been informed that most operators, free run the VFO, shift the VFO frequency while in receive so not to interfere with the receiver. Some have tried using relays for keying, but that introduces clicks on CW mode. So I set out to design a fast response keying & isolation circuit. Works great. Hook-up is simple. Small easy to interface. Other designs are in the works. Example Heathkit (DX-60) plus other popular models. If your interested, let me know. Right now only the Johnson Viking II model is tested, ready.
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I've been watching your channel for years. Great info, well done. I love the old Johnson transmitters and guitar amps.
Looks like a nice way to modernize the VFO! Great job!
WA1FFL lives only a couple of miles from my QTH . . . I used to talk with him a few times when I was working as a Gov't contractor at Newport Navy Base . . .
I know you have a large fan base with various likes and dislikes/not interested
But it doesn't stop you from your passion
Hello, Yes Sir, I know this is out of my typical, but it was fun to design & test. Appreciate it!
OK! I don't know what you said, but it sounded intelligent and now I want one if it will help my Nokia 2760 / N139DL work better. I find it amazing that NOS tubes we couldn't sell for $1.00 each in 1982 are selling for $30.00 or more now. Our boss gave us 30 days to sell what we could then they went into the dumpster. Minimum wage peasants like me couldn't get a small biz loan then to buy them all up and open my own repair shop.
Terry I like have that done with my 122 vfo for my Viking 2 how much it cost to have that done.w8dmx Kevin