PTT and TX/RX timing circuit progress!

[KJ4OLL]

Hi,
Working on the "final" circuits for the homebrew!
Amp is a simple design, one tube only, (3CX3000A7), driven by a 32V-2.
Receiver is an R-390.

- PTT using a relay sequencing-timing circuit from Don K4KYV.

https://www.youtube.com/watch?v=ueeq4h888tc


- Vacuum relay to switch antenna between TX/RX

Discovered that the lugs on the vacuum relay are made of something that I can't solder.
Considered using the TIG machine, but...

Anyway, resorted to the lathe and a microscopic tap & Bristol screws/wrench to fabricate the connectors.





Next will be the relay & related parts to provide the PA cutoff circuit as part of the PTT operation.
73
Frank
KJ4OLL

[w1vtp]

Outstanding!  Nice work.  Keep the posts & pics coming. Don has a good sequencing circuit for sure

Al

[KJ4OLL]

In the interest of others learning from my mistakes w/ the Kilovac-Gigavac H8 vacuum relay!

Too much force on the lugs is "bad".



Fixed:




Will try again with substantially more flexible conductors.
Frank
KJ4OLL

[w1vtp]

That's sad.      Yes, zero bending moment at all times is absolutely important on these and expensive transmitting tubes

Al

[KJ4OLL]

Hi,
Today's progress on the PTT and PA cutoff bias relays & circuits!



Mounted one of the spare Kilovac H8 vacuum antenna relays so as to not break another one....he said optimistically



Tomorrow some actual power up testing, and possibly installation in the amp...very exciting.....

73
Frank
KJ4OLL