[Milsurplus] Fwd: Crystal Substitute

[Ron De Silva]

---------- Forwarded message ---------
From: Ron De Silva <rdesilva49 at gmail.com>
Date: Sun, Jul 7, 2024, 11:30 PM
Subject: Re: [Milsurplus] Crystal Substitute
To: B. Smith <smithab11 at comcast.net>


I purchased one of the new Prog Rock 2 units in April.


I wanted to try out the unit on the latest MAB I restored.

I tried a few different designs.

The simplest approach works pretty well by winding a toroidal xfmr to take
the 3vpp output up to 16vpp in circuit ,still not as good as the original
30vpp in circuit drive to PA, but not much change in output level.

The toroidal xfmr driving the receive mixer was fine.

The prog rock has continuous output on 3 clocked outputs in each of 8 banks.

Obviously. The TX osc running continuously wipes out the receiver.

To handle switching.

I programmed BANK 0 with the first receive frequency in CLOCK 0 and no
transmit freq in  Clock 1

And programmed Bank 1 with the desired receive frequency in CLOCK 0 and the
TRANSMIT frequency Clock 1

When in transmit, I took the 1.5v on TX to turn on an opto isolator and its
output selects Bank1 on transmit.

I made some little pc boards to hold all components and the whole assembly
plugs into the side by side FT243 crystal sockets.

No mods were  done to the MAB except add two wires to pick up the minus
6volts power from the C battery and the +1 5v from the transmit tube
filaments .









On Sun, Jul 7, 2024, 12:15 PM B. Smith <smithab11 at comcast.net> wrote:

> QRP Labs is now taking preorders on their programmable crystal ProgRock2.
> No I have not tested the new board.
> K4CHE
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