[ARC5] Amazon Sig Gen as Crystal Subber

[Tim]

Hi Dave - good stuff.  Thanks..
I have used my DDS generator to drive the T-784/GRC-109 transmitter.
Externally ground the xtal socket pin connected to the feedback cap (the
upper female) and feed the lower pin via a .05 uf blocking cap to the
oscillator grid/47K resistor.  1 volt sine wave drives mine to full output
on 3550 kc for example.  Hardly "Mil" but it can provide some flexibility
absent a crystal on the desired freq... Very handy...you just have to deal
with the "backwave" when receiving...
(I had previously done this with an LM-14 freq meter and 600 mv to the
crystal socket as above.  Works great)

73, Tim
N6CC

On Mon, Apr 6, 2020 at 8:40 AM David Stinson <arc5 at ix.netcom.com> wrote:

> If you use one of these nifty DDS sig gens from Amazon to sub for a
> crystal, I've found you need capacitor coupling to keep DC off the output
> of your DDS.  Must use CMOS, Square or Pulse wave to drive the tube
> oscillator.  Sine Wave won't do it.   Best amplitude is 9-10V peek, but a
> 5V square wave will drive it at slightly reduced performance.
>
> 73 Dave S.
>
>
>
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