[TenTec] DDS PTO replacement for old Ten Tec rigs

[Barry N1EU]

I strongly suggest that you give some attention to how "clean" the DDS
output was before yanking the PTO.  By "clean" I mean the presence of spurs
and birdies on the rx/tx signal.

73, Barry N1EU

On Thu, Oct 26, 2017 at 12:47 AM, Curt Benjamin via TenTec <
tentec at contesting.com> wrote:

> Guys, since the N4YG DDS is no longer available and too expensive anyway,
> I have been exploring the idea of making my own. So far, I've taken the
> Arduino code to control one of those $8 AD9850 DDS modules from China to
> tune from 5 to 5.5MHz but I haven't found a way to add an RIT line to it.
> What I'm thinking might work is making something like a 2MHz xtal
> oscillator with a voltage-controlled shift line using a varactor and mixing
> that with the Arduino/AD9850 DDS that tunes from 3 to 3.5 MHz instead.
> I don't think any of these frequencies would pose any problems in either
> the DC receiver in the C21/22 or in any of the superhets of the other
> various models but I'm not sure. What do you folks think? Is that a good
> scheme or should I change the frequencies. I picked 2MHz because it's
> available in a off-the-shelf crystal. Thanks.
> Curt, K8AI
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