[TenTec] DDS PTO replacement for old Ten Tec rigs

Katz Ajamas ajamas.rn at gmail.com
Thu Oct 26 15:47:20 EDT 2017

Aloha Curt!

Have you looked at the AQRP VFO?
Si570 based.

$45 or so (price is in pound sterling)
Si570 based.

The above two kits are quite similar.

I have the AQRP. Not using with a Tentec. It's my signal generator for the
shack :-)
I've just ordered a VNA kit from AQRP. It's VIA on the web site but they've
recently added I/O ports.

The only part of the AQRP kit I found challenging was soldering the Si570
chip. Missed a pad on the first go around. Rumor is that Kees is coming out
wit a smaller version of his VFO so you may want to ask before you order.
The display might be small enough to fit the window on the C21.

Then there is the qrp labs kit. It's only $33
Si5351a based.

You could really hotrod that C21. take a look at the manual for the QRP
labs QCX transceiver for some ideas.

73, -Bob ah7i/w4


Message: 4
Date: Thu, 26 Oct 2017 00:47:13 +0000 (UTC)
From: Curt Benjamin <k8aicurt at yahoo.com>
To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
Subject: [TenTec] DDS PTO replacement for old Ten Tec rigs
Message-ID: <158533031.4975337.1508978833829 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

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-sh

-do not look into LASER with remaining eye!

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