[Lowfer] GPS frequency lock (and ZL1BPU DDS exciter)

[Lyle Koehler]

I looked at the index of the Digi-Key catalog, and found that they have
TCXOs in stock for several frequencies, including 10.0 and 12.8 MHz (part
numbers X493CT and X489CT). The price is about $15, which makes them an
attractive alternative to a high-quality crystal with a PTC thermistor.
These units are also voltage-controlled, which means that they can be used
in a GPS-disciplined circuit. Only problem is that they are surface mount,
although with only 4 pins on a DIP-8 sized package, I can probably cope with
the soldering...

I'm getting ready to order the parts for the ZL1BPU DDS exciter, and am
willing to order extra sets of the major parts (microprocessor, TDA7052A,
CD4060, 78L05, precision resistors and TCXO) for other US LowFERs who are
interested in the project. Maybe that way we can share the darned
shipping/handling charges. I could probably break even at something under
$30 (postpaid) for the above-mentioned parts. Exact cost will depend on the
quantity -- some of the parts will have a price break for quantities of 10
or more -- but I *definitely* don't want to get into the parts business and
would want to limit the offer to the first 10 people who respond. The ZL1BPU
exciter is pretty simple, but it is *not* a beginner-level project, and no
PC boards are available. However, I am willing to load the firmware into the
AVR microprocessor, which means you don't have to buy it from Murray (he
says that's OK). You will still need a serial PC interface and software to
run the exciter, but that software is free. Details of the exciter are at
http://www.qsl.net/zl1bpu/micro/EXCITER/Index.htm   Anyone interested?

Lyle, K0LR

Lyle, K0LR