[time-nuts] Has anybody checked this? GPSDO in kit

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Sat Oct 22 17:55:21 EDT 2016

On 22 October 2016 at 17:22, Chris Albertson <albertson.chris at gmail.com>

> You have to remember what this thing replaces.   In ham radio, some people
> are using vacuum tube oscillators with mechanical variable capacitor
> tuning.  Maybe some advanced rigs use gear drive on the capacitor shaft to
> allow more exact tuning  This Si chip is considerably better then 1940's
> technology.

Well, as someone else pointed out, hams are not using this sort of thing
now - or at least not in any significant numbers.

I recently bought a "new" 2 m transceiver - which is actually a 40 year old
Yaesu FT-225RD. When fitted with a Mutek front end (GW4DGU), they were
arguably the best 2 m transceiver ever made.

Mine drifts quite a bit, and I need to look into why. It can be two things

* Crystal - 100 and odd MHz
* VFO  - around 8 MHz

I heard of someone replacing the VFO with a cheap Chinese DDS as an
"upgrade". Actually, I suspect it was probably a downgrade, as I would
expect the VFO to be a lot cleaner.

I've not taken it apart to fix mine, but from what I have read, it would
appear the crystal is the main source of drift, and not the VFO. A
frequency counter will soon determine if that's the case in mine.


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