[time-nuts] Any simple way to get 200 MHz from 10 MHz?

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Mon Sep 29 04:17:21 EDT 2014

On 28 Sep 2014 13:19, "Jim Sanford" <wb4gcs at wb4gcs.org> wrote:
> Dave:
> Check out w1ghz.org.
> Paul has some designs (and boards) that can lock different oscillators to
a reference.  He uses a long time constant to manage phase noise.

I looked into that but it is an expensive way. PCBs are $6 each!!! I am
going to order 3, despite I am told what I want to do is impossible!  Paul
is clearly not aiming to get rich selling them.

> His objective is good enough performance to generate GPS stabilized LOs
suitable for weak signal narrow-band amateur radio communications.  I would
suspect that such would be more than sufficient for what you are trying to

Yes, I think so too.

> For that matter, in your application, multiplication of a really good
oscillator could probably be good enough, although pay attention to the
filtering to keep out harmonics you don't want. Given this, Paul's setup
may be simpler to execute.

Yes I think so too.

> Good luck, and please share what you decide.
> Jim
> wb4gcs at amsat.org

Well at $6 each for a PCB,. Paul's oscillator is hard to ignore.

I still have the problem I am told what I want to do is impossible!  But I
might spend the £500 or so for Keysight to provide me the cables and front
panel overlay needed to add option 012, which is direct access to the A and
B receivers.  I am pretty sure with direct access to the receivers,
something must be possible.

I have been thinking about adding that option for a while,  as it gives an
extra 16 dB of dynamic range for some measurements.  But then the
possibility of extending the frequency range down (or even up) adds to the
desire to have option 012.

There's VERY little difference between an HP 8720D with the latest CPU an
firmware,  compared to an 8720ES. In fact I bought a set of 8720ES manuals
as they are a more accurate description of the instrument than the 8720D

A dealer quoted me £15,000 for an 8720ES with this option and would give me
£7000 trade in on mine. Spending £500 on 5 cables and a front panel overly
is more attractive than spending £8000 on an upgrading the model.

You might wonder why don't I make the cables, but they are 2.4 mm to SMA. I
have no way to make them or test them.


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