Are more of these becoming available ? A lot have been bought up by
microwave operators recently.
The best way to use these it take out the oscillator module which runs
off 12 Volts and use that individually, then throw the rest away. A
bit wastefull perhaps, but the rest of the electronics is specific to
providing a source for a single UHF frequency and not very adaptable.
The Toyo oscillator itself is very good but does not have voltage
control of fine trimming. I published a modification to allow this in
a Microwave newsletter some years ago when these units first appeared.
Don't know the Racal unit, but believe it does already have varicap
fine tuning.
Andy G4JNT
----------
From: Alan Melia[SMTP:[email protected]]
Reply To: [email protected]
Sent: 2000-04-26 21:08
To: rsgb_lf_group
Subject: LF: High frequency-stability drive sources
Hi there has been some discussion about stable drive sources for
narrow band
modes. One possible source that sometimes becomes available these days
is a
Pye/Philips unit which used to be used as the frequency source for
quasi-synchronous radio communication systems, like the wide area
coverage
systems of the emergency and utility services. The unit model number
is
HS400 and it contains circuitry to lock a crystal to a 5MHz ovened
standard
oscillator (2 types with either a Toyo or a Racal unit). The stability
available is a few parts in 10^9. I think these units are now obsolete
so
may become more easily available. They are a little large being 19in
rack-mount units. If anyone does find one I have the technical
details.
73 de Alan G3NYK
[email protected]
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