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A number of TAIT T801 frequency
standards have just appeared on the UK surplus market.
They're ex-cellphone bases and I understand have
been ditched in favour of GPS-locked standards.
Consist of an Rb standard driving a couple of 12.6
MHz synthesizers that can be digitally offset by a few
Hz.
The interesting bit is the Rb standard which
is a Frequency Electronics Inc. model
5660A.
Its output is 10 MHz and on
switch-on it ramps up and down over a few kHz searching for Rb lock.
You can see it on
a frequency counter. If it's working then after
about 3-4 mins it stops quite suddenly and the "Lock" light
comes on, if not it goes on searching forever and
the lock light stays off. Unfortunately the
ramping is a built-in
software function and (unless somebody knows
better) can't be switched off so if no lock not
useful as an ordinary 10 MHz. osc. When locked, can be set precisely on frequency with a small
trimmer.
Anybody know anything about
these units? FEI website not very
helpful.
Have checked four and three were dead. The
good one had a 2000 datestamp, the
others 1996-1998 so might be a clue there.
I sent an email to FEI asking how long they were
good
for but no answer.
Walter G3JKV.
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