[time-nuts] HP 5345A

[John Miles]

There is probably nothing wrong with it.  Two things to check: first, the
lock range is super-narrow.  Make sure that the 10811s are very close to
each other using the manual trimmer(s).  For the same reason, both OCXOs
will need to warm up for a few minutes.

Second, the 5345A needs an unusually-strong signal at the external reference
jack, about +6 dBm or better if you're driving it from a 50-ohm source.  The
input load is actually in the 1K neighborhood, not 50 ohms.

I've added a MAV-11 MMIC at the external-input jack on the A8 assembly on
both of the 5345As I've owned.  None of my gear has had problems running
from a CATV splitter on the Thunderbolt, except the 5345A.

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of bg at lysator.liu.se
> Sent: Friday, December 29, 2006 3:41 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] HP 5345A
>
>
> On Fri, December 29, 2006 19:01, Colin Bradley said:
> > I just picked up a 5345A from eBay. This unit has a 10811 oscillator
> > instead of the 10544 depicted in the manuals I have. The serial
> number has
> > been removed. Does anyone know if there is an EFC adjustment for this
> > counter or is the course control the only way of setting frequency?
> > Colin
>
> I have another problem with my 5345A. It works fine using the internal
> oscillator, but when feeding an external oscillator (in this case an 10811
> from another counter) it refuses to do anything.
>
> Is this a common problem, or is there som kind of magic involved that
> needs care in the phaselocking of the internal oscillator?
>
>