[time-nuts] More Z3801/Tbolt comparisons
GandalfG8 at aol.com
GandalfG8 at aol.com
Fri Sep 4 16:48:45 UTC 2009
In a message dated 04/09/2009 16:32:09 GMT Daylight Time,
phill.r1 at btinternet.com writes:
I must say that much of what you have stated is right, I have a 53131A
counter and the basic time-base is a joke, but agreed, we mostly use a
common external reference with our instruments.
There are some exceptions, as I am finding with a very recently purchased
HP 8657A Sig. Gen. that has the option 001 oven oscillator. This is a 1998
production (made in the US), the TCXO would seem to be a very stable
with coarse and fine adjustment - after running for 48 hours its holding
Mhz to ^10. In fact it would seem to be somewhat better than the TCXO in
Marconi 2024 Sig. Gen. - - hence my singing the praises of HP.
I suspect the 8657A option 001 is likely to be a 10811B, which also
appears in quite a lot of other HP kit and is also the better of the options for
the 53131A and 53132A.
They are certainly very nice oscillators.
The large number of Racal 199# on the UK market in recent times are I
suggest, ex UK military issue and as portable instruments have probably
a rough life, and have frequently been stored for ten years in somewhat
environments. I would suggest that buying equipment that has come from a
commercial origin, and has been part of a rack test set-up, have been
cared for and sometimes have had very little use. What do you others think
about this theory ?
You're quite right that the majority of 199x counters available in recent
times are ex-mil but that doesn't always mean a hard life, although I agree
there can be an element of risk involved when buying them.
My first 1991, bought a few years ago, was ex-mil but had never been issued
and was still new in its original box, having been taken out just once
since original calibration to check it was still "serviceable".
The one just bought is also ex-mil, this one has been used but looks to
have been very well treated.
It carries a label indicating the warranty ran out in 2001, so I assume it
was manufactured in 2000, with last calibration expiring in April 2009.
Although it's fitted with the manual pouch for portable use it doesn't show
any signs that it's actually been used portable, the case and front and
rear panels are unmarked, so I suspect it may have just seen bench use.
There's no obvious problems with the front panel switches either, which is
another good sign, although, of course, that could change tomorrow:-)
It's very likely that there's a lot more of all sorts of test gear, on
Ebay at least, that's ex-mil rather than ex-commercial so it's really quite
difficult to avoid unless prepared to always buy from dealers who are able to
guarantee previous ownership, and also prepared to pay their much higher
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