Once upon a time, I looked into the front ends of the 5370 counters (mostly
5370A) and found that it was practical to build a replacement using modern
chips. I then lost interest in the project when I found an Ebay seller with
a lot of 10 pieces of the 5370A chip for dirt cheap (sorry, all
There was an informative thread back in 2005 on the topic of hp 5370A
vs. 5370B:
https://www.febo.com/pipermail/time-nuts/2005-April/018053.html
It's worth reading the entire thread, or at least, read the reply by JJ
(from Agilent T):
kb...@n1k.org said:
[Context is 10811s.]
> Because they are an un-sealed unit, power off storage is not kind to them.
> Some take a long time to recover. A few never really seem to settle down.
What's the mechanism? Lots of stuff ages faster when it is warm/hot. I'd
guess humidity.
What's
There were field upgrades from HP5370A to B, I believe offered through the HP
field services operation. I have an A->B converted unit. I believe it has the
original front end, but the “B” firmware. It has been a while since I opened it
up.
Sent from my iPhone
> On Jul 20, 2019, at 10:35,
Am 20.07.19 um 10:21 schrieb Frank Stellmach:
the B version has a 500MHz front end, copied from the HP5345A, with a
matched pair of amplifier / Schmitt trigger hybrids.
The A version has separate amplifier and Schmitt trigger ICs.
There were also changes on the trigger circuit.
Then the B
Hi
If you have a pile of 10811’s a fun experiment is to put them on power for a
couple months.
Log the frequency once a day or so and watch how they “drift in” to whatever
the final
frequency is. Because they are an un-sealed unit, power off storage is not kind
to them.
Some take a long time
Thank you.
I really do not want to buy from eBay. So far, none showed up with zero
problems. There's always something. My intent is to lock it to house
standard which is a GPSDO. I have lots of 10811 here but I don't know when
they were made. All I know is they are all 10811-6011. You
Hi
If you are buying them on eBay, it is not at all clear which OCXO your A or B
will show up
with. The 10811’s get swapped back and forth with earlier units in a lot of
used gear. One
might *think* it’s a one way exchange, but I’ve seen it go both ways.
If you lock the counter to an
Hi Mr. Taka Kamiya,
the B version has a 500MHz front end, copied from the HP5345A, with a
matched pair of amplifier / Schmitt trigger hybrids.
The A version has separate amplifier and Schmitt trigger ICs.
There were also changes on the trigger circuit.
Then the B version has a simplified µP
The "B" version uses custom hybrid modules for the inputs... and the CH1 and
CH2 hybrids are not the same... so you can't swap a CH1 hybrid with a CH2
hybrid.
I think the A and B model counters are fairly equivalent in their sensitivity
to input damage. It seems to be a lot harder to find
Hi
They both run hot and have “interesting” calibration procedures. Count on
spending some time running
through this and that to get the best performance out of them. The B does seem
to run a bit better, but
both meet the same basic specs.
The SR610 is a very similar device (with some similar
What are the differences between HP5370A and 5370B version?
I have been told A's input ports are rather delicate and it has been better
protected on B version. I found notes on A and B and looked a them side by
side but honestly, they are difficult to compare. Anyone on list who had both
and
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