[time-nuts] HP5370A vs B version
Glen Hoag
hoag at hiwaay.net
Sat Jul 20 19:18:24 UTC 2019
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, Taka Kamiya via time-nuts <time-nuts at lists.febo.com> wrote:
>
> 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 are right - especially for an instrument like this, standard is extremely important.
>
> ---------------------------------------
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Saturday, July 20, 2019, 11:02:19 AM EDT, Bob kb8tq <kb8tq at n1k.org> wrote:
>
> 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 external standard, it really does not matter a lot which OCXO
> is in it.
>
> Bob
>
>> On Jul 20, 2019, at 4:21 AM, Frank Stellmach <frank.stellmach at freenet.de> wrote:
>>
>> 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 board, has the OCXO (10811-60111), which is a must for absolute T.I. and frequency measurements.
>>
>> Maybe the firmware was also improved a bit, I think mainly concerning the GPIB steering of the trigger circuit.
>>
>> This T.I. counter is supposed to be superior over others of that era, because this special time interpolator was more linear.
>>
>> I really love mine, so I don't want to sell it.
>>
>> Frank
>>
>>
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>
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