HP53370A or 5370B???

[RikV]

I want to buy a 5370A. Or should I wait until a 5370B comes By? What is the difference between the two? I A eventually upgradable to B? Or would a 5335A be a better choice? (I don't actually need 200MHz)

[KE5FX]

You're better off with the B model because it has fewer cheap IC sockets to cause flaky behavior.  Other than that, not much difference.

[Dr. Frank]

The 5370B has the very good OCXO 10811 built-in, which is mandatory for stable and precise measurements.
You might upgrade the A version accordingly.

The B version has an upgraded / compacted (1 instead of 2 PCBs) µP PCB, and better Firmware. Please check both Service Manuals for comparison.

The 5370A/B is a specialized instrument for best doing T.I. measurements, 20ps single shot. Max. frequency is 100MHz, which can be resolved to 12 digits @ 10sec Gate Time (external gating).

I prefer my 5335A over my 5370B, as it's got so many more versatile measurement modes, T.I. down to 1..2ns, which is sufficient for most oscillator stability measurements. It also has 200MHz and 1.2GHz frequency inputs, which can be resolved to 10 digits @ 10 .. 12 sec Gate Time, which can be achieved by changing an internal capacitor, or by using GPIB.
It should also have the 10811 OCXO.

John Miles (KE5FX) TimeLab program supports both counters, which is a big Plus.

It really depends on your use case, which counter to chose.

Frank

PS: If you go for the 5335A, make sure it has the OCXO, the digitally controllable front end, and the C channel.  Please check, which option numbers these are

[RikV]

Well, Dr.Frank,
I will try to go for both! But the budget is limited and being based in Germany, you also know the choise on ebay and the likes is limited. Buying overseas is nearly impossible due to customs, import duties...
Or: do other European citicens on this Forum have trics to import TE from the US Canada or even the UK? Please share!

[Dr. Frank]

Hi Rik,
you're fully right, good choice.
I bought my 5335A from U.S., many years ago, it was relatively expensive, due to shipping costs, but much cheaper than buying here in EU.
My 5370B was from German supplier Rosenkranz in Darmstadt, also many years ago, and its price was quite ok, but much more expensive than in U.S., where the time-nuts ruled. 
Frank

[cncjerry]

https://tapr.org/product/tapr-ticc/

I use that more than any of my other equipment for time interval work.  Many of the 5370s need work.  The 10811s are often pulled out of parts units and in my testing, the 10811 really depends on the unit.   If you use a GPSDO driving a wenzel 501 series, I think you would have a factor better performance than the 10811s typically found, and I have about 10 of them.  Though it doesn't matter for TI work, the wenzel oscillators have better than 25dB phase noise performance (again depending on the unit) than the 10811s.

The TICC above is supported by John's code.  It doesn't have the 20ps single shot performance, so if that's what is needed, then I guess the 5370 is your best bet.  Stay away from the 5371 as I have a pair of them and they sound like jet engines.  Nice units with tons of automated features.

Jerry

[Gerhard_dk4xp]

I have a 5370A and it is unusable because of way too many maybe-contacts.
But I did inherit it quite cheaply and it was the donor of a 10811 oven.
I solved my problem by buying a Stanford SR-620, different price league,
but still in cal (at that time). No regrets.

cheers, Gerhard

[RikV]

Well, auctions seldom work out the way one wishes. MISSED both!