[time-nuts] Frequency Counter Choice

Thu Oct 22 15:29:11 UTC 2020

Mark,

Yes, the VFD on those counters do seem to have a limited lifetime. I 
have some 20 years old that are getting hard to read in bright light.

If the VFD dies, yes, the counter will continue to measure just fine, 
not only all the serial talk-only data output, but the full capability 
of SCPI over GPIB. TimeLab won't know the difference. The downside is 
that the custom little annunciation icons inside the VFD won't be 
visible and those are sometimes quite useful, for example, to know the 
status of "ext ref", or even the M/Hz/u/s units.

Here are some other ideas:

1) Just replace the dead / dying VFD. You can find NOS on eBay. Taka has 
done this.

2) Use an Arduino or similar to capture the digital signals to the 
display board containing the failed VFD to create a mirror of the 
display. A multi-digit LCD module should work. Or try one of those nice 
looking programmable OLED pixel displays.

Or, for a bit of nostalgia, not to mention a top spot on Hackaday, use 
Nixie tubes for the readout and NE-2 bulbs for the status icons. Or get 
modern and output the display over BLE and write a phone app as the display.

3) Instead of replacing the front panel readout, instead do all your 
comms over SCPI, to the point where you have created a virtual 
instrument, not unlike some of the logic analyzer or 'scope PC apps. 
This solution would be very welcome by lots time-nuts. It means we could 
fully operate our 53131/53132 counters with the VFD disabled. The 
downsize is that it requires a GPIB (Prologix) adapter.

/tvb

On 10/22/2020 7:22 AM, Mark Spencer wrote:
> I am just curious how viable would it be to use a 531xx series counter with Timelab if the counter display has failed ?
>
> Thanks in advance
>
> Mark Spencer
> mark at alignedsolutions.com
> 604 762 4099
>
>> On Oct 22, 2020, at 6:36 AM, Bob kb8tq <kb8tq at n1k.org> wrote:
>>
>> Hi
>>
>>> On Oct 22, 2020, at 7:50 AM, Giorgio Barinetti <giorgio at barinetti.it> wrote:
>>>
>>> Hi,
>>>
>>> As a newbie in the field, I've collected, by chance, some frequency standards.
>>>
>>> Now is the time to measure them, and see how they perform.
>>>
>>> I've inherited a 5371, but something tells me that is not the right instrument - and maybe is even faulty.
>>>
>>> So, I'm in the need to buy a counter to use togheter with TimeLab.
>>>
>>> Choices are many, but I'll try to avoid the "older" machines lile 5370 or 5335. The 531xx series seems nice ( money apart )
>>> But again : which one between the 3 ? 53131, 53132 or 53181 ?
>> 53181 = single channel 400 ps counter
>> 53131 = dual channel 400 ps counter
>> 53132 = dual channel 100 ps counter
>>
>> 5370 (when working) = dual channel 20 ps counter
>>
>> The gotcha is that none of them are good enough to properly measure 1
>> second ADEV on a good ( but still could be cheap ) OCXO. A mixer based
>> setup is a cheap way to get things done, even with a 5335.
>>
>> The 531xx counters all share a couple of issues:
>>
>> 1) The power supply was made by who knows who and their quality is not
>> the best. Good news is that the power supply out of a (cheap) 53181 will
>> swap over to revive an expensive 53132.
>>
>> 2) They have a fan, it plugs with dust. When that happens it gets hot inside
>> the cabinet. Things (like the power supply) die as a result.
>>
>> 3) They have a VFD display. It’s a nice one, but they do wear out. Replacing
>> them is problematic.
>>
>> 4) They have a fancy setup to add digits to a frequency measurement. It
>> can lead you astray. It also tends to go deaf right at 10 MHz. There are app
>> notes out there that explain the details.
>>
>> 5) With *any* counter, a good external reference is the way to go for “Time Nut”
>> grade measurements.
>>
>> None of that is to say they are a bad counter, far from it. I have a number
>> of them and have been using them here and at work for decades. The 532xx
>> counters are the latest and greatest. They are on eBay, but not cheap.
>>
>> Bob
>>
>>
>>
>>> Can somebody shed some light, and maybe help even to found a baseline for us beginners ?
>>>
>>> Regards,
>>> IZ2JGB
>>> Giorgio
>>>
>>> My NTP servers: (ntpd on FreeBSD - PPS in via Serial)
>>>
>>> HP/Symmetricom 55300A  https://www.ntppool.org/scores/93.41.196.243
>>>
>>> Efratom Rb/Xc GPSDO https://www.ntppool.org/scores/95.255.136.126
>>>
>>>
>>>
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