[time-nuts] Favorite counters (current production)?

Magnus Danielson magnus at rubidium.dyndns.org
Sat Nov 11 06:34:24 EST 2017


On 11/11/2017 11:42 AM, Tom Van Baak wrote:
>> Rank your preferences!
> I echo Magnus. In almost every photo of national timing labs you will see SR620's in use. The interface, specs, readability, and reliability are really good. Also SRS seems to support their products forever. For the curious, the full BOM and schematics are in the service manual. Note they just added the FS740 (GPSDO) but there's no update for the 620 after all these years. The downside is that they are larger, heavier, and louder than many modern instruments.

Yeah. There is also some limitations in them, but if you follow the 
instructions in the manual and maintain it properly, you have one nice 
instrument. I have two, and I would rule out getting more.

I should do fan-replacement on one of mine. Not all things is as good as 
they should be, but it remains one of my favorites and it keeps doing 
duty in major NMI labs, because it remains good enough and it is understood.

> For high-performance and high-throughput the CNT-91 is my choice. Quiet, feather-light, and it's a continuous dual-edge timestamping counter with raw data output capability.

It remains one of the nicer counters to use. The CNT-91 is a CNT-90 with 
performance enhancements. Mine is a CNT-90.5 or so.

CNT-90/91 remains produced just as the SR-620. Some of the original 
folks still maintain it. It would be nice with a follow-up.

> That said, when I need a quick or long-term measurement I almost always grab a HP 53132A and run it in talk-only mode, collecting data with RS232->USB. Once you get used to the 5 key (arrows & enter) UI you're all set.

I use that one too, but it is not my favorite. The 53131A/132A 
unfortunatly lost some of the directness and ease of us, what is today 
called UX, user experience, of the previous counters. The 5335A remains 
one of the best as it comes to intuitive user interfaces IMHO, also for 
some of the measurement it remains relevant and useful. The 5370A/B has 
it's issues, but is relatively straightforward too.

> About the 53230 -- When it came out I got a pair on loan from Agilent; one with and one without OCXO. When I saw how badly they handled the external REF-in and how noisy the REF-out was, I figured it was a green team that designed it and I'd give them another product life cycle to learn about precision timing. So there are no 53230A in my lab. As soon as they come out with a redesigned B version where the ext/int REF are good to 1 ps (like you'd expect with a 12 digit/s counter), I will be the first to buy one.

Also, as being reported by the friends at Norwegian NMI, there is 
something funky about. They got to borrow one from Ole Petter Rønningen.
It was there in the York EFTF 2016 poster session, and I even made a few 
folks aware of it as "interesting". If I had more time, it would be 
interesting to dig deeper into that issue.

A trouble with some of these modern counters is that sometimes their 
processing isn't as transparent as it used to be. The trouble with that 
is that we need to know deeply what goes on in the processing and we 
even end up revese-engineer the processing when the counters "improved" 
processing gives us funky measures. I have myself being researching what 
such processing _should_ be doing. Only a small handful of vendors have 
been attempting to look at it.

Some of its features is really nice, but so far one haven't made it onto 
my bench and there is some funkyness going on that doesn't make it very 
attractive to spend money on right now. A customer uses them to send 
measurements over the network so they can log things. Got a bunch when 
they where on sale.

That said, I hope Keysight can straight it out. I'm not out to bash 
them, but I'm not as excited about their products as I was back in the 
HP and early Agilent days.


> /tvb
> ----- Original Message -----
> From: "Magnus Danielson" <magnus at rubidium.dyndns.org>
> To: <time-nuts at febo.com>
> Cc: <magnus at rubidium.se>
> Sent: Friday, November 10, 2017 11:50 AM
> Subject: Re: [time-nuts] Favorite counters (current production)?
> Hi,
> I would say CNT-99/91 and SR-620.
> Bob has a point about 53230, since the others is older, but on the other
> hand, it is a bit of a gamble. There are many aspects that goes into the
> longlivety of a product, such as access to components, but also strategy
> of companies.
> The CNT-90/91 an 53230 both have graphical presentation, which is very
> beneficial. The SR-620 still have better performance even being older
> than everything else.
> Cheers,
> Magnus
> On 11/10/2017 05:37 PM, Bob Camp wrote:
>> Hi
>> There is no perfect answer. I’d go with the 53230 simply because it *might* be supported
>> the longest.
>> Bob
>>> On Nov 10, 2017, at 11:17 AM, Scott Newell <newell+timenuts at n5tnl.com> wrote:
>>> What current production freq counters do people like for general time-nuttery these days? There's a chance I can get a decent counter for work, so I'm looking for suggestions. Bonus points for fanless. Don't need anything past 200 MHz or so. Prefer ethernet over USB or GPIB.
>>> The SR620 looks to be pretty big and a little dated. The 53230A seems to have better specs and screen than the Tek/Fluke FCA3k series. Am I missing any?
>>> Rank your preferences!
>>> -- 
>>> newell  N5TNL
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