[time-nuts] Re: Frequency counter recommendation wanted

[Bob Camp]

Hi

This pretty quickly gets into “how good is good?”, “what’s the budget?”,  “how quick do you need it?”, 
and “how much effort do you want to sink into this?”.

If you have the time to shop, eBay can and does turn up some “finds”. When those pop up, they
likely will not hang around all that long. The more common listings at 3 or 10X the magic price will
indeed keep hanging around for a long time. 

Indeed HP / Agilent / Keysight isn’t the only game in town. The SRS 620 is still a pretty good beast. 
There are various “home brew” projects out there that compete quite well with a number of the counters
mentioned above. 

So, what happens as you move along?

The 5334 / 5335 generation machines came in at a nanosecond or two sort of resolution. Their competitors
might have pushed a couple more ns into that budget in the same era. Typically they are big boxes with
GPIB interfaces. The 5345 / 5360 / 5370 go back to the same time frame, but generally give you more resolution. 
Still the same big box / GPIB setup.

How well is something this old likely to work? Those displays are pretty old and getting harder to find. There
are some unique front end stuff in them that can be tough to repair ( put 5V into the 5335 and there goes the
front end on 1X attenuation / DC coupling ….). 

Next up are the 5313x machines. They get you a serial output that should work for logging. They also are a 
bit smaller. Power supplies typically are their weak point.  Resolution is in the 100 to 400 ps range depending
on model and how picky you are.

While it seems crazy, the 5323x generation has been out long enough to be bouncing around eBay. You add
an ethernet interface to the mix. Resolution goes down into the 10’s of ps. Don’t count on using the ref out
for anything ….

Price?

The 5334 should be a sub $50 item by now and the 5335 still under $100. The 5313x generation should come
in below $300. The 5323x generation should be below $1500. Yes, you can easily find all of these for 5X 
those prices.

All that and we haven’t even begun to talk about frequency range, or what you want to use it for.

Bob


> On Mar 13, 2023, at 2:26 PM, John Miller via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hey All,
> Long ago I reached the point where I really need to get my hands on a real frequency counter, but I was able to work around with with cobbled-together solutions. Now I have started a new project and I need something trustworthy that I can rely on for good measurements. I'm looking for something "general purpose" that can also do time interval measurements as well as logging, be it to GPIB, serial, USB, whatever. The ability to operate off of an external timebase would be nice, too, since I do have a known-good rubidium oscillator. 
> 
> The HP 5334B and 5335A are good options, but I have some anxiety about buying older equipment from ebay that may be in rough shape or questionable provenance. That said, I suspect that there are other reputable options out there, and I want to keep my mind open. I'm not biased towards old or new or any particular brand, but I would like to keep the cost under a couple hundred dollars. 
> 
> Anyways, I figured if anyone could get me some recommendations, it would be you guys! (And of course if anyone here has one they want to sell, let me know!)
> 
> Thanks in advance,
> John M.
> KC1QLN
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