I was the R&D project manager for the 5334B in a former life.  It was a
low cost counter designed to win the low bid on big military contracts.
I had to throw it together in less than 1 year from start to ship.
It is FAR from the best counter HP made, although not the worst either.
It is also now 35 years old.  Since you have only a couple hundred
dollars to spend, maybe the '34 or '35 are the best you can do.
Don't bother with the optional C channel.  Its only interface is HP-IB
by the way, like anything of that era.

Rick
N6RK

On 3/13/2023 11:26 AM, John Miller via time-nuts wrote:

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

The prescaler in the HP5386 is far and way HP's best prescaler.  The
prescaler chip was made by HP at their Santa Rosa fab, was always BIG
bucks as a component.  I'm sure it hasn't been made for decades.  I
believe the chip is mounted on a hybrid "gold brick".  Nothing you
could repair yourself even if you had a replacement chip.  Sorry for
the bad news.  I know all about the chip and the 5386 itself.  Knew
the designer very well, etc.  He used to give me a hard time about
how much better it was than the one I designed into the 5334B,
and he was exactly right.  In my defense, my prescaler chip cost
only $2.00 :-)

Rick N6RK

On 3/13/2023 1:47 PM, Roy C Long via time-nuts wrote:

On 3/13/2023 2:24 PM, Bob Camp via time-nuts wrote:

SRS was a formidable competitor to HP/A/K due to its
unique business model.  I would seriously consider
anything they make.

Rick
N6RK

Hi Bob,
Lots of interesting info here, for sure. To start, I'll clarify and answer the first four questions:

• How good is good? I don't really know - a lot of this depends on how much I have to spend. I got my Ramsey CT-125 for $30, and it's great, but can't perform any analysis. How about "trustworthy measurements in the range of 1-5ns".

• Budget? I'd like to stay under $250, unless an incredible option comes along for not much more. I'm basing that on two things: 1) what I have seen 5334s and 5335s sell for, and 2) how much I can usually reasonably allocate to hobbies.

• How soon do I want it? I've been getting progressively deeper into "TimeNuttery" over the past 3-4 years, so I'm fine waiting 6-12mo for the right piece of gear to come along - I just want to know what to look for.

• How much effort? I'm willing to put in a lot of effort as long as there is a light at the end of the tunnel. I have plenty of experience replacing mundane components in older gear (RTC batteries, tag tantalum caps, carbon resistors, etc.) so minor work doesn't scare me off. However, the $150 5386A that "just" needs a prescaler? Yeah, I know how that goes - it sits in a closet for two years and I end up buying another functioning 5386A for $350.

I am very interested in home brew projects, especially if it's something I can build myself. I am aware of the TAPR TICC, and similar time interval counter projects, but I'm also interested in a "general purpose" counter that can be used to, say, characterize an oscillator in another piece of equipment.

If I could find a 5334 for $50, I'd probably jump on it right away. Looking at recently sold on ebay currently places working 5334Bs closer to the $150 mark, and 5335As around the $250 mark. Prices on old gear have started to climb again.

John

Hi

So here’s another “twist or two” to the decision process:

Back in the day, you had fancy counters and more generic stuff. The 5345/5360/5370 all are in
the fancy category. The SRS 620 also very much goes into this bucket.

The fancy stuff inevitably has better specs than the more generic gear. It also has a design that
(likely) uses crazier parts. What was crazy back then may or may not be crazy today. One guess
is that “crazy stuff” likely needs more attention to keep it working than the more generic designs.

The advantage of going to the fancy stuff of generation zero is that it’s performance (still) is pretty
good. Price wise …. who knows?. The fancy stuff is more rare. That makes pegging a price or
getting one in the next couple months (at a given price) a bit more questionable. You might get
one dirt cheap, if you shop for …. years?

The more generic gear is all over the place. It’s not as high spec, but there are dozens of them
up for sale every day. Finding a second (or third) one as a “parts donor” is not all that crazy an
idea. Buying a 53181 for next to nothing to give you a supply for your 53132 … yup, that works.

All of this still is based on a “I want to measure 10 MHz” sort of baseline. If 22.48 GHz is the typical
target, that’s a whole different ballpark. Multiple channels (to measure delta’s on 1 pps signals )
also change the target a bit.

The next branch to this thing is the timebase. In a lot of labs, the counter had a TCXO (or XO) in
it. It never / ever ran on that timebase. It always was locked to “something else”. In the modern
day, that might well be a GPSDO. Indeed this does have an impact on your counter purchase.

We’re also still on the “stock lab test gear” trail. There are advantages to a professionally bundled
up device. There also are things you can do with various bits and pieces. TAPR is not at all a
bad place to look for some of those pieces …..

Bob

Hi

The biggest issue seems to be the price debate.

Some things drop as they “age” and then head back up as “rare” cuts in.

5334 counters have indeed headed below $50. That was when 5313x
counters went for > $400. These days, 5313x’s seem to be the better bet
in terms of bang for the buck. Working 5334/5’s are getting “rare”.

Bob

If you are looking for a 5335a in "certified" condition, I would
recommend Joe Cline KN5U.

joecline5747@comcast.net

I've got a 5335a and a 3325b from him over the years.  Think I also
bought a HP electronic load as well.

What's unique about Joe's offering is that he performs a HPIB driven
certification & alignment which is documented.  In my case I wanted a
unit that was 100% functional, in good cosmetic condition, and was
properly aligned as it would provide core functionality for the test
bench here.  If you contact Joe, you should ask for his PDF showing the
test racks.  If you like old school gear, it's worth asking for just to
have a look at a very unique and professional setup.

I've got no relationship with Joe other than being a very satisfied
customer.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

On 3/13/2023 5:23 PM, Richard (Rick) Karlquist via time-nuts wrote: