HP 5342A Microwave Counter, Max Freq Limit

[joeqsmith]

If you have one of these counters and an RF generator, I am interested in knowing what is the upper frequency is.

I built up a comb generator with an amplifier and filter to but was not able to get it above 21GHz.  It's a pretty weak signal.   

I have an old military document that shows 26.5GHz for the 5343A with the APC-3.5 input only.     The databook I have seems to show the same thing, 18GHz max for the 5342A w/ N and 26GHz for the 5343A.   

If the 5342A can read up to 26GHz, with unspecified performance, if you have a way to measure the sensitivity, could you please provide this. 

Thanks.

[0culus]

So for the 5350B all you need to do to make the base counter think it has the 26.5GHz option is to move some jumpers. You won't get optimum performance due to lack of a 3.5mm connector, but it will still count higher than 20GHz. Wonder if the 5342 is the same way.

[hendorog]

If you have one of these counters and an RF generator, I am interested in knowing what is the upper frequency is.

I built up a comb generator with an amplifier and filter to but was not able to get it above 21GHz.  It's a pretty weak signal.   

I have an old military document that shows 26.5GHz for the 5343A with the APC-3.5 input only.     The databook I have seems to show the same thing, 18GHz max for the 5342A w/ N and 26GHz for the 5343A.   

If the 5342A can read up to 26GHz, with unspecified performance, if you have a way to measure the sensitivity, could you please provide this. 

Thanks.

I've got a 5343 with a stuffed uWave front end so I've spent a bit of time poking in mine. You may already know more but just in case:

I think the sampler is the main (and possibly the only) internal difference between the 42 and the 43 (ignoring the connector). The 43 was featured in the HP catalogue when it was released and it goes into some detail about this part. I'll try and find the reference.

The uWave parts are entirely contained in two small boxes behind the connector, one being the sampler and the other a pre-amp + SRD sampler driver (from memory). I wouldn't be surprised if the rest of the unit is the same or at least very similar.

Building a new front end would be cool and surely possible with modern parts.

Edit: Here is the HP catalog: https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1980-04.pdf

[joeqsmith]

Thanks for the link.  It's interesting how they mention extending the frequency range but don't state what it was. 

A new microwave frequency counter, Model 5343A, makes its own contribution by extending the frequency range to 26.5 GHz and improving sensitivity and dynamic range by about 1 0 dB across the band. Furthermore, features have been added, making the instrument more system- oriented.

If you look at the service manual for the 5343A, Fig 8-9 Block Diagram, they show it at 18GHz.  However, the detailed block diagram shows it at 26.5GHz.

It's possible that they continued to produce the 5342A long after the 5343A was released and then updated the older counter to use common parts (including firmware).   Later serial number may read up higher.   Hard to say. 

[hendorog]

Thanks for the link.  It's interesting how they mention extending the frequency range but don't state what it was. 

A new microwave frequency counter, Model 5343A, makes its own contribution by extending the frequency range to 26.5 GHz and improving sensitivity and dynamic range by about 1 0 dB across the band. Furthermore, features have been added, making the instrument more system- oriented.

If you look at the service manual for the 5343A, Fig 8-9 Block Diagram, they show it at 18GHz.  However, the detailed block diagram shows it at 26.5GHz.

It's possible that they continued to produce the 5342A long after the 5343A was released and then updated the older counter to use common parts (including firmware).   Later serial number may read up higher.   Hard to say.

Here is the journal containing the 5342A - which is more detailed than the 5343A one.
I noticed the 42 supports amplitude measurement but the 43 doesn't. I guess due to the added IF buffer amp in the sampler circuit.

https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1978-05.pdf

I think you are right in that both were sold at the same time as they are both on this datasheet:
http://www.testequipmenthq.com/datasheets/Agilent-5343A-Datasheet.pdf

That datasheet also says the 42A can go to 24GHz with option 005. So you might be onto something

Edit: Further to that, the option 005 is not compatible with option 006 - which I think is just a coax limiter attached between the port and the sampler. So possibly option 005 may be a replacement sampler unit, or an amp...

Edit Edit: Google to the rescue yet again - option 005 install guide:
https://xdevs.com/doc/HP_Agilent_Keysight/05342-90057.pdf

[joeqsmith]

Thank you for taking the time to hunt these old papers down. 

Mine has no options installed.   It has a connector on the back for the DAC but it's just a plug for the hole (see attached).   You can see it also has the 5088 7022 sampler.  So it wasn't upgraded and left unmarked.   I suspect they just have some amount of head room on the 18GHz spec and never published it and the firmware has no way to detect the options and it happy to display what ever. 

This counter appears to still be all original.  It was one of the few things I ever bought off eBay where it actually did work and not by the modern eBay definition of the word.

Ebay definitions:

Referbished: wiped it off with a rag
Tested: plugged it in
Working: no smoke came out when we tested it

[hendorog]

Nice one. Great score getting it in working condition, working replacement samplers are rare as I have discovered.

In your case as you already have the correct sampler for 005, it would seem you can transform it into a 24GHz counter by just replacing the A12 IF board with the listed one - at least based on what it seems to say in the upgrade.

[Tony_G]

Wait, isn't the 7052 sampler the 24GHz one?

I had one that worked up to near 21GHz and only had the Option 001 timebase and 002 amplitude measurement so I think there is a fair amount of headroom in the standard sampler.



TonyG

[hendorog]

Wait, isn't the 7052 sampler the 24GHz one?

I had one that worked up to near 21GHz and only had the Option 001 timebase and 002 amplitude measurement so I think there is a fair amount of headroom in the standard sampler.

Yep you are right, sorry guys I read that too quickly.

[joeqsmith]

...
I had one that worked up to near 21GHz and only had the Option 001 timebase and 002 amplitude measurement so I think there is a fair amount of headroom in the standard sampler.

Do you still have the counter and a way to test it?

[Tony_G]

I bought a 5343A so I gave the 5342A to my Dad back home in Australia - I can ask him to check something if you need it but I'm not sure he has a signal source working (his 83592A is a bit broken right now) that goes up that high.

How can we help?

BTW Here is the 5343A video:



TonyG

[LazyJack]

If you need the DAC option, someone just posted a post on how to retrofit this to an existing 5342A.

https://diysquared.blogspot.com/2020/07/adding-opt-001-and-opt-004-to-5342a.html

Looks like it is quite simple to do it, if you can source the parts, which should not be hard, even for the DAC.