List your test equipment "scores" here!

[NiaDebesis]

Yesterday has arrived my krohn hite 3343A sold "as is" but it works just fine, scored for 38.50 bucks, am so happy

[cncjerry]

A new friend sent me an email stating he had 5 of the EGG TS-RFS Rubidium Frequency Standards he no longer wanted, one working and 4 that didn't lock.  I included a picture I borrowed from the web as I didn't have one handy.

On power up, all of them locked and the one that worked continued to stay locked whereas the others dropped.  I found a note that someone had replaced 5 of the electrolytics in theirs and I did the same to all of mine with great results.  They now all lock in less than 5 minutes and using the synthesizer switches I was able to set the frequency within 5E-11 on all of them.  This comes out to 10,000,000.0005 or less. 

The frequency settings are a little off, I wish I could get them a little closer, but these are clearly for timing only as the spurs are only about 70db down at best.  The can be cleaned up some by running them through some TTL logic as the close-in phase noise doesn't look that bad but the spurs at 2.1k and higher are the issue.

I am thinking of opening one up and taking the signal prior to their synthesizer if possible and running it into a DDS as this could drop the spurs to below 80db down.

Anyway, these are a steal at the price you see and they are very, very easy to fix.  They get hot, probably should have an external heatsink as I've measured them above 50C.

I've been into time and frequency-nuttery lately and have a Cesium beam coming between the holidays.  I received another note from the all-time Rubidium guru who has two Cesium Beam HP 5061B units he is letting go for a song.  So I will be fully configured by the time the next FMT comes around.  I need a better counter as I only have a 5335 and a 5371a TIA.  I read with jealousy the PM 6081 found a few pages back.

Anyway, if you are into Rubidium, take Mark up on his X72 boards as I have a set coming, Mark is just a ton of help (KE5FX takes the cake on support) and then look for the EGG TS-RFS and for less than $10 in parts you have a very nice standard.  The TS-RFS units I have all have greater than 10V of lamp light and a very large physics package so they will run a long, long time.  The run at 12W so they are power hungry, but my GPSDO units run at more than double that so I am going to keep the rubidium running and just use the DSO to check them.

One other note for those still reading, don't use switching supplies on any of these as I found out.  I found my problem that I had posted in the other forum as my 5V supply was noisy as hell.

Jerry

PS if the owner of the picture prefers, I'll remove it and replace with mine.

[Ice-Tea]

26 (Twenty-Six) Rohde & Schwarz CMU 200

So, eh, if you ever think you might need one: send me a PM 

Also a HP 35670A Dynamic Signal Analyzer.

[bitseeker]

26! Now, if I was in your neighborhood...

[nctnico]

26 (Twenty-Six) Rohde & Schwarz CMU 200

I hope you got them very cheap because the market is pretty much saturated.

[Ice-Tea]

As always: depends on what you call cheap, but: yes.

Not sure I understand why they are so cheap, though. Obviously, the cell phone communication test suites are not in high demand as they don't support the latest protocols but these units tend to be loaded with a GP power meter, SA and RF gen. That alone should fetch a pretty penny from a reputed brand like R&S.

I have one right now at home. Think I'm gonna do a quick review and drum up some interest 

[Berni]

Well i always stayed away from them due to these things often being so specialized. Some even require a licence key to make it work outside the specific radio bands or even to let you use it like a SA. Even then the SA is usually limited to narrow spans etc.

[nctnico]

As always: depends on what you call cheap, but: yes.

Not sure I understand why they are so cheap, though. Obviously, the cell phone communication test suites are not in high demand as they don't support the latest protocols but these units tend to be loaded with a GP power meter, SA and RF gen. That alone should fetch a pretty penny from a reputed brand like R&S.

The problem is that they are signal analysers and not spectrum analysers. Their minimum RBW is 10Hz, can only show one line (which sucks because many times you need to have more lines on a spectrum analyser to compare measurements), the noise level isn't that great and they 'only' go to 2.7GHz. The same goes for the audio analyser (if fitted/enabled): it is made for telecom use and not hifi.  Add the boat anchor factor to that too.

[Ice-Tea]

The problem is that they are signal analysers and not spectrum analysers.

I don't see how that is a disadvantage?

Their minimum RBW is 10Hz

Or do you mean it's a disadvantage because, as a result, the RBW is relatively poor? And is it? 10Hz is not that bad?

can only show one line

You lost me... can you explain? Would like to understand/learn...

The same goes for the audio analyser (if fitted/enabled): it is made for telecom use and not hifi.

No argument here.

Add the boat anchor factor to that too.

Don't agree. It's a decent SA and RF gen, all rolled into a high quality build instrument. The UI stinks, though...
[/quote]

[Berni]

I would have thought that being a signal analyzer would give it a very sharp RBW. I got a old HP vector signal analyzer that goes from DC to 10MHz and it has its RBW go down to 30 mHz (not Mega)

I would like to see a review of one of these CMU 200 tho.

[nctnico]

The problem is that they are signal analysers and not spectrum analysers.

I don't see how that is a disadvantage?

Their minimum RBW is 10Hz

Or do you mean it's a disadvantage because, as a result, the RBW is relatively poor? And is it? 10Hz is not that bad?

can only show one line

You lost me... can you explain? Would like to understand/learn...

Normal spectrum analysers can show 2 or more lines and you can also apply math to them. This allows to make one baseline measurement in one trace and then subtract the actual measurement using the second trace. Or just display the baseline measurement and the new measurement at the same time. That is pretty handy when fixing an EMC problems. You can have the result for the unmodified circuit on screen and see exactly how much progress you made (or not) with fixing the problem.

10Hz minimum RBW isn't bad but 1Hz RBW seems to be standard on the cheap Chinese spectrum analysers so you have to compete with that. Also the sweep time of the CMU200 is slow (>100ms) in comparison.

[Ice-Tea]

Ah, ok. That makes sense. I mostly had/worked with old SA's (8560E and others) where comparing and math isn't an option anyways

[Berni]

Well a lot of spectrum analyzers don't go down to 1Hz RBW. Like for example the popular Rigol DSA8xx only goes down to 10Hz RBW. Not that its that big of a deal really since they slow down to a snails crawl across the screen when you use resolutions close to that fine. Tho funny thing is that for modern SAs it has become common to specify the noise floor at 1Hz RBW, when it can't actualy go down to 1Hz they extrapolate it down to 1 using math.

Math is a fair point there. Being able to have at least two traces and do things like subtract them is really useful when comparing things or when using it with a tracking gen where you want to zero out your generator and cables. Some of that can be fixed trough software tho. I use a Rigol DSA832 at work for EMI and its annoying to set up every time as not all of the setup can be saved to file and recalled. So i instead created a tool in excel using VBA (Yeah i know... horrible) that talks to it over LAN and sets it up for all the tests and pulls the traces off it in to a nice big graph that is then used in the test report. But yeah when fault finding its useful to have multiple traces right there on the screen of the instrument.

Doesn't the 8560E have multiple traces and math? I have a old boatanchor HP 8566B that has it. Well okay it has only 2 traces and can only add and substract but what more do you need really.

[Ice-Tea]

I thought it didn't. Guess I'll fire her up again tonight

[peertux]

Just bought a Systron Donner PS50-1 power supply on eBay. If anyone has any info like accuracy or a schematic that would be great because I can't find anything about it anywhere

[Vgkid]

Your silver unit looks way better than my yellow/beige unit. I do have a manual for it , somewhere. No scanner , but I can take some pics of that when I find it.

[beanflying]

So I was looking and talking to a US seller on evilbay about buying a tidy Agilent 34970a DAQ and a single card for about $800 AUpesos. Some !@#$ brought it out from under me while I slept. 

Time to trawl evilbay again for weeks I thought but 5 of them turned up 2 hours drive from me for $400 AUpesos with a choice of two cards fitted.

So being a responsible and budget minded person I brought two of them 

The seller made me do it by offering 3 gpib cables "free' with the second one

[PTR_1275]

Good deal on the 34970

I got mine a few years back, was $150 buy it now plus $30 shipping. Bloke was in Brisbane and had make a offer enabled. I thought about making an offer but would have been kicking myself for years to come if I missed it, so I paid the $180 and got it a week later. Was a few months out of cal, but didn’t care.

I’ve been looking for more ever since and recently at work we are looking to improve our testing setup, so they are looking for one. I saw the ones you bought but being pickup only makes it a bit difficult from the other side of the country.

[Ice-Tea]

Whoops. Missed 3 CMU200's, which makes 29 in total. 2 CRTU-RU's as well.

[nctnico]

Whoops. Missed 3 CMU200's, which makes 29 in total. 2 CRTU-RU's as well.

Stack 'm up like a wall and turn them on! It would make for a cool picture. That also gives you the chance to check each unit for the installed options. For your sake I hope they all have the same hardware/software options so you don't have to describe every single one of them.

[Ice-Tea]

For your sake I hope they all have the same hardware/software

That would be nice. But no. 

As for the wall: yeah, would look like a million bucks. New, they would be a million bucks.

[Mr. Scram]

26 (Twenty-Six) Rohde & Schwarz CMU 200

So, eh, if you ever think you might need one: send me a PM 

Also a HP 35670A Dynamic Signal Analyzer.

I wouldn't even know what to use one for.

Do I see a spectrum analyser in there?

[Ice-Tea]

What do you mean? Most of them have an SA and RF gen integrated.

Or do you mean the 8560E I have for sale?

[Mr. Scram]

What do you mean? Most of them have an SA and RF gen integrated.

Or do you mean the 8560E I have for sale?

I meant that I don't even know what this device is intended to achieve. The world of electronics is full of tools I didn't even know existed. Quite regularly that's followed by absolutely not being able to do without one any longer

Just out of curiosity, what's a ballpark figure for one of those?

[peertux]

Your silver unit looks way better than my yellow/beige unit. I do have a manual for it , somewhere. No scanner , but I can take some pics of that when I find it.

That would be great. Thanks!