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Rohde & Schwarz CMU200

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ZL1CVD:
Just upgraded an 8924C for a CMU-200. It has a fault - internal RF loop path 1 test fails. Does anyone have any ideas where I should start? Also does anyone happen to have service manual with circuits - the one i have is missing all module exploded diagrams and circuits. Next step for me it to install a SSD. Cheers.

Nuno_pt:
Not very easy to find that detail manuals in the R&S stuff.

Try run RF Self Test < http://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_news_from_rs/167/167_CMU200selftest.pdf >

I'm also looking to buy one of this because of the Spectrum Analyzer and Tracking Generator till 2.7GHz, and also for the Audio Part, so I can measure the RX sensitivity of the radios with Power at 10dB Sinad.

 

ZL1CVD:
I have been playing with it for a few hours now. I ran most of those tests and all reported fine except the RF loop back.

There is no tracking generator that I can find. Also no RF demodulation which is a big shame. So for general ham radio use, you have spectrum analyzer, RF generator & audio generator/analyzer.

Spectrum analyzer is very nice and allot faster than the older HP's I'm used to (8924 & E8285). But these older HPs still offer allot that this doesn't. Well, that I haven't found yet....

Nuno_pt:
The RF Generator or Signal Generator from what I see can be use to be feed in the unit, to measure one filter, and don't know if it will track?
But for some prices of this units, an SA, Signal Generator, and Audio generator and analyzer, it's ok.

Some findings, from what the CMU have:

" The CMU200 is great bench-top unit. The RF gen covers 100kHz - 2.7GHz (0.1Hz steps, -130dBm to -27dBm up to 2.2GHz, -130dBm to -33dBm between 2.2Ghz and 2.7GHz), the power meter covers the same range in wideband mode and 10Mhz to 2.7GHz in selective mode, and measures depending on the input and type of signal from -80dBm to +53dBm (calibrated, not unleveled). The SA goes from 10Mhz to 2.7GHz, the span from zero to full (which many vector SAs in such testers can't do), RBW is from 10hz to 1MHz in 1/2/3/5 steps. My unit is the newer model with USB instead of PS2 ports for a keyboard and has the optional 2nd RF generator (same range as the first one) and the optional audio generator/analyzer (20Hz to 20KHz) which is nice. It's fast and has a clear and intuitive UI.  "

ZL1CVD:
Yes it has all that but I can't see how to make the gen track. And yes, have to agree, for the price I paid, I did get a good deal.

From what I have read, some are saying the CMU200 PSU are starting to fail also.

The CMU screens have RF shielded glass in front of the TFT - mine has deteriorated badly - a green oxidization from edge working its way in. Replacement from R&S will be mega $$. I've just pulled it out and will get the local glass shop to cut a bit the same size. I'm not worried about emissions and this environment isn't going to create anything that will effect the measurements I make with it. 

For all its greatness, I can still pick up and E8285A or 8924 for around same price and they do allot more - but allot slower and will need almost all electro caps in PSU & display changed. The CMU could easily do the same as the hardware is more than capable. I wonder if its possible to hack its software to add features....

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