Anritsu MS860xA (and likely MS268xA) options

[tmbinc]

OBLIGATORY WARNING: This may mess up your device. Don't do this.

It took me some time (even though in retrospect the mechanism is obvious...) - here's how you can make sure the enabled options of your Anritsu spectrum analyzer match the hardware, and enabled those that were accidentally disabled (like Ethernet). 

First, you need to enable "Maintenance Mode". This can be done by sending the following command via SCPI:

MAINTE SIGANA,ON

For example, you can configure the communication interface to serial, and then send "MAINTE SIGANA,ON\n" with a null-modem cable. GPIB and Ethernet (if enabled) should work as well, but I haven't tested. There -is- a way to enable maintenance mode via a different mechanism (likely pressing a magic key combination? or an internal button?), but I haven't been able to figure out how. After that, press "LOCAL" so you get back control.

After that, enter the configuration (press "Config"), and then press "System". Without maintenance mode enabled first, you'd now be able to chose the "system" (i.e. select the software module when you press "TX Tester"/"Signal Analyzer"), but with maintenance mode, you get into a more advanced "Configuration" menu.

Here you can change the product configuration (Type/Model/Serial/Frequency spec), as well as reset the mechanical switch counters, sub-board module numbers, but most importantly, you can edit the enabled options.

I was able to enable option 002 ("Narrow Resolution Bandwidth" aka. FFT mode), and 009 ("Ethernet"). I tried switching option 046 ("Auto Power Recovery", i.e. non-functioning standby mode - which is actually a feature as most of the MS860xA have been used in automated test setups), but unfortunately it seems to be a hardware option (so I observed no change).

Some options are set to not be disabled ("NOf", "NOn"). Interestingly not all options have an entry , but you can just add them.

On my device, I can use the power sensor in the TX Tester, but not the power meter in the Spectrum analyzer (shift-option -> Power Meter says "you need the power meter option"). I've tried adding Opt 21 ("power meter" for Spectrum Analyzer; from MS2683A datasheet), and while it made me able to start the Power Meter, it's non-functioning. It's probably a different hardware option than the TX tester power sensor, unfortunately, or the calibration is way off.

Make sure you capture your set of enabled options first! Not sure if it's possible to backup the internal state to a CF card first.

I've tested this on version 4.8, the only one I had available (which was also pre-installed on my device). If someone has another version (I know Wuerstchenhund had one showing 4.12 in startup, but not sure if that's newer or older) I'm curious.

Have fun!

[eevcandies]

Option 21: Power meter function
Frequency range 100 kHz to 32 GHz
Level range –10 to +20 dBm
Applicable power sensor MA4601A, MA4701A, MA4703A, MA4705A
Display
Selectable from W, dBm, and dB (RELATIVE), Digital

[fumitti]

i've confirmed that it works via ethernet as well.
if want to enter the maintenance mode with just a keystroke, hold down the 0 key until it starts.
and additional items will appear in the CAL menu during maintenance mode.

[tmbinc]

Oh, indeed! Holding "0" at startup - the device will beep before switching on the screen - will also enable maintenance mode! Curious - is this documented? Is there a service manual available?


I noticed that when I set my device (MS8609A, 13.2GHz model) to "20GHz", the UI lets me select a longer span, up to 30GHz (for some reason, not 20). Obviously band 3+ is not showing any data as my device is missing the hardware for it, _but_ Band 2+ (usually 7.8GHz to end of range for the 13.2 GHz model) still shows "something" until 15.2GHz (when it switches to Band 3+).

So I wonder if this could be used to extend the frequency range of the MS8609A to 15.2GHz? I don't have a signal generator for that range unfortunately (just a Leo Bodnar fast risetime pulse generator).

[tmbinc]

Oh well. Things are confusing, but in a good way.

I've looked at the MS8609A Operating Manual (kindly provided via https://www.eevblog.com/forum/buysellwanted/wtd-operating-manuals-1-3-for-anritsu-ms8608ams8609a-(paper-or-pdf)/), as well as the MS2681A/MS2683A/MS2687A/MS2687B operating manual (https://dl.cdn-anritsu.com/en-au/test-measurement/files/Manuals/Operation-Manual/MS2687B/Manual_MS2687B_v1_v480_E.pdf).

Both have block diagrams, probably the closest we can get to a real service manual; the MS8609A Manual unfortunately only for the MS8608A (the 7.8GHz version). As expected the MS2687x and the MS860xA only differ in details, particularly around the input side, where at least the MS8608A has the hi- and lo-power input via an attenuator and a DPDT switch (the MS8609A only has the low power input, so matches the MS2687x).

Now - what is the key difference that limits the MS8609A to 13.2 GHz, but the MS2687A to 30GHz?

The spectrum analyzer works by having a YTF as a pre-selector, and then mixes the signal down with a harmonic of the LO. It uses either the 1st (Band 1+, up to 7.9GHz), 2nd (Band 2+, up to 15.3 GHz) or 4th (Band 4+, up to 30 GHz) harmonic. There are no dedicated components for Band 4+ vs. Band 2+ - the YTF ensures there are no other components in the input left, and then mixes everything via the 1st LO and its harmonics.

So what is really missing for >13.2GHz operation? It's well possible the input blocks are not rated for >13.2GHz operation of course, or a different mixer is used.

But here is the thing: I've hacked my MS8609A - originally 13.2 GHz - to 30GHz (simply by setting the device bandwidth in the maintenance mode). As for a test source, I've used an https://www.innosent.de/en/radarsensoren/ipm-series-innosent/ipm-165/, a very low cost K-band radar sensor that is spec'ed at 24 GHz (https://www.innosent.de/fileadmin/media/dokumente/DATASHEETS_2016/Datenblatt_IPM-165_V8.5.pdf), and indeed, I can clearly see the signal around 24 GHz!

I double-checked that it's not a mirror of a lower frequency, but it seems to be the real deal.

[tmbinc]

Here's a screenshot of testing frequency stability of a cheap K-band radar at 24 GHz, on my MS8609A "13.2 GHz" transmitter tester.

Spoiler: The frequency not very stable. I've ruled out the analyzer just being unstable by setting up a second transmitter, but that frequency stays stable.

I've also used the IF output on the analyzer to capture the data with my Oscilloscope for better wideband FFT analysis.

[eevcandies]

That's a pretty cool find...Too bad it is hard to get a sig source to test

[NyquistNoise]

Hi all,

Thought I'd make an account just to give you all the information I've found on these units.
I decided to crack mine open and see what makes it tick, and can also provide clarity on the standby button option.
The insides of these analysers are fantastic, the build quality is some of the best around.
Re-enabling the standby option is quite easy on these units, near the front of the analyser is a 3 pin jumper. Simply move it from OPT to STD, this will re-enable the standby button. The option doesn't need to change in the menu, this is only an indicator (just like the rack mount option)
I've also attached an image of the jumper - I have some internal photos attached too so we can all drool at the RF goodness! 
My model (MS8608) doesn't go beyond 8GHz no matter what you change its upper frequency limit to, I expect the hardware is limited in the 8GHz variant - I seem to remember the YTF is only good for 8GHz.
In the photo showing the bottom of the analyser you'll see the power sensor, which is obviously required for the power sensing options.
I managed to get Anritsu to send me across some of the manuals, so if anyone needs any feel free to PM me. It would nice to try and find a way to enable some of the other software on these units - I'll take a look into doing this in time and will try and keep this thread up to date.

[jmurray]

Recently fired up our MS2683 at work and was hoping to enable the ethernet option.
I can get it into maintenance mode, but it doesn't appear to provide any additional options or capabilities within the Config menu. It does offer plenty of additional options in the Calibration menu though.

Does it need the original CF card installed for the Config options to be available?
I'm not sure if we ever had the card!