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Tuesday, 15 January 2019

New version of the SMA Simple Spectrum Software available and some bad news related with Google Maps!


After quite some time, I once again updated the SMA Simple Spectrum Analyser software.

No big changes, only minor bug fixes and some GUI enhancements.

But unfortunately I did notice that Google changed their Google Maps API to v3 and is discontinuing V2. This has some consequences for my software, see yourself:

The problem is that you need to have an "API key" with Google, to enable embedded Google Maps:

Basically, it is no longer free to use Google Maps in your own applications. This means that the "Log on Maps" funtionality of my software (affects all three versions: SMA/NWT, SSA3000X and CMU200/CRTU) will eventually be disabled or I may find a way that allows the user to put in his own Google Maps key.


Monday, 11 June 2018

Remote control of the R&S CMU200 and CRTU - some notes...


I get frequently asked questions about how to remote control the R&S CMU200 and CRTU. Some want to program their own application, some just have issues getting my software to run.

So here are a few hints, tips and tricks!

SCPI - What is it?

Again, from Wikipedia:

"The Standard Commands for Programmable Instruments (SCPI; often pronounced "skippy") defines a standard for syntax and commands to use in controlling programmable test and measurement devices, such as automatic test equipment and electronic test equipment."

SCPI is a syntax that describes a set of commands and parameters to remote control a test equipment. Because SCPI is a standard, all devices using it can be controlled by a generic software - the VISA architecture. Each device has its own SCPI command set, but the structure and syntax is common.

Since the goal is to do complex measurements, VISA offers not just a tool to send SCPI commands  and receive the respective answers - it offers programming possibilities and a programming interface, so that one can develop independent software that interfaces to the devices.

GPIB - What is it?

Wikipedia explains:

"IEEE 488 is a short-range digital communications 8-bit parallel multi-master interface bus specification. IEEE 488 was created as HP-IB (Hewlett-Packard Interface Bus) and is commonly called GPIB (General Purpose Interface Bus). It has been the subject of several standards."

GPIB is the interface through which you connect the test equipment with the computer.

VISA - What is it?

From Wikipedia:

"Virtual instrument software architecture, commonly known as VISA, is a widely used I/O API in the test and measurement (T&M) industry for communicating with instruments from a computer. VISA is an industry standard implemented by several T&M companies, such as, Anritsu, Bustec, Keysight Technologies, Kikusui, National Instruments, Rohde & Schwarz, and Tektronix."

VISA is the software implementation that allows to comunicate with the test equipment, which normally use SCPI commands.
Schematic of GPIB - SCPI - VISA

Keysight Connection Expert 2018

The Keysight Connection Expert 2018 is part of free Keysight Instrument Control Bundle or IO Libraries Bundle, made by Keysight (former Agilent, former HP).

It is one of many VISA implementations.

You can download the Keysight Instrument Control Bunde here:

Important: The recommended version to run my "VMA Simple SPectrum Analyser" software is to b downloaded here:

Select versin 2017-11-15 2018 Update 0.1 - Build 18.1.22713.0

This is the version I am using and it definitely works!

Please bear in mind that Keysight is not the only vendor offereing a VISA suite. There are other VISA suits! Your lb computer can have such a different VISA software installed and/or a different Keysight version. As a result, my software may not run correctly or at all!

Don't change your VISA installation and configuration, if you require it for production work, as I am not able to give any support on VISA - please use a different computer, if you want to try my software and the currently installed VISA suite does not work.

Running my software is safe, though, as it does not change any settings.

Connecting through RS-232

One way to use my software is to connect the CMU200 or CRTU through a null-modem cable to the PC. This is certainly the easiest and cheapest way.

Some notes, though:
  1. You need to select the serial communication protocol and choise are NONE, XON/XOFF or CTS/RTS. If you are using a full featured null modem cable, then you can select the CTS/RTS mode, which uses handshaking through dedicated lines. If you are using just a simple cable (2-3, 3-2 and 7-7), you can try XON/XOFF or NONE.
  2. The best way to connect the device to the PC is to use a regular COM-port on your motherboard. This will fully support the RS-232 communication. The problem is that modern computers normally don't have this port anymore!
    The work-around consists in using a USB to RS.232 adapter. These can be purchased cheaply, but beware: not all work correctly!
    Problems can be expected with adapters using the Prolific chip, as this is normally a fake chip and the official driver will not work! You need to use an old Prolific driver (pre 2010), but those won't implement XON/XOFF or CTS/RTS handshake properly, so you need to use NONE. Even so, some users experience problems with Time Out on the VISA protocol. This is not a problem of my software!
    I had good results with adapters based on the CH340 chip. These can be bought for the ridiculous price of 1€ (including free shipping):
  3. Serial Communication is about 10 times slower than using a GPIB adapter! This means that the spectrum refresh rate will be slow. It works, but it is no real fun.

Connecting through a GPIB interface

This is the way to go, but beware that the only tested and supported GPIB interface (by my software) is the Agilent 82357B GPIB USB interface.

The good news is that you can buy one cheaply at eBay:

Notice that you want to buy the "B" model and not the "A" model.

There seems to be something fishy about these offers at eBay, as the price of this interface is really low (should be around 10 times more expensive) and the sellers mention "refurbished" along with "new".

The fact is that these devices (at least mine) come in a sealed Agilent box with certificate, but they do seem to be refurbished. You need to look with great attention to notice some minor marks.

I think these are surplus devices that got repackaged, probably in fake boxes (look genuine, though).

Anyway, they do work and the price is great.

Configuring the connection

You need to setup the CMU200 or CRTU for the remote settings:

You need to configure the Primary Address (0) and the Secondary Address (1). This is required no matter if you are using GPIB, Com1 or both.

Here are some additional settings I use.

If you use serial communication, don't forget to setup the RS-232 settings:

The CMU200/CRTU has two serial ports, I only use Com1. Pay attention that you connect the cable to the correct connector...

Now you need to configure the Keysight Connection Expert settings:

For GPIB connection:

 For RS-232 Connection:

Detailed RS-232 settings, matching the settings on the CMU200/CRTU:

Want to program your own application?

Keysight provides some great help, including VB .Net examples.

Take a look here:

Hope this helps!


Sunday, 20 May 2018

VMA Simple Spectrum Analyser for Siglent SSA3000X - Download Page

VMA Simple Spectrum Analyser for
Rohde&Schwarz CRTU and CMU200 - Download Page

Change Log:

2018-04-06: Added DEBUG button in SETUP tab to help
            solving connection problems
2018-03-25: First Tracking Generator implementation
            Further VISA handling improvements
2018-03-24: Spectrum reads CRTU settings upon start
            RF Input port selectable
            Several bug fixes and optimisations
2018-03-11: VISA settings are now stored in Registry
2018-02-26: Adapted GUI to R&S CRTU
2018-02-25: First release


- different visualization modes (LIVE, MIN, MAX, AVG traces; "Fade" mode, 3D spectogram)
- transponder recognition
- satellite recognition by transponder pattern matching
- record & playback of spectrum
- bandwidth measurement (-3dB, -6dB and -60db)
- MIN, MAX, AVG db values
- two marker with indication of delta frequency and delta db
- 9 configurable frequency presets
- GPS functionality, including Google Maps measurement plotting
- MATH operations
- SWR measurement
- Trace export to CSV
- ...


This software requires Keysight Connection Expert 2018, which can be downloaded for free here:


The software *should* work fine without any installation: just unpack and start executable.

You need to setup the VISA connection in Keysight Connection Expert 2018:

For this to work, you need to configure the Remote settings of your CRTU/CMU200:

SCPI Connection:
Port = GPIB, Com1, Com2 or GPIB + Com1
Primary Address [GPIB]
Primary Address = 0 (or whatever you want)
Secondary Address [GPIB]
Address1 = RF Mode = Non-Signalling

For RS232 connection go to Comm. tab and configure as follows:
Application = Remote
Baudrate = 115200 (requires FW 4.x or higher)
Data Bits = 8
Stop Bits = 1
Parity = none
Protocol = CtsRts

It is recommended to use a USB-GPIB interface:

Saturday, 5 May 2018

Disclaimer and User Privacy Information

VMA's Satellite Blog is a hobby project


Vitor Martins Augusto
Rua do Revilão, 383
4100-426 Porto

You can contact me through direct e-mail: vma AT norcam DOT pt

I have no commercial purpose with this blog.

Privacy Policy

I take your privacy seriously and do not keep any personal data.

However, because this blog is hosted at (Blogspot), please consider the privacy notice of this service provider:

In order to fully comply with all regulations I have opted to remove AdSense. This means that this blog does NOT contain any advertising and does not trace any user data for the purpose of AdSense (according to my knowledge).

I do not share personal information with third-parties nor do I store information about your visit to this blog.

Please consult the privacy policy of Google and Blogger, regarding the analysis of content performance through the use of cookies, which you can turn off at anytime by modifying your internet browser's settings.

I am not responsible for the republishing of the content found on this blog on other web sites or media without my permission. This privacy policy is subject to change without notice.

VMA Simple Spectrum Analyser Software

Through this blog you can download three versions of my "VMA Simple Spectrum Analyser" software, which comes in specific versions for:

  • SMA/NWT devices
  • Siglent SSA3000X
  • Rohde&Schwarz CMU200/CRTU
To use the software, you are required to send me an email containing your SYSTEM CODE. I will reply with the matching ACTIVATION CODE, that enables the software.

By requesting the ACTIVATION CODE and sending me the SYSTEM CODE, you are providing me with the following information with your explict consent:
  • Your e-mail address
  • Your SYSTEM CODE, which is based on the MAC ADDRESS you selected
Again, I will not provide this information to any third party and I will not use this information for any other use than replying with your ACTIVATION CODE and answering to questions, feature requests or bugs.

You can request this data to be deleted at any time - just send me a message and I will delete all e-mails I received from you or sent to you.

Use of Mediafire for download

This blog offers download for the "VMA Spectrum Analyser Software" - a hobby project of mine.

The files are hosted at Mediafire. Please review their policies, prior to downloading any file offered at this blog:

If you do not agree with these policies, do not download any file from my blog.

I do not track any information from Mediafire - I don't even have access to the number of downloads made for each file made available in this blog.

Use of Paypal for donation

If you decide to do a donation, I will send out a permanent ACTIVATION CODE.

Please bear in mind, that I am not responsible for Paypal's privacy policy:

Please consult it prior to using the Paypal service to do a donation. If you don't agree with Paypal's privacy policy, please refrain from doing a donation!

My software can be used without any donation, it just requires periodic ACTIVATION CODE requests, at no charge.

Donations are used to help funding the purchase of required hardware and accessories that allow me to further develop and improve the VMA Simple Spectrum Analyser software. This is not a business, it is a non-profitable hobby, the amount of donations I have received per year are far below any taxable amount.

Please feel free to contact me in case there is any doubt.


Monday, 30 April 2018

VMA Simple Spectrum Analyser - Put these harmonics into propper use!

It is no secret: when using the SMA/NWT device to generate a test signal, there will be a lot of harmonics, due to the absence of any filters. Of course, this is acceptable, considering the price of these devices.

This is what the spectrum looks like, when generating a test signal at 1GHz:

The picture was taken with help of my HackRF One, which allows to render a spectrum up to 6GHz.

One can clearly see:

  • Fundamental: 1GHz
  • 2nd Harmonic: 2GHz
  • 3rd Harmonic: 3GHz
  • 4th Harmonic: 4GHz
  • 5th Harmonic: 5GHz
So, what happens when the Fundamental is set to 4GHz, which is close to the maxium supported frequency of the ADF4350/ADF4351? You should have harmonics at 8GHz, 12GHz, 16GHz, 20GHz!

A quick test using an LNB connected to my Promax HD Ranger 50 SE showed that the harmonics can be used at much higher frequencies than the ones specified for the SMA/NWT devices!

Of course, to use the VMA Simple Spectrum Analyser to generate specific harmonic frequencies is a bit cumbersome, as you need to calculate the corresponding fundamental frequency - even if the math is just dividing by the order of the harmonics, it is a pain.

So I added some new functionality to my software:

The new Harmonics Signal Source allows to easily select the desired frequency, no matter if Fundamental or Harmonics. The graphics show were the harmonics will be located in the frequency space and with the scrollbar, the frequency can be set dynamically - if the generator is turned on, the signal will follow the scrollbar!

Of course I added a Harmonics selector to the Sweep Generator, too.

Need an application example? Here you go: use this in combination with the MAX HOLD function of your satellite field meter and you will be able to fully test your LNB's!

In this example I am trying out the Inverto White Ka LNB, which does 19.7GHz-20.2GHz. Unfortunately, the Promax HD Ranger 50 SE does not support negative LOF and this would be useful for this LNB, as it has a LO of 21.20GHz.

Notice how I just place the SMA/NWT in front of the LNB!

Activating the MAX HOLD and using the Sweep Generator, one can test the whole supported frequency band of the LNB. As expected, the SMA/NWT does not produce a really flat signal over the extended frequency range, but it is still OK to do GO/NO GO tests for LNB's and to figure out if there is something really wrong.

Head on to the download page and discover signal generation up to 22GHz with the SMA/NWT devices!

Do you have a different application for the "Harmonics Signal Generation" with the VMA Simple Spectrum Analyser software? Let me know about it!


Sunday, 25 March 2018

VMA Simple Spectrum Analyzer for CRTU: Tracking Generator function is now supported!


One of the drawbacks of the CMU200/CRTU is the lack of a Tracking Generator. This is a useful functionality to measure filters, for example.

Well, I implemented a "software" driven Tracking Gerator:

You can download the new version here:


Saturday, 24 March 2018

VMA Simple Spectrum Analyser for CRTU: new version!


Here is a quick note to let you know that I just uploaded a new version of the VMA Simple Spectrum Analyser for CRTU (works with CMU200, also).

Besides some bug fixes and many optimizations, I added these new functions:

  1. When the Spectrum is started, it will read the current settings of the CRTU/CMU200. This way my software doesn't change any settings.
  2. You can now select the desired RF input port from my software.
  3. The GPIB address is now stored in the Registry.


  • My software uses a DLL of the Keysight Connction Expert 2018! This is the reason my software won't connect to any other VISA version.
  • You can download Keysight Connection Expert 2018 for free
  • It should run in parallel with other VISA installations (no guarantee, though... if you break your existing installation, you are on your own).