A Small RF Power Meter with SCPI Connectivity


Need a small RF power meter with remote control capabilities ? Of course, you can buy this from the big names (Keysight, R&S, Anritsu, …). You get multi-sensor capabilities, wide dynamic ranges, a lot of measurement modes, fast reply, … but for a flexible solution about 10K€ are gone, and a simple commercial USB sensor is more than 3K€.

If you just need a frequency range up to 100MHz and you can live with a -65dBm to +5dBm range (attenuators can be accomodated) there is a cheaper solution that works fine:

A Small RF Power Meter with SCPI Connectivity

It uses an Arduino and an AD8307 to do the trick, and it works fine. Total cost is less than 100€, not too bad for an accuracy of 1dB. Its all USB powered and can be used by standard SCPI tools and libraries (uses NI VISA).

An Automatic Calibrator for Rigol DP832(A) Power Supplies

Do you have some Rigol DP832(A)s that are a bit overdue for their yearly calibration, but you dont want to send them in (>100€ + VAT + Shipping) or want to do a manual calibration (1h minimum) ? Then there is a smarter solution:

A SCPI-controlled calibrator that will coordinate all measurements automatically. Attach your DP832, a Keysight 34461 or better DMM, start a script – and wait ca. 10 minutes.


Done. See the link below for details:

An Automatic Calibrator for Rigol DP832(A) Power Supplies


A Generic Screen Capture Tool for SCPI Instruments


SCPI is like a haunting dinosaur lurking in all kinds of better and top-notch lab instruments. Unfortunately, the dinosaurs of different manufacturers all work differently if you as them to do a hardcopy and transfer it to your PC.

After fruitless attemps to do this with manufacturer software, I wrote my own little tool in Python that does the ugly work for some instruments from Keysight, R&S, Rigol and Tek. Click below to see the details:

A Generic Screen Capture Tool for SCPI Instruments

A sample screen is shown here:


and the good thing is that it can also do screenshots from instruments without a screen and/or missing SCPI hardcopy commands !

Homebrew SCPI Instruments



Are you living in a SCPI-infested lab world where a lot of standard equipment is used to be remote-controlled by SCPI, and now you want to automate an instrument that you have made, in exactly the same way, preferrable by some high-level language like Python or the like ?

Then its time to create some SCPI-controllable parts of your own. Here we are:

Click here to see how to Homebrew SCPI Controllable Instruments with Arduino Controllers

Power Supply Impedance Measurements Using an AP300 Frequency Response Analyzer

After testing a Keysight E5061B-3L5 and an Omicron Bode100 VNA, I got another LF frequency response analyzer (not a full VNA) on loan, the AP Instruments AP300. This unit has a low frequency limit of 10mHz, way lower than the other instruments. It looks like this:


I use these units to determine the output impedance of linear, low noise power supplies.

Click here for a Power Supply Impedance Measurements Using an AP300 Frequency Response Analyzer …

Phase Noise Measurements of Homemade and Commercial Oscillators and Signal Sources

Having an FSUP Phase Noise Analyzer on loan for an oscillator project (thanks N1UL !) I had the chance to check the phase noise of some commercial and homebrew oscillators and signal sources.


PhaseNoise10MHzRubidiumStandardLPRO1Hz1MHzFSUPThis a an EFRATOM LPRO101 Rubidium Standard. I also measured a commercial MillRen OCXO, a GPS standard, a Keysight N5171B RF signal generator and a RIGOL DG1062Z.

Click here to see some Phase Noise Measurements of Commercial and Homemade Oscillators …

Silly Circuits -Unusual Behaviour of Crystal Oscillators

Normally, crystal oscillators are standard components, used thousands of times without too much engineering attention necessary. If it comes to high quality crystals, a lot of unexpected effects can occur, like generating several nonharmonic frequencies at the same time and even chaotic behaviour.

here in the time domain:

Click here to see some Unusual Behaviour of Crystal Oscillators …

Using the Keysight AutoProbe Interface in Your Own Projects

As an owner of some Keysight equipment I wanted to use some probes intended for the Oscilloscope AutoProbe connector on other test equipment like VNAs or spectrum analyzers. I asked how to do this at the Keysight forums, but nobody had an answer for me there except that it does not work.

OK, lets homebrew something and see how far we get.



To make a long story short, it worked after a while of research and testing.

Click here to See Using the Keysight AutoProbe Interface in Your Own Projects …