Monday, 28 November 2016
Stop the press! The latest add-on to the SMA Simple Spectrum Analyser opens doors to "on-the-field measurement map creation" - probably a unique feature!
So why am I driving around the block with my laptop on the passengers seat, an antenna glued on the car, a Bluetooth GPS receiver on the windscreen and the "138MHz-4.4GHz 35M-4.4G USB SMA Source/Signal Generator/Simple Spectrum Analyzer"?
Well, for ages I was wondering why field meter manufacturers did not implement a logging function with a GPS stamp on it, so that the measurements could be mapped. Even field meter with GPS support are using the position data to just calculate the setup of satellite dishes - at least the field meters I know.
So I put hands on a long time project idea and added it to my own software!
First new change: on the setup tab one can now configure a GPS receiver. It must be connected via serial port (virtual or not, doesn't matter) and support the NMEA protocol (most do). The software has so far been tested with a Garmin eTrex Venture and an (old) Asus BT100. It should work with any Bluetooth or RS232 GPS receiver and apparently there are apps that turn your Android mobile phone into such a GPS receiver (not tested, yet).
Now one can go to the spectrum tab and use the spectrum in regular way, but it is possible to start a logging on the "Marker 1" frequency. If the GPS logging checkbox in the setup tab is checked, then the consecutive measurements are saved with a GPS stamp.
And now the most spectacular functionality (probably unique): once the logging is finished, the desired frequencie set with "Marker 1", you can go to the "Log on Map" tab, load the log file and have all measured points listed in a list box and...
...have the points rendered in colour code on Google Maps!
Pause the mouse icon over one of the coloured measurments squares and the dBm value is shown.
Here is the result of my quick log of the local LTE transponder at 791MHz:
Much more development is required and I have lots of ideas to further improve this kind of functionality.
Before you all get too excited: all of this is highly beta and this release has not been made public.
If you are a field meter manufacturer and are interested in this technology - contact me!