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Assorted ramblings from the developer

Simon G4ELI
Simon G4ELI

Simon's blog

Airspy HF+ & NOAA 18
Airspy HF+ & NOAA 18

Overhead Pass

Here's an example of the HF+ receiving the NOAA 18 APT weather satellite, the antenna is a log periodic covering 130 MHz to 1.3 GHz. The HF+ is very sensitive and very quiet - no mixer products, spurs, or artifacts at all.



Low Angle Pass

Here's an image from NOAA 18 but a moch lower angle - 13 degrees. You see noise on the image, but nethertheless an excellent copy.

Another Airspy HF+
Another Airspy HF+

My second Airspy HF+ arrived today fresh from the production run, below are a couple of screenshots from BBC Radio Cornwall on 103.9 MHz. In the main photo you see the packaging!

Well worth waiting for, no-one will be disappointed.

ACOM 1200s

This is what I want for Christmas. 1kW of pure loveliness, ideal for my SDR transceivers.

More information here.

New Wesbsite - Almost Ready
New Wesbsite - Almost Ready

The new website (that's this one) is almost ready - still testing but looking good. Sadly the old skins I used on DNN8 were deemed to not be secure, the company I purchased them from did nothing about this, so I bought news skines from and a new DNN system with DNN 9 was installed on a big DoDaddy farm.

Please have a look through the pages and report any problems.

Thanks - Simon

V3 Demo

Amateur radio operators on 80m. Recorded using a NetSDR and Wellbrook loop antenna.

ML&S, RSGB Convention 2017
ML&S, RSGB Convention 2017

Good to see SDRs being demonstrated at the 2017 RSGB convention, just wish I were there. Photo from a post on the ML&S facebook page.


Keyclicks on 20m

Lots of keyclicks on 20m!

2018 ARRL Handbook

It's nice to see SDR featured on the front cover of the 2018 ARRL Handbook - maybe 2018 will be the year of the SDR?

Recent Posts

  • V3 Beta Posted last month
    After three years the first beta is available, download from
  • V3 Server Posted 3 months ago
    Still early days - testing the connection between Cornwall and North Carolina. Streaming IQ data, working well. Enjoying the AM transmissions on 80m.
  • ISS Images, Dec 7th - 8th 2017 Posted 3 months ago
    In total nine of the twelve were copied during the afternoon passes on December 7th and 8th 2017.          
  • ISS Images, Dec 6 2017, 15:03 UTC Posted 3 months ago
    Excellent images copied from the ISS. radio is the Airspy HF+, 12 element X Yagi, satellite tracking etc. from SDR Console.      
  • LimeSDR Transmitting Posted 4 months ago
    I spent a day working on transmit support for the LimeSDR. This is by no means finished, but I'm able to say that it works. I have a few problems, Big spur at 0Hz, probably generated by a bad software mixer, Noise bursts when switching from receive to transmit.  The above are down to my own software, so I'll give myself a good kicking sometime and get this fixed later in 2017 or early 2018. Here we see the Upper Sideband (USB) signal as received with an Airspy HF+. And here's the TX panel from SDR Console.
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