Topics and links for the broadcast of 21-03-2021 11:00 am (CEST)

How Amateur Radio Fans Decoded SpaceX's Telemetry & Engineering Video

Over the weekend amateur radio tinkerers in Europe managed to decode some portions of the telemetry data broadcast by the second stage of the Falcon 9 when it's in orbit. This data was in a somewhat standard format, but decoding still required some custom tools to extract the bitstream from the signal and then some guesswork to figure out the exact format. There's still lots of unknown data, but most interestingly this gave access to the engineering cameras including one showing the interior of the liquid oxygen tank. Scott Manly displays in his youtube video how they did it in simple terms. More inside information and how telemetry decoding was done can be found on on the website of De telemetry data en video footage was not encrypted.

Where Does 26mV Come From in r'e in BJT transistors?

One number that pops up a lot in BJT calculations is the 26mV used to calculate the base-emitter resistance. Where does that value come from? In The Offset Volt youtube channel a good explanation is given where this value comes from. I highly recommend his channel for alot more on this topic. You can watch the explanation here.

Incoming news from pc5d

From the RSGB news bulletin:
The RSGB has an updated version of the RSGB EMF calculator
published on the website In this version, the cover page has been changed in response to comments and suggestions from people who have tried to use it. More work needs to be done to update the frequency dependent antenna data and we would appreciate volunteers to help with this. The program has also been updated to use the Ofcom calculator v0.1.2, which is published on their website. This distinguishes for frequencies less than 10MHz.

ARISS amateur radio station
Amateur radio on the International Space Station is operational again, after a spacewalk on the 13th where the cabling of the Columbus module was worked. The Columbus amateur station, that usually using the callsign NA1SS, the main one is ARISS amateur radio station used for school contacts and other activities.

Last weekend the conditions were moderate due to a Kp index of 4. Later in the week the earth's magnetic field was calm again. For the DX, the focus is mainly on the Russian DX pedition A25RU to Botswana. They will be there until March 26th and will operate all modes including CW, SSB and FT8. March is a good month for these North-South trails and forecasts indicate that 1600-1800UTC is probably the best time for a contact with Botswana at 30 to 17 meters. Next week, NOAA predicts that the solar flux index will rise slightly to around 80 and that we will see troubled geomagnetic conditions this weekend. The maximum usable frequencies will vary between 7 MHz at the end of the night, increasing just above 14 MHz during the day. The connections on VHF to England may improve in the coming days.

Echolink for windows 2.1 is now available

16 March 2021: After a 14-year hiatus, we are pleased to announce that EchoLink for Windows version 2.1 is now available. Please see the Download page to download. The changelog is shown below on that page. More in information can be found in the news section of