Balloons & things

It has been a bank holiday this weekend - and weirdly hasn't been too wet. Well, actually it poured with rain on Saturday. Anyway,  there were a number of high-altitude balloon launches on Saturday and again today. More information can be found here but I don't know where that page gets archived. Another good link is here. I could pick up all 4 balloons from today when they got reasonably high - and when I switch my yagi to be in V pol - d'oh! (Using one of my RTL_SDR receivers). I'm having difficulty in getting dl-fldigi to decode the output via pulse audio (it works if I save the stream to an 8k samps/s WAV file and then replay that in dl-fldigi) - I'm sure there are better ways to connect 2 programs. I shall explore further and see what I can do. its not helped by my recent transition to GnuRadio 3.7 which seems to have broken a lot.

In other areas I've got my stepper motor working with my beaglebone black - now just have to get the rest of the engineering sorted.

ISS Pass

A photo of the ISS pass last night. Just put my camera on a wheelie bin pointing up with a 10 second exposure and crossed my fingers! Of the 3 photos I took, one has ISS going through it.

The photo won't win any prizes, but its good to see what can be done with very simple equipment. If only it had been clear during the Perseids a few days back.

I got a couple of new RTL-SDR USB sticks last week and am currently roughly calibrating them (estimating the frequency offset error and will look at the noise figure to compare with my other USB sticks - although the latter is tricky due to the lack of equipment I have.)

Software Announcement!

The GroundStation software I've been working on for the last few months is now available from github here - below are a couple of screen shots of the realtime view of where the sats are and the pane on the right shows what frequency they are at (x-axis is frequency in MHz, y-axis is time in hours from now).

The second image show that I've select a part of the RF spectrum to capture (width determined by the fact its just a RTLSDR receiver).

When the times comes along, up pops an appropriate 'channel' which decode the signal (with real time Doppler corrections) - all by the magic of GnuRadio (and a fair amount of swearing!!). Its still pretty rough around the edges (and its very polyhedral....) but has got a fair amount of potential - so by the 10th rewrite it'll be great!

This week I also got my beagleboneblack running Debian and now happily streaming my RTLSDR dongle back to my desktop.

This looks like a very nice bit of kit, HackRF I look forward to getting mine.

Updates and things....

Here's the latest I've got from Aeneas from the pass today at around 13:45UTC:

AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006190B0611391424050000001000F07500007013004900398341A5C5
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006190B0611392824050000001000F07500007013004900398341CEC4
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006190B06113A0024050000001000F07500007013004900398341C764
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006190B06113A1424050000001000F07500007013004900398341119C
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006190B06113A2824050000001000F075000070130049003983417A9D

And here's some from the pass yesterday (3rd Aug) at around 13:30UTC:

AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006180B0511271424050000001000F075000070130049C0004D41AD4C
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006180B0511272824050000001000F075000070130049C0004D41C64D
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006180B0511280024050000001000F075000070130049C0004D410E83
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006180B0511281424050000001000F075000070130049C0004D41D87B

also STRaND-1 has been a strong signal (25-30dB above noise), but I've not yet sorted out the decode of it yet.

I've continued to work on my groundstation software and now have a working Doppler correction gnuradio block. I've made a bunch of improvements to the GUI and should have something pushed to github in the next month or two. One of the features I've added is a frequency against time plot which allows you to have multiple channels receiving different sats with different modes & Doppler corrections applied.

I'm still working on getting my beaglebone black working with my rtl-sdr receiver to make a PoE powered remote device - the main issue I'm having is updating the OS to be debian so I can easily put all of the dependencies - I know have a way forward with this - but not the time to do it!