Latest new & things

New TLE of Aenaes (and friends) from DK3WN makes collection a lot easier. These are a couple of packets I just received:

APRS: KE6YFA-1>CQ,TELEM:4341455255531D0040020008090B020D072837050000001000F075000070130049C08F13411D4F
APRS: KE6YFA-1>CQ,TELEM:4341455255531D0040020008090B020D080037050000001000F075000070130049C08F1341D581

Which means that the port to GnuRadio 3.7 now seems to work - it took a lot of effort due to the relocation of a whole bunch of classes from one module to another (and also some bugs the GnuRadio maintainers introduced on the way). So after a week of effort I'm back to where I was with version 3.6, and don't really have anything more to show for it! Ho hum.

I did order some better crystals for my RTLSDR receivers - although as they're at 14.4MHz I need to do some more work in order to get them usable - but it should cure the really crap frequency drift I see with the recent received I purchased.

I've just ordered a Rigol DS1052E oscilloscope - I'm not expecting much, but it should take some of the guess work out of some of the things I do! Now I just have to win the lottery and I can get that VNA I need!

I now have some test data (from HO-68) which I can use to evaluate the new CW mode in MultimonNG.

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!

Aeneas

From the pass that just occurred (20:25 GMT):

AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617132808050000001000F07500007013004930C617423C83
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617140008050000001000F07500007013004930C6174285FE
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617141408050000001000F07500007013004930C617425306
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617142808050000001000F07500007013004930C617423807
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617150008050000001000F07500007013004930C61742E9C9
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617161408050000001000F07500007013004930C617428B68
AFSK1200: fm KE6YFA-1 to CQ-0 via TELEM-0 UI  pid=F0
4341455255531D0040020006040B0617162808050000001000F07500007013004930C61742E069

Testing with NOAA-19

I've got my software to the point where I can just click on a button and it will record (and perhaps decode) that pass. I have come to the conclusion that my Doppler corrector isn't good enough, so I'll have to re-engineer that. I don't support all the modes & modulations & baud rates that I need yet, but am working on it. Some, for example, APT I'm still having to do by hand. When the weather cools down, I'll start to design a much better Gnuradio backend which will allow me to construct & control flow graphs better than the GRC ones I'm currently employing. Anyway, to end on here's a pretty picture that I just decoded from NOAA-19 on my RTL-SDR dongle: