2019-02-17 Sunday ISS pass with good results 2 months ago
Sunday had less time to be at the radio for ISS passes but one pass was ok. It started with the end of one image, one full image and the start of the next image. The audio recording of the whole pass is included.
Listen to audio attachment:
2019-02-16 One more ISS pass with good results receiving slow scan TV 2 months ago
After hickups in recording audio from the radio on two previous passes I rebooted the whole system (it was nagging about a reboot anyway) and I received two more partial images. Thanks to ARISS Russia team member Sergey Samburov, RV3DR for making this possible!
2019-02-16 Second ISS SSTV pass: more results 2 months ago
Second pass of the International space station gave me one partial picture and one complete (with some noise).
2019-02-16 Received SSTV from the ISS 2 months ago
In this weekend there are extra slow scan tv (SSTV) transmissions from the international space station (ISS). The ISS moves across the sky when viewed from earth so I calculate beforehand when it will pass across the sky and what the trajectory will be. I woke up in time to be outside for the first one. A low pass over the horizon and most of the pass matched a pause between transmissions, so not much image received.
2019-01-08 Amateur radio resolutions for 2019 3 months ago
The last time I did those was in 2017: Reviewing my 2016 amateur radio resolutions, and the new ones for 2017 and the hindsight results for 2017/2018 are:
The Sotabeams newsletter had an item "Setting your targets for 2019" which had some nice ideas and which triggered me to write this post. Things I want to try :
- Improve the holiday/portable setup with solar power and a lightweight multiband inverted V
No solar power (due to costs) but the portable setup is improved and tested: the fiber mast I bought for playing radio from several locations including amateur radio from a local park. Now to find more time to actually use it.
- Keep doing the digimode contests
That part went better in 2017 and I had less time and/or energy for contests in 2018. Also in 2018 the interference situation got worse. So my net results in contests improved in 2017 and got worse in 2018.
- Maybe those satellites
I tried at least receiving them a few times, but no contacts yet.
- Get a 2m/70cm vertical antenna on the roof of the dormer
It's there, it has already been upgraded to a bigger antenna with higher gain and it's mostly used for 2 meter FT8. But also for actual talking to other radio amateurs sometimes.
- Keep learning morse!
- Get more countries on more HF bands in the log
- Moonbounce on 2 meter
- Those digimode contests, and maybe a few phone contests
- Operate HF outside
- At least one satellite contact
2018-06-27 Recorded the ISS contact today 9 months ago
Today was an ISS contact with Werner-Heisenberg-Gymnasium, Leverkusen, Germany and Schickhardt-Gymnasium, Herrenberg, Germany and most of the contact was going to be within range for me and it was at a usable time. So I set up gpredict to track the ISS and the receive frequency and set up audacity to record the results. Which weren't great since 2 meter reception is now influenced by recently installed solar panels on the house next door.
Listen to audio attachment:
2018-05-25 Going full duplex with amateur satellites, part 13: receiving a linear satellite transponder / SO-50 without the preamp 10 months ago
This evening another try, this time without the preamp. And tried receiving a linear satellite transponder. This makes things even more complicated as I have to look at one display (gpredict) to have an idea where to aim the antenna and another display (gqrx) for the waterfall display. Maybe both can be on the same screen with a lot of resizing. The first pass I tried was a pass of the FO-29 satellite which has a linear transponder. It was not a very high pass so all reception was through a house. I did hear morse first, and later saw signs of USB signals in the passband. Signals were weak and noise was high. I was almost able to understand one callsign, a 9A.. callsign (Croatia). The other pass I tried was a pass of the SO-50 satellite which is a narrow FM satellite. Signals were weak for narrow FM so I had to keep turning the arrow antenna to get the polarisation right. I could hear spanish and english callsigns. I recorded the SO-50 pass and noted the audio looked very distorted in audacity. Maybe I can improve the audio somewhere in the chain and get things better.
2018-05-24 Going full duplex with amateur satellites, part 12: picking it up again 10 months ago
So last year I wanted to get back on amateur satellites and bought some hardware that would enable me to go full-duplex: receive and transmit at the same time. The most important part is to get the receive side working. This evening had a pass of the SO-50 amateur satellite and a pass of the Fox-1D satellite right after another (with some overlap). And it's dry and a reasonable temperature to be outside with laptop, preamp, rtl-sdr stick and arrow antenna. Signal levels on narrow FM are still very faint and hard to hear, so I guess I am at the limits of the rtl-sdr for weaker signals, even with the preamp.
2018-05-01 Getting amateur satellite contacts into LoTW correctly 11 months ago
A very good bit of info just flew by on the amsat-bb mailing list: Logging Satellite QSOs with Logbook of the World - AMSAT-NA. Complete with screenshots and needed steps, how to create an ADIF file (which I could import into CQRLOG) with the satellite-specific fields set to the values needed by LoTW to make it a valid satellite-contact. CQRLOG has no support for satellite-specific contact information, so for me the workflow for these contacts would be to create an ADIF file as above in LoTW, upload it, and import the ADIF file in CQRLOG and not upload it from CQRLOG. Now to find time, energy and nice weather to get on the satellites again.
2017-12-02 Preparing gpredict for AO-91 Fox-1B RadFxSat 1 year ago
Although reports are showing up that AO-91 has the usual 'zoo' when it's over southern Europe I still want to prepare for making contacts on interesting passes. So I dove into adding satellite transponder details to Gpredict again. According to [amsat-bb] AMSAT-OSCAR 91 identified it is Norad object 43017. And when Nico Janssen finds a satellite using his methods of doppler-curve fitting it's a very good indication it's the right one. So time to create a .config/Gpredict/trsp/43017.trsp with the right frequencies and details:[Fox-1B trsp 67 Hz PL] UP_LOW=435250000 DOWN_LOW=145960000 MODE=FMNow to find a pass at a for me usable time.
2017-11-08 Trying to receive Fox-1A (AO85) telemetry 1 year ago
I decided to try to receive telemetry data from the Fox-1A (AO85) satellite to prepare for receiving telemetry from the new RadFxSat right after launch. The FoxTelem program is ready to receive data from all the Fox series satellites so this was a good way to test my receiving setup. This afternoon there was a reasonable pass so I decided to give it a try. With the FT-857D radio tuned to the downlink frequency 145.978 MHz in FM packet mode. While I did hear the conversations on the satellite in the noise the program did not seem to receive anything. And then I noticed the sound display in the program reacted strongly when I tapped the microphone connected to the mixing board. I chose the wrong audio device. I have two USB audio devices connected to the computer, one feeds audio from a mixing desk and one feeds audio from the radio. Normally I can keep them apart but FoxTelem was only showing one of them. The solution was to set FoxTelem to the audio device 'default' and use pavucontrol to switch the input of the application to the right USB audio device. But by the time I figured that out the satellite was already too far to receive any useful telemetry data. Time to find another nice pass with useful elevation (above 10 degrees) to try this again. And it's a good preparation for the launch of Fox-1B.
2017-11-07 Waiting for the launch of RadFxSat (Fox 1B) 1 year ago
The subset of radio amateurs that is interested in amateur satellites is waiting for the launch of RadFxSat / Fox 1B. The name 'RadFxSat' stands for 'Radiation Effects Satellite'. The primary mission is in cooperation with Vanderbilt University ISDE studying radiation effects on commercial off the shelf components. The amateur radio mission is a FM U/v repeater with CTCSS, which means it can be used by radio amateurs to make long distance contacts. As any new satellite, the first phase after launch is a lot of testing before any experiments or radio services are started. During the testing phase the satellite will transmit short radio messages (audio with data mixed in as low frequency tones) with telemetry data. By receiving the telemetry data and forwarding it to the operators radio amateurs can help the testing. This telemetry includes voltages and temperatures which allow the operator to find out if the satellite operates as designed and whether the power budget (generated power from solar panels minus used power) is good. To receive telemetry from the Fox series satellites and forward it a program has been developed named FoxTelem and I am glad to see a linux version is available. This allows me to receive the satellite unattended and forward the data. I will at least try to participate in the 'Launch and Early Orbit program' during the first few days. Current launch date is planned at November 14th. More information:
2017-07-24 Last night receiving ISS SSTV images 1 year ago
And a third night. I used the timed recording option of audacity, which in the current linux version does not offer the option to set in advance how to save the project. This time I 'only' recorded for 7 hours, and was able to save the project afterwards without needing a recover. But on reloading the saved project audacity complained about some internal error in it, and it still had the problem of assuming 44.1 kHz sampling while showing the project sample rate as 48 kHz. Anyway, images decoded from the audio and I even recieved a few new ones.
2017-07-23 Another night of receiving ISS SSTV images 1 year ago
On the night from Friday to Saturday I had the whole setup ready to receive more ISS SSTV images. And nothing was received since I had the antenna unplugged during Friday because of thunderstorms and forgot to plug it back in. So when I found that out I put a note on my desk with 'Antenna unplugged?' which can be a reminder to unplug it when I'm done or plug it in when I want to receive something. On the night from Saturday to Sunday I plugged the antenna in and let the whole setup run again like on the earlier run on Friday Received slow scan TV images from ISS while I was sleeping. To make sure I had the antenna plugged in I tuned to 145.750 MHz where I can hear a distant repeater faintly. Again audacity hung after the recording, and this time on recovery it had some issues with the saved project. At first I could see and hear audio of SSTV passes but qsstv could not decode anything. In the waterfall display of qsstv it looked like the frequencies were too low. I had a thought that maybe something decided the samplerate was back to 44.1 kHz so I simply speeded the audio of an image pass up by 8.8435% and suddenly it decoded fine. In the end I decoded 11 images from the ISS SSTV project. Numbers seen 8, 10, 9, 6, 7, 8, 6, 4, 5, 6. And 2 images from nearby radio amateurs who weren't operating according to the bandplan... but at least did not interfere with the ISS SSTV transmissions.
2017-07-21 Received slow scan TV images from ISS while I was sleeping 1 year ago
I read about the current ARISS Celebrates it’s 20th Anniversary through SSTV Event and noticed the planned times weren't really compatible with my day/night cyclus. I know, as a hardcore radio amateur I should be up at the weirdest hours for rare events but I also like my sleep a lot and my wife really dislikes alarms at weird hours. Automation to the rescue: I decided to record all of a night of ISS signals on the computer with audacity and decode images from it later. The computer adjusted the radio for doppler using gpredict. Since I don't have an automatic rotor for satellite antennas I used the VHF/UHF vertical. This may seem strange but the weakest signals from ISS are when it is right above the horizon (which is when the vertical has the best reception). And as noticed on earlier SSTV events that compared to other amateur satellites the ISS has a strong signal. So I left it running for a night and checked the results afterwards. The result was a 9 hour recording and audacity decided to hang after stopping the recording. I made a backup copy of the audio data just to be safe and restarted audacity. Luckily it recovered the project fine after restarting. With a recent version of qsstv I decoded the recorded audio and searched for ISS passes in the recording. The result is 13 decodes in one night. It turns out it received audio from a number of low passes that I did not see in gpredict because I have gpredict set up to skip low passes (those that don't come above a 20 degree angle above the horizon). But the strong signals from ISS make those show up in my radio anyway. Decoded and seen the numbers sofar: 11 (partially), 12, 9, 10, 9, 10, 9 (partially), 9, 7, 8.
2017-05-08 Going full duplex with amateur satellites, part 11 : Tried an XW-2A pass, heard vague signals, no contacts 1 year ago
This evening the only amateur satellite pass at a reasonable time was by the XW-2A satellite, part of CAMSAT XW-2 Satellites - amsat UK and I only heard weak signals which sounded like other radio amateurs tuning their transmitters/receivers but I never heard something like a voice. Or my own signal when I tried transmitting.
2017-05-07 Going full duplex with amateur satellites, part 10 : Still no contacts, investigating AO-85 (Fox-1a) 1 year ago
Passes of amateur satellites aren't always at times that are compatible with other things happening. But the discussion about AO-85 on the amsat-bb mailing list also had some details about the satellite and I also found AO-85 Twist Trick and Other Hints - Spacecomms which explains:Apparently the epoxy caused a change in impedance which essentially “detuned” the antenna. It makes the bird appear deaf. A workaround is to twist the Arrow antenna 90 degrees when you transmit. That is, rotate the antenna until the receive signal is “peaked” and then rotate it 90 degrees when you transmit and back again to receive. The downside to this is if you’re working full duplex when you rotate the antenna 90 degrees to transmit you will often lose the downlink signal and not be able to hear yourself. In my experience I only have to do the twist trick in the beginning and end of the pass when the bird is farthest away. Another fix is to just use more power, but if you only have an HT that’s usually not an option.This, combined with the frequencies up and down being slightly different from the planned frequencies explains the weak signals I hear upon receiving and the difficulty I had getting into the satellite. This evening had a pass of AO-85 which did not leave me time to drag out the whole setup, but I was able to bring the arrow antenna and a handheld radio to check reception to see if the frequency was correct, including doppler correction. It was correct, but reception is indeed quite sensitive to the orientation of the arrow antenna.
2017-05-01 Going full duplex with amateur satellites, part 9 : Filtering the reception, in theory 1 year ago
I decided to share my woes of the receive side going deaf (receiving nothing) when I transmit with the amsat-bb mailing list, together with a description of the whole setup. The suggestion came from Eduardo PY2RN to not use a preamp and have filtering so the transmitted signal cannot get into the receiving side. I pondered this for a while and realised I already have a filter: the diplexer on the arrow antenna. So to receive on 2 meter and transmit on 70cm I connect the transmitting radio to the 70cm antenna and connect the receiving radio (the rtl-sdr) to the 2 meter antenna via the diplexer, and put a 50 ohms terminating resistor on the 70cm connector of the diplexer to make sure it still shows the right impedance. In a simple test this works, transmitting now has a lot less influence on the rtl-sdr (it's not completely gone yet). I haven't had a good satellite pass yet to try this out.
2017-04-29 Going full duplex with amateur satellites, part 8 : No real contact yet 1 year ago
This evening had a Fox-1A (AO-85) pass at a reasonable time so I decided to drag the entire setup outside and try my luck at a qso. Reception of Fox-1A was bad (maybe I'm somewhat off-frequency) and the major dissapointment was that the receiving side on 2 meter via sdr got deaf when I was transmitting on 70 centimeter. That's not supposed to happen, the whole reason for the full-duplex setup was to be able to hear myself on the downlink. Anyway, the recording of downlink audio went fine this time so there is a full recording of what I heard. It was a Northwest-Southeast pass which means it took a while before I heard anything because northwest is over the houses. Callsigns heard in this pass: DO3EXE, IZ5ILX, 9A2EY, IZ3KLF, Something with F2D I completely can't decode and "Mr Olla". My best guess would be a retry on SO-50, FO-29 or AO-73.
Listen to audio attachment:
2017-04-23 Going full duplex with amateur satellites, part 7 : Recording downlink audio 1 year agoOlder news items for tag amateursatellites ⇒
This evening I thought there would be a nice Fox-1A (AO-85) pass but gpredict on another computer showed totally different predictions. Pondering that difference made me suddenly remember AO-85 is still not part of the 'standard' set of Kepler data because it's close to some militairy satellite. The data is available through other sources, I use TLE | Amateur radio PE0SAT and updated from that location. The 'nice' AO-85 pass near 22:30 localtime shifted to 'way too late', so I looked for other satellites to at least try recording downlink audio. I saw passes of HO-68 and UO-11. So I created the whole setup with audacity recording audio. Using pavucontrol I adjusted the recording flow of audacity to record 'Monitor of Built-in Audio Analog Stereo' and indeed audacity was recording the same as I heard on my headphones. But no signal from the satellites was received. Checking the Amsat Oscar status page shows both haven't been heard by others either. So I recorded noise, but I recorded the right noise.