HI all,
I read a post on here a while back where someone was recommended to build a station with an omnidirectional antenna equipped station as instructed here: https://wiki.satnogs.org/No_rotator.
Surely with such a low gain system you can’t access the majority of cubesats with amateur radio beacons? Would it only be possible to receive weather information? Or are there steps you can take to access amateur radio beacons on cubesats with this station?
Thanks for your time,
Lorcan.
It is true that a fixed station is limited but that doesn’t mean to say that it is not useful. A turnstile antenna or QFH will have a limit on usable horizon. I use a simple turnstile and can clearly decode vhf downlinks for voice, data (telem and weather) and CW.
Position of antenna, using LNA’s etc will all play a part but what works for me may not work for you. This might be useful reading
Are you looking at building a station?
I have been using a omnidirectional Multi-band antenna for my station for a bit.
(One not designed for satellite stuff.)
And I have had a bit of success. https://network-dev.satnogs.org/stations/95/
Not as much as if I had a turnstile tho
Thanks for your reply.
Yes I am building a station as part of a University project. I had initially planned to construct a ground station with a directional antenna and using the SatNOGS rotator. However due to a number of unforeseen events including the software not being finished, I’ve had to opt for a fixed antenna. I thought about using a fixed directional antenna, however I sort of screwed up and ordered an omnidirectional UHF antenna. Dumb, I know. I should have got a VHF if anything, but I can’t send it back so it will have to do. Currently planning on building an eggbeater VHF to at least give me the option.
The station will be somwhere between 10 and 150 m above ground using a 6.5dBi UHF omni with an LNA4ALL and RTL2832U R280T2. Could you give me some advice on what I could pick up?
thanks for your time,
Lorcan.
My station (#32) uses the antenna presented in this thread which is a UHF Parasitic Lindenblad.
It gets several signals from satellites and have decoded some of these as you can see here.
Except the antenna the rest of the setup is similar with the no-rotator one.
My station (lucky #13) also uses an omni-directional turnstile for 137 MHz. It is even shadowed by house and tall trees, nevertheless, it regularly receives both voice, CW and PSK from amateur satellites and cubesats.
I don’t even use LNA, just antenna connected directly to an Airspy R2 
This is very handy. What kind of gain is your antenna getting?
Thanks again.
That’s very encouraging. I’ll have to build a VHF antenna though. I used up the last of my project budget getting a 6.5dBi UHF antenna foolishly enough.
Thanks for the info!
A UHF ground station is useful, a VHF turnstile could be made without too much bother or you could try this. I need to make one of these to give a comparison though
Thanks I definitely plan on giving it a go.
However, I have to construct a link budget as part of my project and I’m really struggling to find accurate information on the antenna gain of the spacecraft and their transmitter powers. I know that these antennas in combination with an LNA4ALL will work. You all have proof it works, however I have to be able to prove it in numbers too. Any leads on UHF workable sats and info on their antennas?
Thanks all.
Which ones are you really keen on using?
Anything really! Anything at all
I would go for a NOAA first off. I used a RPi2 and £3 rtl-sdr and a really easy dipole like this one which I made from a bit of old wire. The results were actually pretty good for a simple set up. It proved at least that the software was running and the hardware did at least a bit of a job.
Now I have a turnstile and the results are way better. RadFxSat and Funcube are perfectly readable from my QTH with the antennas in the loft
I concur.
I just built and installed a V-dipole antenna (http://lna4all.blogspot.de/2017/02/diy-137-mhz-wx-sat-v-dipole-antenna.html)… literally an hour ago.
The build is super easy and cheap as chips. The most difficult thing about the whole installation was crimping the tiny little mcx plug.
I’m not sure how well it works yet, but it does indeed prove that the RPi and SDR dongle are working.
I plan to run it for a week or two before upgrading to a turnstile. Baby steps
Here is a turnstile design with radiation pattern plots:
and here is the dope on a quadrifilar helix design:
Enjoy!
Herman
Thanks Herman, I’d not seen the QFH pattern before and its pretty unusual. I keep meaning to build one but other things get in the way