I had bought a cheaper DVB-T SDR dongle a few years back when I first started flirting with HAM, but it's just got a little MCX snap-in connector and it died, so I went and got the RTL-SDR V3 sold by the blog. I picked up lots of interesting stuff even with the little whip antenna, was getting bord with Covid shut-in, and decided to try it again, and found out it was dead.
I've got the downconverter so I could pull in AM and SW, but the signal strength was crappy. I guess my Discone is limiting me there.
I set up some ADSB software, but with Covid, and a minimal military presence around Milwaukee, (The 128th Refueling Wing out of Mitchell seems to mainly drill in summer?) there's hardly any planes to track. I know it was working though, as one small regional jet went by to the north of the city.
Right now I've gotten the bug to pull down some NOAA satellite images, but haven't had any luck. Mainly because the discone I almost died putting on my 2nd story roof is ill suited to the frequency and polarization. Although, unless it was an air-pager going off right at the time of the passes and faded in and out at the right times instead of just cutting off, I've seen two signals, but didn't have the software, or the soundcard virtual pipe working right. Now that it's working right, I haven't seen any signals. I think the satellite needs to be almost dead overhead when you've got the wrong antenna.
I'm flirting with building a QHF helix antenna tuned to around 137Mhz to pull in the NOAA images, but don't know if I want to invest in the time and materials when I'm going to pull and image, say "Neat! I did it!" then likely just move onto something else. So I've got an LNA (low noise amplifier) on the way to see if it'll boost my gain any. Throwing money vs. time at the problem for now. For all I know I'm doing it all wrong. All the advice I've gotten is the LNA should be just after the antenna, but I'm not interested in getting back up on my roof, plus despite being powered by the bias-tee meaning I don't need any power up there for it, it's still not really an "outdoors" unit. So I don't know if I'm wasting my time putting the LNA in my house near the PC or not.
If you can tell, I'm not well versed in RF theory, I remembered enough to pass my Tech exam, then promptly forgot a lot of it. And I fully admit I tend to jump into hobbies and muddle randomly until I can do the "cool thing", then lose interest.
I've got a buddy that lent me a big box o' ham stuff when I got my license, and an SDR dongle is one of the things in there.
I don't understand the function/purpose of it, nor how an antenna gets into the mix. Care to 'splayn the appeal, utility, and infrastructure of the setup?
Overall, the appeal to me is that this little $20 USB dongle and some freeware from the Internet does what a $2300 radio does. Minus transmit of course.
First you download something called Zadig, which gives most any SDR dongle it's driver and input into your PC.
Then you download SDR# which gives you a big fancy tuning screen with the FFT (Fast Fourier Transform) waveform on the top showing you peaks at different wavelengths where there's signals. The bottom half is the "Waterfall" the rainbow colored graph showing the signals as they go by in time. Because unless it's a constant transmission, the peaks come and go, and you want to see the colored dashes or shapes moving down the screen of what was happening so you can go tune there when it shows up again.
The antenna is where it gets kind of complicated. Because Physics, there's rarely one do-all antenna. Antenna design and types is as deep and complicated a subject as guns is at least. Different antennas are needed for different frequencies etc. And it depends on your house, where you're set up, and the land around you. Assuming your house isn't an RF proof steel box, and you just want to "get started" and hear something interesting enough to be worth your time and effort, a medium sized car antenna for HAM handhelds will probably let you get started and tune in commercial FM, nearby air traffic, non-digital non-trunked commercial and municipal radio traffic, and hear the HAM's talking on 2 Meters and 3 Centimeters.
After that, there's all sorts of side-quests you can get into, like the ADSB where it pulls in signals from aircraft going by and puts them on a map with their flight info. Or you can set up digital decoding software to turn digital municipal and commercial radio into something you can hear. Or if it's a trunked system, you set up a second SDR dongle so the software can pull in the two frequencies that needs at once. Or like I'm interested in, polar orbiting NOAA weather satellites just constantly spam images of Earth and clouds down as they pass overhead.
This article has a good list of things you can do with a SDR dongle.
https://www.rtl-sdr.com/about-rtl-sdr/
