As I understood it, you bought an RTL-SDR. So far as I know that has a fixed frequency span of 96 or 192 KHz. That was a major reason for my picking an RSP2.
FWIW It took me a while to get sound out of the RSP2. The software is "interesting".
Hmm I thought it could go in the Mhz range even even low Ghz, don't people use these for ADS-B? Maybe that's why it's acting funny, it's trying to go into that range since that's what I set it to, but then it's not really working. This is the one I got:
https://www.amazon.ca/gp/product/B01HA642SW/ref=oh_aui_detailpage_o09_s01?ie=UTF8&psc=1I also got a Ham It Up so I can play with the lower frequencies but have not hooked it up yet.
This might be the thread to ask. I have built a little transmitter (extremely short range, only a few meters, before you call the FCC on me) it is 915MHz. I plan to transmit FSK2 and a digital packet format @ ~ 10Kbaud. Is there a SDR that I could receive these packets with? I want to experiment a bit before building a matching receiver. The reason I have built my own is because I need an extremely unusual form factor.
I imagine it would work. May even be able to build a SDR as the receiver to decode it instead of a receiver from scratch (though a SDR will be more expensive and overkill probably). It's done for ADS-B (airplane transponder) and lot of other things. I guess you could do APRS too, though that's normally done via audio into the sound card. I'm a newbie myself so don't know much about how any of this is actually done though, just that it can be done.
Off work now, so played with this for a bit. Moved the setup in my office temporarily just to rule out server related noise. No change. Tried a USB extension as I read of people doing that, no go. Unplugging/plugging antennas changes the waterfall, but the sound always stays the same. It's like if what I'm hearing is not actually what it's producing. I just hear noise. Though I could have sworn I heard voices a few times, but sometimes that happens even when no radio is on.
I may have to put the whole thing in a grounded tin can or something. I'll play with that further another time. Tried all sorts of gain settings but that does not seem to change anything. The waterfall colours change to show more/less intensity but the sound is always just noise.
How far are you from a broadcast tower? My SDRplay RSP2 is deaf during the day because of a local 1 KW AM station less than 2 miles away. Works just fine at night when they are off the air. A notch filter is on my ToDo list. This is an issue with all SDRs. They cannot hear anything which is -6 dB * # of bits below the strongest signal in the passband of the receiver. For the RTL-SDR line the filters are quite broad. With the narrow BW of the RTL-SDR, you may not even see the interfering signal in the waterfall.
If you've got a signal source, hook that up, but make sure that you don't blow the front end. I had to build a -40dB attenuator for my RSP2 and monitored the signal level using a Tee to my scope before I connected the RSP2.
Hmmm there is a tower in front of my house, it has like 3 sets of cell sectors on it, and think OTA TV transmission. I know that if I plug a small piece of wire behind my TV I get a digital OTA channel in crystal clear HD while the others are snowy, so that TV signal is probably rather strong and may be from that tower.
The neat thing with the Openwebrx software is that the web interface works on my phone so if I get a wifi router I could technically set this up as a portable system and view it with my phone. Might have to do that and drive out of town just to see if things change. Too cold to do that now though. Like -35 out there.
I don't have anything in mind that can generate a signal though. Suppose a wave form generator might be my next toy if I want to get into this stuff.
This is the tower in front of my house if curious:
Guessing those straight antennas on top are TV. Or maybe lightning rods actually... The ones that look like bars off the sides are cell. Though there's a couple other possible antennas in there like that white round thing might be some sort of antenna.
Either there's something wrong with your software setup or your hardware is defective. I have several different dongles and they all work painlessly. I can pick up dozens of signals all over the band using nothing more than a small piece of wire or the included stub antenna. You shouldn't need anything fancy at all.
Thing is the waterfall seems accurate. It shows more color where I expect to see a radio station, but the sound is just static. Anything software wise I can check to troubleshoot this?
It also gets random spurts where I CAN hear stuff, but it's very short lived, like 1/4 second.
Guessing those straight antennas on top are TV. Or maybe lightning rods actually... The ones that look like bars off the sides are cell. Though there's a couple other possible antennas in there like that white round thing might be some sort of antenna.
Outside are sector antennas, long rods are lightning rods, white block is GPS receiver for cell timing, and smaller antennas are for 4G/LTE services. Looks like a LED warning light as well. Pretty much a common low density area cell tower.
Doesn't look like LED to me. I suppose it could have been updated but most of those beacons of that style use a pair of 610W mogul prefocus base incandescent lamps. I forget what the beacon is called but it has an official designation, they're made in that style by several companies.
Yeah doubt it's led. That one is the flasher, there is one mid tower that stays on. I monitor these for my own company, among lot of other things, and the bulbs burn out often enough and have to be changed. Would be a fun job to go up there. Idealy in mild weather.
Thing is the waterfall seems accurate. It shows more color where I expect to see a radio station, but the sound is just static. Anything software wise I can check to troubleshoot this?
Looking at your screenshots it seems to me that you are trying to receive wideband FM (about 100KHz deviation) with a receiver set to narrow band FM (12KHz). You will never get any meaningful audio like that.
Give it a try with SDR#:
https://airspy.com/download/
Actually I was wondering that too, if maybe I should be able to capture a wider range as the area of the waterfall that shows signal is much wider than what it's letting me capture.
Guess I will try Airspy or another software and see if it's better. Maybe I can also get access to the entire range since right now I need to change a setting and restart the server just to tune to a different frequency. Their readme file explains this saying that they did it that way since when you tune to another frequency it would affect every user if more than one person is listening... but that does not matter to me.
Reading further it really does sound like this does not support wide band FM. Weird. That was not my goal, but figured that would work too. I don't know of any other sources of radio I can look for, and because I can't figure out how to set a larger frequency range the only way to tune is to restart the server each time and manually input frequencies. Kinda defeats the purpose, as I was hoping I can get a waterfall that shows a large frequency range so that I can look for interesting stuff. Some of the SDRs on their site do have a larger selectable range though, so I don't get how they did that. There's got to be a setting somewhere that I just don't know about.
A lot of people are requesting to be able to update centre frequency from the web page though, so I think I'm going to wait to see if they do add that feature. Hopefully in the process they just increase the range of the waterfall too. I downloaded the airspy one but I just get a single file, I'm assuming it's a Raspberry PI image. I don't want to reload the Pi just yet so I'll wait and see. I can probably throw this back in my server rack now that I know that was not the issue.
I did pickup ADSB, it's basically just a constant beep. Will have to wait till there is no aircraft within a 300mi radius and see if it changes, just to confirm that what I'm getting is actually that. I have a separate ADSB receiver that feeds to Flightaware.
This is a fun one too.
Talk about one heck of a workout.
Another cool thing you can do with sdr is add it to your favorite old radio such as a TS 690s or an IC 706 with a Panoramic Adapter Tap Board and a rtl sdr of your choice. Those radio's in particular allow you to use CAT control to control your radio from your computer. Not only can you see the stations on hf but you can click on them and your computer will set your radio to that freq. AC8WP
I looking for an way to use an legal CB Radio with an ALE System.
So an SDR could be the best solution to listen to all Frequency and if an freq works the CB Radio tune into the Freq.
My Grandparents life ~500km away from our house the best place for an receiver station.