I just tuned in to hear a polka show.Is this the site you found it on? http://boomerthedog.com:8073/ Sounds like 690 has conservative talk on it, at least right now.
The grid square its located in centered around Westwood. The SDR could be run by whoever runs the station. Otherwise, if its a Part 15 it's got to be close to that receiver. Maybe that's their streaming setup.I am just getting static on 690 kHz in the Oakland neighborhood of Pittsburgh. From digging a little online, the only record of "AM 690, Underground Radio" is on a cached page of a website that is not currently or no longer active: Affiliate Stations - Radio Survivor
It is under the part 15 header:
View attachment 3397
The highlighted link opens a web player page that seems to no longer be operational.
Perhaps the individual or group hosting the SDR you accessed also has their own part 15 station. Do you have any indication of where abouts this remote SDR is located?
Very interesting! Thanks for checking that out. Since "AM 690" is on a tab on the SDR, we can pretty much conclude it's also at the transmitting locationOut of curiosity, I drove around and found it! It was definitely playing polka within the past 45 minutes.
I think I even identified the house it is coming from. Not going to identify an address here of course. The station seems to have an effective range of about 0.2 miles, so not a whole lot, but potentially exceeding FCC part 15 limits, where the effective range should theoretically be about 200 feet.