I have an RTL2832 and an Airspy/Spyverter setup hooked up to a 35' longwire antenna. I'm using GQRX in Ubuntu, and SDR# in Windows. I'm mainly interested in SW 2mhz to 30mhz broadcasts. I can pull in only a few broadcasts, including WWV on 2.5, 5, 10, and 15mhz depending on the time of day. Most of the rest are buried in interference. There's 2 AM radio stations causing a lot of bleedover from about 0mhz to 5mhz, they are KSDO-AM 1130 kHz and KCBQ-AM 1170 khz near San Diego where I am. There's also a large spike in background signals every 30khz. I'm not sure where that's from, but it could be from my longwire being parallel to power lines about 50ft away. There's no other place to put the longwire. Is there a conventional mast antenna that would work better? I was looking for a discone antenna and LMR400 cable, but most are for above 30mhz. What about a high pass filter to drown out AM radio? And what about the spike every 30khz?
Interference on SW bands
- Thread starter bswarm
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ka3jjz
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You're in a tough situation with those power lines so close to you. I'd highly recommend a Wellbrook or Pixel loop, and mount it as far away from those power lines as you can
The AM stations that are causing you overload might indicate too much gain being applied in the software. If you can't reduce the gain enough then certainly there are MW filters that you can get to knock out the entire MW band if you're really not interested in them. For example...
SWL Filters | PAR Electronics | Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts
The spike could also be caused, I think, by too much gain, but I'll let others who are more SDR knowledgeable comment on that. The spikes could also be caused by the power lines due to crappy insulators or broken insulation near the poles. And too much gain can also result in excessive noise. I would also make sure that something with the PC itself (unshielded cables are wonderful noise antennas) isn't the culprit. Mike
The AM stations that are causing you overload might indicate too much gain being applied in the software. If you can't reduce the gain enough then certainly there are MW filters that you can get to knock out the entire MW band if you're really not interested in them. For example...
SWL Filters | PAR Electronics | Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts
The spike could also be caused, I think, by too much gain, but I'll let others who are more SDR knowledgeable comment on that. The spikes could also be caused by the power lines due to crappy insulators or broken insulation near the poles. And too much gain can also result in excessive noise. I would also make sure that something with the PC itself (unshielded cables are wonderful noise antennas) isn't the culprit. Mike
I'm pretty sure I found part of the cause of the interference. My neighbors on both sides of my house have solar electric panels with DC/AC power inverters on the roof that are less than 10' from each end of my longwire. As soon as the sun sets, the spikes every 30khz goes away. I still have bleedover from nearby AM radio stations up to about 5 khz though. I'll try a loop antenna mounted as far away as possible.
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