Source
r/amateurradio•
devjustinian

Strong RFI across the 70cm band, every 30 seconds?

I finally put up an antenna on my apartment porch to use with a mobile dual-band radio, and I hear a very loud buzz exactly every 30 seconds. It's much stronger than local repeater traffic, and I hear it all across the 70cm band. Up until now I've been mostly using a HT when walking to work, and have not heard this interference, though if I take the HT out next to my porch antenna it does pick it up as well.

I'm a pretty new ham, so maybe this is old hat to you guys, but do you have any thoughts on what this interference might be, or if I can filter it out?

Posted Mar 12, 2018, 5:41 AM UTC

107
Mrucux7•

I'd say a weather monitoring station (the ones that also function as clocks), those are often within 70cm, and if you're close enough to the transmitter, they can overload stuff easily.

5
MakinRFN3*** [T]•

I have an Accurite weather station and can confirm it splashes 440 when the sensors transmit.

1
progressivejpeg[Extra@CA,USA]•

If possible try turning off power at your breaker box and see if the signal goes away. That would at least give an indication of whether the source is local. However this implies having a way to power your radio while the power is off.

3
bigterryCN85 [G]•

i second this. i had weird noise on mine too, even when hooked to the outdoor antenna. thought it might be the computer but nope, powered down and unplugged, still had it.

turned out it was interference from my roommates laptop about 25 feet away. my pc was completely powered off, but he was sitting at the counter with his laptop, and thats what it ended up being. once he turned his laptop off, all was good.

3
[deleted]•

[deleted]

2
PhotoJim99VE5EV (or VE5EIS) (B+) DO70•

Baofeng handheld you're using? They're very easily overwhelmed by signals on frequencies far from where you're hearing noise, if the signal is strong enough.

2
TheReallyHappySockKL5L [Extra]•

radar sweep?

0
drmpegW6RZ•

Very well could be. When I was active on 432 MHz SSB, I used to hear shipboard radar all the time here in Silicon Valley. As soon as the fog rolled in off the coast, they'd fire those radars up.

On SSB, it sounded a lot like a buzzing bee flying by as the radar swept. Oddly enough, the regular noise blanker would take it out quite well.

1