243.0MHz

[crazy_19]

For a long while (more than six months) here I have been receiving tones on 243.0. Some days they are louder/strong than others. I Dont have the slightest clue as to there source if it was a ELT the battries would be long dead and as I can receive them on my desktop scanner as well as hand-held I wouldnt think it to be mains/ground source.

Today I made a recording of it thought to post it here. In the spetrogram you clearly see the frequecy alternateing.(near both top in red and bottom in white)

wav file: https://skydrive.live.com/redir?resid=5F013380159E2C73!962

 

[kma371]

That's definitely not an ELT you're hearing.

 

[nd5y]

I have heard something similar. It was either some consumer electronics device radiating or possibly leaking from the cable TV system. ELTs don't sound anything like that.

 

[902]

I've been known to hunt an ELT or dozen and actually find them on occasion. What you're hearing is not an ELT. They sound like this (even the ones on 243 MHz): MGSC ATCM 1201 Unit 7 Audio 1 ELT Example - YouTube It's made to be unmistakable. You're hearing some sort of "unintentional emitter." Add to the list of "it might be" devices - switching power supply, someone's LAN, a birdie in the receiver, a CFL lightbulb, and the list goes on. It sounds like "junk." Welcome to our new interference-based spectrum landscape. If it's any consolation, it probably can't be heard in a plane.

 

[Avery93]

Do you or a close by neighbor have DirecTV, by chance? One of my standard (non-DVR) DirecTV receivers causes almost identical interference on both 121.5 and 243.0. The main culprit seems to be a fairly strong carrier being emitted around 486 MHz, of which both 243.0 and 121.5 are harmonics.

 

[crazy_19]

Do you or a close by neighbor have DirecTV, by chance? One of my standard (non-DVR) DirecTV receivers causes almost identical interference on both 121.5 and 243.0. The main culprit seems to be a fairly strong carrier being emitted around 486 MHz, of which both 243.0 and 121.5 are harmonics.

Indeed a few nearby houses do have dishes.!