Unknown signal

[radionut44]

Have 2 garage door openers (Liftmaster) with 315 MHz receivers that have worked well from at least half a block away for 5 years. For past 2-3 months they have not even worked well from a foot from the door using Home Link transmitters off of car battery. Hooked up 2 different Sdr dongles today with 2 different receive software. Found very strong signal on 316.8 MHz that I suspect is desenseing the receivers. Any idea what might be the source? Problem exists at all hours and all days.

 

[a417]

turn off your main breaker for a couple of seconds, see if its in your system.

If not, then get a directional antenna and a scanner and walk looking. Could be something in your neighborhood, if you can prove it's not in your house.

 

[ecps92]

First guess is a near-by Mil/Fed instalation that just powered up a 380 TRS

Remember these are Part 15 devices per the FCC and "must accept interference"

Search 380-420 see if you have a near-by TRS

Have 2 garage door openers (Liftmaster) with 315 MHz receivers that have worked well from at least half a block away for 5 years. For past 2-3 months they have not even worked well from a foot from the door using Home Link transmitters off of car battery. Hooked up 2 different Sdr dongles today with 2 different receive software. Found very strong signal on 316.8 MHz that I suspect is desenseing the receivers. Any idea what might be the source? Problem exists at all hours and all days.

 

[BM82557]

With a freq of 316.8 a possibility is military aircraft (225 to 380 MHz). Any airports within your receiving range? The tower, approach and departure freqs all have UHF equivalents. Another possibility is ARTCC centers, Atlanta, Washington etc or a TRACON.

 

[nd5y]

Found very strong signal on 316.8 MHz that I suspect is desenseing the receivers. Any idea what might be the source? Problem exists at all hours and all days.

What does it sound like?
Is it continuous 24/7?

 

[wtp]

Problem exists at all hours and all days.
that sounds like all the time...

 

[nd5y]

Problem exists at all hours and all days.
that sounds like all the time...

OP didn't say if the 316.8 signal is there all the time, just that his problem is happening all the time.

 

[wtp]

touche.

 

[radionut44]

Signal is there all the time, so is problem.