137.9375 Mhz unknown

[PDXh0b0]

I hear this mostly on weekends(because I'm sitting around)
Set up is a qfh antenna /srd recording noaa & meteor weather satellite transmissions....
Location Woodland Wa

Sounds something like in-flight testing

Audio recording am modulation

 

[TerryPavlick]

I hear this mostly on weekends(because I'm sitting around)
Set up is a qfh antenna /srd recording noaa & meteor weather satellite transmissions....
Location Woodland Wa

Sounds something like in-flight testing

Audio recording am modulation

Sounds more like an aerobatic team practicing - they are way out of band using that frequency.

Just curious - could they be on a regular VHF airband frequency but overloading the SDR ? I have a similar issue here when monitoring my local airport unicom on 122.700 - the aircraft because they are very close by come in on 245.400 Mhz (but they are on 122.700)

 

[BruceMichaels]

I've had the same thing on my RTL-SDR, but I just put it off as the SDR is a little warm. I haven't heard of the US using anything other than .025 steps.

 

[TerryPavlick]

I've had the same thing on my RTL-SDR, but I just put it off as the SDR is a little warm. I haven't heard of the US using anything other than .025 steps.

Agree - on the temperature of the unit........may be affecting stability.

 

[PDXh0b0]

Sounds more like an aerobatic team practicing - they are way out of band using that frequency.

Just curious - could they be on a regular VHF airband frequency but overloading the SDR ? I have a similar issue here when monitoring my local airport unicom on 122.700 - the aircraft because they are very close by come in on 245.400 Mhz (but they are on 122.700)

Didn't see it with an rsp1a & jpole at 8mhz sample rate. Will make a dx mission out of this next Saturday 😀

 

[AirScan]

Sounds something like in-flight testing

I agree with Terry, to me it sounds like some sort of aerobatic/formation practice with piston type aircraft. Maybe warbird types ? Can you provide a date and approximate time you heard that recording ? We might be able to ID the aircraft by checking the ADS-B replay. My first guess would be they are using a frequency between 122.000 and 123.975 MHz ?

 

[PDXh0b0]

I agree with Terry, to me it sounds like some sort of aerobatic/formation practice with piston type aircraft. Maybe warbird types ? Can you provide a date and approximate time you heard that recording ? We might be able to ID the aircraft by checking the ADS-B replay. My first guess would be they are using a frequency between 122.000 and 123.975 MHz ?

04/19
14:10 - 14:33 PDT

 

[TerryPavlick]

04/19
14:10 - 14:33 PDT

Here is a guess but the logic of the aircraft's history makes sense

N526KP Flight Tracking and History 19-Apr-2025 (KSPB-KSPB) - FlightAware

Track N526KP flight from Scappoose to Scappoose

www.flightaware.com

and this incident report involving the same aircraft

Ground Collision: Van's RV-8, N526KP and Van's RV-8, N808LD; accident occurred July 08, 2021 at Hillsboro Airport (KHIO), Portland, Oregon

Aviation Accident Final Report - National Transportation Safety Board The National Transportation Safety Board did not travel to the sc...

www.kathrynsreport.com

note this portion of the report....

Analysis

The group of 6 airplanes were practicing formation flight for an airshow the following day. The airplanes were to takeoff in three groups of 2-airplane elements.

picture of N526KP taxing by another aircraft that is not doing so well

 

[PDXh0b0]

Here is a guess but the logic of the aircraft's history makes sense

N526KP Flight Tracking and History 19-Apr-2025 (KSPB-KSPB) - FlightAware

Track N526KP flight from Scappoose to Scappoose

www.flightaware.com

and this incident report involving the same aircraft

Ground Collision: Van's RV-8, N526KP and Van's RV-8, N808LD; accident occurred July 08, 2021 at Hillsboro Airport (KHIO), Portland, Oregon

Aviation Accident Final Report - National Transportation Safety Board The National Transportation Safety Board did not travel to the sc...

www.kathrynsreport.com

note this portion of the report....

Analysis

The group of 6 airplanes were practicing formation flight for an airshow the following day. The airplanes were to takeoff in three groups of 2-airplane elements.

picture of N526KP taxing by another aircraft that is not doing so well

View attachment 182138

Makes sense, I have several hits from that plane. When it flies over there are usually 3 of them doing maneuvers

 

[AirScan]

The website is a bit dated but maybe it's these guys ? The West Coast Ravens.

I suspect they would be using an air-air frequency in the 122.000 to 123.975 range. If anyone in the area can confirm ?

 

[TerryPavlick]

The website is a bit dated but maybe it's these guys ? The West Coast Ravens.

I suspect they would be using an air-air frequency in the 122.000 to 123.975 range. If anyone in the area can confirm ?

Well not sure how accurate AI is but anyway