Noise "Problem" at KPH/KFS


Glenn Elmore
 

Maybe only peripherally related to this discussion but here's a link to multiple ionosondes, managed by Terry Bullet, W0ASP , for Boulder Ionosonde (listed) and NOAA.

https://www.ngdc.noaa.gov/stp/IONO/rt-iono/latest/latest.html

I believe that one is 4kW ERP pointed straight up perhaps repeated CW-like sweeps every 15 minutes, but there are many and some not listed. I get the impression that these are ill-coordinated by the FCC or anyone else, some may be academic institutions.

 

Glenn

On 2022-04-21 11:13, Phil Karn wrote:

These chirped signals are always radars of some form, most likely CODAR or similar for sea state surveillance.

Anybody know what ionosphere sounders look like? I often see chirp radar bursts all over HF, usually around the MUF, but I don't know if they're military over-the-horizon radars or civilian ionosondes.

Chirped FM is a traditional radar signal but there are many others. Most would look like high speed data or even broadband noise, most likely with a repeating structure. Any repetitive signal, no matter how complex, will consist of spectral lines spaced by the repetition interval. E.g., when HAARP was active on 6.8 and 6.9 a week ago, one of their signals consisted of spectral lines about 49 Hz apart occupying a total of maybe 50 kHz. The lines were so sharp that you could still see other signals between them despite their enormous ERP.

Phil









Phil Karn
 

These chirped signals are always radars of some form, most likely CODAR or similar for sea state surveillance.

Anybody know what ionosphere sounders look like? I often see chirp radar bursts all over HF, usually around the MUF, but I don't know if they're military over-the-horizon radars or civilian ionosondes.

Chirped FM is a traditional radar signal but there are many others. Most would look like high speed data or even broadband noise, most likely with a repeating structure. Any repetitive signal, no matter how complex, will consist of spectral lines spaced by the repetition interval. E.g., when HAARP was active on 6.8 and 6.9 a week ago, one of their signals consisted of spectral lines about 49 Hz apart occupying a total of maybe 50 kHz. The lines were so sharp that you could still see other signals between them despite their enormous ERP.

Phil


Jim Lill
 

more wave radar stuff....  CODAR like?

On 4/21/22 10:51, ON5KQ wrote:
I could not see the problem at kph today, but instead there was a similar signal about 20db weaker that yesterday observed at kfs at local morning time:



Obviously a 'real' signal, perhaps related to military. locally at the pacific coast in front of kfs ?!?
Yesterday the signal was much stronger and lower in frequency, reaching  -30dbm at kph...

Ulli, ON5KQ


ON5KQ
 

I could not see the problem at kph today, but instead there was a similar signal about 20db weaker that yesterday observed at kfs at local morning time:



Obviously a 'real' signal, perhaps related to military. locally at the pacific coast in front of kfs ?!?
Yesterday the signal was much stronger and lower in frequency, reaching  -30dbm at kph...

Ulli, ON5KQ