Is GRAVES Radar offline?

[BiggarDigger]

Hi all,

I've not detected any meteor reflections since 07:38 on the 20th March.  I do see locally generated interference heterodyne signals in SDR# and in Spectrum Lab.  I can tune to both VHF music radio and the 2m Amateur band and detect plenty of signals.  It seems my SDR is functioning OK.

Can anyone confirm if they have received echoes from GRAVES since yesterday morning?

Richard

 

[BiggarDigger]

Hmmm...I have echoes again now.  Not many, but they are present:

 

Strange.

 

[IanL]

Like to be able to tell you but my data drive filled up two days ago and only just started getting logs and images this afternoon after clearing it up!

[BiggarDigger]

1 hour ago, IanL said:

Like to be able to tell you but my data drive filled up two days ago and only just started getting logs and images this afternoon after clearing it up!

Oops! Need a bigger drive Ian!

I still can't explain the lack of echoes during that 36 hour period.  It has been very wet here recently, but I'm fairly sure the antenna feeder stayed dry.  Water ingress would have killed the weak signals.

The presence of vhf radio and 144MHz amateur signals demonstrated the RTL-SDR was functional.

Perhaps, I'm looking at the wrong end: maybe the issue was in the SDR IF or baseband feed into Spectrum Lab.  A reduction in audio gain or a problem with IF AGC might have taken the audio below detection threshold, while a strong vhf radio signal would still be audible.

Maybe there was maintenance at the transmitter that tweaked the beam width or azimuth switching, affecting reflections received at my northern latitude?

Perhaps the cause is lost in the mists of time, but there's been plenty of echoes received over the last 24 hours, so for now, all is good again.

Richard 

[IanL]

Have taken a look at the RMOB data, it is clear there was a period of about 36 hours where GRAVES was off or doing something different. Multiple observers show zero detections during the period with detections before and after.

Normal service resumed about 18:00 yesterday (21st March).

[BiggarDigger]

Thanks Ian, that makes me feel a lot better about the detection system here.

Being a military radar, I doubt we'll ever know if it was a fault, maintenance or some other reason.

Richard