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AR15.COM
5/10/2014 8:17:53 PM EDT
On 40 meters and it sounds like someone is sweeping the band with a vfo while ftrasnmitting

I put the pan adapter on wide and I see multiples of it but they are not parallel (like concentric portions of curves)

Then they get faster and faster, the the noise floor jumps about 10 db.


Meteors????
5/10/2014 9:05:06 PM EDT
[#1]
I've seen that on the scope before.  Didn't really know how capture it.
5/10/2014 9:34:39 PM EDT
[#2]
Probably our old friend OTH Radar.
5/11/2014 5:38:42 AM EDT
[#3]
Quote History
Quoted:
Probably our old friend OTH Radar.
View Quote



Not Radar
5/11/2014 6:02:26 AM EDT
[#4]
Ionosonde which is an ionosphereic measuring device.
5/11/2014 8:28:43 AM EDT
[#5]
http://en.wikipedia.org/wiki/Ionosonde
5/11/2014 8:38:51 AM EDT
[#6]
I've heard sweepers before.  This goes up and down and stays within a particular band.

The normal sweepers I see start at the bottom of the spectrum and always work up.
5/11/2014 9:33:59 AM EDT
[#7]
This was strange because it was multiples and they were not going
at the same rate more like seeing a portion of concentric circles.

What was odd was the noise floor jumped at least 10 db
That leads me to thing something ionized the atmosphere

I have just not sen that before, coupled with the jump in the noise level

5/11/2014 9:58:43 AM EDT
[#8]
Maybe it was a strange noise source in your local area?  I've seen some very strange signals coming from electronics and such around the house and neighborhood.
5/11/2014 12:02:15 PM EDT
[#9]
Quote History
Quoted:
This was strange because it was multiples and they were not going
at the same rate more like seeing a portion of concentric circles.

What was odd was the noise floor jumped at least 10 db
That leads me to thing something ionized the atmosphere

I have just not sen that before, coupled with the jump in the noise level

View Quote


Direct sequence spread spectrum (aka CDMA) will raise the noise floor like that
(In fact, if you've got a SDR-RTL setup, look at the spectrum in the
cell bands and you'll visibly see the rise in noise floor on the CDMA
channels.

If not radar, someone was sounding before turning on a spread spectrum
transmitter. Perhaps military NVIS?