Folks,
In the San Francisco Bay Area it looks like most of the 440 MHZ FM repeaters will have to be shut down to avoid interference with the PAVE PAWS radar site at Beale Air Force Base in Marysville. That got me thinking that I might be able to detect the radar from my house even though it is almost 200 miles away and masked by terrain. Sure enough, I think I can. I've captured data and audio and posted it on my web and on EaglePedia.
Click HERE http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm to read my log and listen to the audio.
73,
Juan - WA6HTP
Juan,
Great recording.
By chance, did you have the Noise Blanker enabled on your Kenwood rig when recording? It sounds like it might have been, with an increase in mute after each pop...
Dave
On 9/3/07, Juan Rivera juan-rivera@sbcglobal.net wrote:
Folks,
In the San Francisco Bay Area it looks like most of the 440 MHZ FM repeaters will have to be shut down to avoid interference with the PAVE PAWS radar site at Beale Air Force Base in Marysville. That got me thinking that I might be able to detect the radar from my house even though it is almost 200 miles away and masked by terrain. Sure enough, I think I can. I've captured data and audio and posted it on my web and on EaglePedia.
Click HERE to read my log and listen to the audio.
73,
Juan - WA6HTP
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise blanker. I'll take a look and try again if it was on. Right now I can't communicate with the CAN-Do module or I would switch to the 70 cm prototype receiver and repeat the test.
Juan
-----Original Message----- From: Dave hartzell [mailto:hartzell@gmail.com] Sent: Monday, September 03, 2007 9:17 AM To: juan-rivera@sbcglobal.net Cc: eagle@amsat.org; Bill Ress; Dave Black (Home); Dave Black (Work); David Smith; Don Ferguson; Juan.Rivera (Work); Samsonoff@Mac. Com Subject: Re: PAVE PAWS EMI
Juan,
Great recording.
By chance, did you have the Noise Blanker enabled on your Kenwood rig when recording? It sounds like it might have been, with an increase in mute after each pop...
Dave
On 9/3/07, Juan Rivera juan-rivera@sbcglobal.net wrote:
Folks,
In the San Francisco Bay Area it looks like most of the 440 MHZ FM
repeaters
will have to be shut down to avoid interference with the PAVE PAWS radar site at Beale Air Force Base in Marysville. That got me thinking that I might be able to detect the radar from my house even though it is almost
200
miles away and masked by terrain. Sure enough, I think I can. I've captured data and audio and posted it on my web and on EaglePedia.
Click HERE to read my log and listen to the audio.
73,
Juan - WA6HTP
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise blanker. I'll take a look and try again if it was on. Right now I can't communicate with the CAN-Do module or I would switch to the 70 cm prototype receiver and repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
Attached is a Matlab plot of Juan's SDR-IQ PAVE PAWS capture...
In the plot, you can really see the noise-blanker suppression after each spike...
Dave
On 9/3/07, Robert McGwier rwmcgwier@gmail.com wrote:
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise blanker. I'll take a look and try again if it was on. Right now I can't communicate with the CAN-Do module or I would switch to the 70 cm prototype receiver and repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
-- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson
Dave,
The noise blanker is off and when you think about it, it doesn't matter anyway since I'm pulling the 10.7 MHz 3rd IF out of the TS-2000. The noise blanker is implemented in DSP farther downstream. I'm not sure what is causing that. I'll have to scratch my head some more...
Juan
-----Original Message----- From: Dave hartzell [mailto:hartzell@gmail.com] Sent: Monday, September 03, 2007 10:58 AM To: Robert McGwier Cc: juan-rivera@sbcglobal.net; David Smith; Dave Black (Work); Dave Black (Home); eagle@amsat.org; Samsonoff@Mac. Com; Juan.Rivera (Work) Subject: Re: [eagle] Re: PAVE PAWS EMI
Attached is a Matlab plot of Juan's SDR-IQ PAVE PAWS capture...
In the plot, you can really see the noise-blanker suppression after each spike...
Dave
On 9/3/07, Robert McGwier rwmcgwier@gmail.com wrote:
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
-- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson
This reminds me of a briefing we got at work from a UHF receiver vendor regarding their receiver's susceptibility to radar. In it they demonstrated how a strong enough RF pulse would actually cause a bias shift on the first stage resulting in a 'blanking effect' until the RF induced voltage decayed off. Perhaps we're seeing something similar here?
73, Lee-KU4OS
On Monday 03 September 2007 14:32:05 Juan Rivera wrote:
Dave,
The noise blanker is off and when you think about it, it doesn't matter anyway since I'm pulling the 10.7 MHz 3rd IF out of the TS-2000. The noise blanker is implemented in DSP farther downstream. I'm not sure what is causing that. I'll have to scratch my head some more...
Juan
-----Original Message----- From: Dave hartzell [mailto:hartzell@gmail.com] Sent: Monday, September 03, 2007 10:58 AM To: Robert McGwier Cc: juan-rivera@sbcglobal.net; David Smith; Dave Black (Work); Dave Black (Home); eagle@amsat.org; Samsonoff@Mac. Com; Juan.Rivera (Work) Subject: Re: [eagle] Re: PAVE PAWS EMI
Attached is a Matlab plot of Juan's SDR-IQ PAVE PAWS capture...
In the plot, you can really see the noise-blanker suppression after each spike...
Dave
On 9/3/07, Robert McGwier rwmcgwier@gmail.com wrote:
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
-- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Lee,
That's possible. In a few weeks we'll gather up our equipment and head for the top of a local mountain where we'll have a much better shot at the PAVE PAWS site. Right now we're not completely sure we're really looking at PAVE PAWS. It may be that our data from old environmental impact statements is obsolete. We know something has changed or the Department of Defense wouldn't be clearing out all the local ham repeaters.
Juan - WA6HTP
-----Original Message----- From: Lee McLamb [mailto:ku4os@cfl.rr.com] Sent: Monday, September 03, 2007 4:43 PM To: eagle@amsat.org; juan-rivera@sbcglobal.net Cc: 'Dave hartzell'; 'Robert McGwier'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
This reminds me of a briefing we got at work from a UHF receiver vendor regarding their receiver's susceptibility to radar. In it they demonstrated
how a strong enough RF pulse would actually cause a bias shift on the first stage resulting in a 'blanking effect' until the RF induced voltage decayed off. Perhaps we're seeing something similar here?
73, Lee-KU4OS
On Monday 03 September 2007 14:32:05 Juan Rivera wrote:
Dave,
The noise blanker is off and when you think about it, it doesn't matter anyway since I'm pulling the 10.7 MHz 3rd IF out of the TS-2000. The
noise
blanker is implemented in DSP farther downstream. I'm not sure what is causing that. I'll have to scratch my head some more...
Juan
-----Original Message----- From: Dave hartzell [mailto:hartzell@gmail.com] Sent: Monday, September 03, 2007 10:58 AM To: Robert McGwier Cc: juan-rivera@sbcglobal.net; David Smith; Dave Black (Work); Dave Black (Home); eagle@amsat.org; Samsonoff@Mac. Com; Juan.Rivera (Work) Subject: Re: [eagle] Re: PAVE PAWS EMI
Attached is a Matlab plot of Juan's SDR-IQ PAVE PAWS capture...
In the plot, you can really see the noise-blanker suppression after each spike...
Dave
On 9/3/07, Robert McGwier rwmcgwier@gmail.com wrote:
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
-- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "If you're going to be crazy, you have to get paid for it or else you're going to be locked up." Hunter S. Thompson
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Bob,
We spent the afternoon trying to characterize the pulses that I see here with my antenna pointed north. See my last plot for details:
http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm
You'll see several evenly spaced areas showing many hits over about a 30 minute span. They are too evenly spaced to be random but they don't conform to the PAVE PAWS band plan that I pulled from environmental impact reports from years ago. Because of the recent push to clear ham repeaters off of the air anywhere in the vicinity of a PAVE PAWS site, we know something has changed, but what?
To resolve all of our questions we'll need to move to an unobstructed location atop a local mountain and try again. That will take a few weeks. Until then I would be cautious about using my .wav file. It might be the neighbor driving around the block on his Harley.
73, Juan
-----Original Message----- From: Robert McGwier [mailto:rwmcgwier@gmail.com] Sent: Monday, September 03, 2007 10:11 AM To: juan-rivera@sbcglobal.net Cc: 'Dave hartzell'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; eagle@amsat.org; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
Hee Hee. Well Harley pulses can be a good noise source to remove as well!
Bob
Juan Rivera wrote:
Bob,
We spent the afternoon trying to characterize the pulses that I see here with my antenna pointed north. See my last plot for details:
http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm
You'll see several evenly spaced areas showing many hits over about a 30 minute span. They are too evenly spaced to be random but they don't conform to the PAVE PAWS band plan that I pulled from environmental impact reports from years ago. Because of the recent push to clear ham repeaters off of the air anywhere in the vicinity of a PAVE PAWS site, we know something has changed, but what?
To resolve all of our questions we'll need to move to an unobstructed location atop a local mountain and try again. That will take a few weeks. Until then I would be cautious about using my .wav file. It might be the neighbor driving around the block on his Harley.
73, Juan
Another source you could be seeing is the airborne AN/APS-145 UHF radar although it typically has a fairly distinctive 6 second pattern looking in the time domain due to the antenna rotation rate.
The web site cited in the ATP has been taken down. Did you save the original files? I know there was an upgrade done at Beal so it is now known as having both the original EWR and the UEWR modes. I'm wondering if perhaps the frequencies in Table D-2 are for the EWR. Also with the 1 MHz chirp, "channel 11" will be creeping into the satellite sub-band as well.
Another thought that comes to mind is that we might be well served to try to pick our uplink passband in the guard bands if we can determine what they are. AO-40's 70cm analog uplink was 435.550 - 435.800 MHz. That gave it an almost perfect worst case frequency alignment with channel 13. We'd probably need to check all three sites, Beale, Cape Cod and perhaps Flyindales, UK to feel sure we had a good handle on the spectrum. Another advantage to putting ourselves in the 'quiet zones' is that our Users might avoid some of the problems the repeater owners are now having higher in the band. ARRL is reporting that some repeaters are being asked to reduce their output by 7 to 54 dB.
73, Lee-KU4OS
On Monday 03 September 2007 21:47:00 Juan Rivera wrote:
Bob,
We spent the afternoon trying to characterize the pulses that I see here with my antenna pointed north. See my last plot for details:
http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm
You'll see several evenly spaced areas showing many hits over about a 30 minute span. They are too evenly spaced to be random but they don't conform to the PAVE PAWS band plan that I pulled from environmental impact reports from years ago. Because of the recent push to clear ham repeaters off of the air anywhere in the vicinity of a PAVE PAWS site, we know something has changed, but what?
To resolve all of our questions we'll need to move to an unobstructed location atop a local mountain and try again. That will take a few weeks. Until then I would be cautious about using my .wav file. It might be the neighbor driving around the block on his Harley.
73, Juan
-----Original Message----- From: Robert McGwier [mailto:rwmcgwier@gmail.com] Sent: Monday, September 03, 2007 10:11 AM To: juan-rivera@sbcglobal.net Cc: 'Dave hartzell'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; eagle@amsat.org; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
Lee,
I think you may be correct - my data may in obsolete. I think we will be able to determine if what I am seeing here is really PAVE PAWS by moving to a mountain top that has line of sight to them, or moving into the local area near the base. I am going to try to make a stereo .wav file with my main receiver on one channel and the sub receiver on the other. By tuning the two receivers to what appears to be two different PAVE PAWS channels I may be able to see if the pops I hear are correlated across both or not. If they are not I think that strengthens my feeling that this probably is PAVE PAWS. Once we get up on a mountain we can tell with much more confidence, but I can try this now.
I may have the original files, but I extracted everything that I thought was pertinent and put it in the ATP already.
Once we get the CAN-Do module running again, and we see if there are guard bands, then I can tune the 70 cm receiver into one to see if that improves the situation.
I'll post my .wav file if I get it done this evening...
73,
Juan
-----Original Message----- From: Lee McLamb [mailto:ku4os@cfl.rr.com] Sent: Tuesday, September 04, 2007 7:38 PM To: eagle@amsat.org; juan-rivera@sbcglobal.net Cc: 'Robert McGwier'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Another source you could be seeing is the airborne AN/APS-145 UHF radar although it typically has a fairly distinctive 6 second pattern looking in the time domain due to the antenna rotation rate.
The web site cited in the ATP has been taken down. Did you save the original files? I know there was an upgrade done at Beal so it is now known as having both the original EWR and the UEWR modes. I'm wondering if perhaps the frequencies in Table D-2 are for the EWR. Also with the 1 MHz chirp, "channel 11" will be creeping into the satellite sub-band as well.
Another thought that comes to mind is that we might be well served to try to
pick our uplink passband in the guard bands if we can determine what they are. AO-40's 70cm analog uplink was 435.550 - 435.800 MHz. That gave it an
almost perfect worst case frequency alignment with channel 13. We'd probably need to check all three sites, Beale, Cape Cod and perhaps Flyindales, UK to feel sure we had a good handle on the spectrum. Another advantage to putting ourselves in the 'quiet zones' is that our Users might avoid some of the problems the repeater owners are now having higher in the band. ARRL is reporting that some repeaters are being asked to reduce their
output by 7 to 54 dB.
73, Lee-KU4OS
On Monday 03 September 2007 21:47:00 Juan Rivera wrote:
Bob,
We spent the afternoon trying to characterize the pulses that I see here with my antenna pointed north. See my last plot for details:
http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm
You'll see several evenly spaced areas showing many hits over about a 30 minute span. They are too evenly spaced to be random but they don't conform to the PAVE PAWS band plan that I pulled from environmental impact reports from years ago. Because of the recent push to clear ham repeaters off of the air anywhere in the vicinity of a PAVE PAWS site, we know something has changed, but what?
To resolve all of our questions we'll need to move to an unobstructed location atop a local mountain and try again. That will take a few weeks. Until then I would be cautious about using my .wav file. It might be the neighbor driving around the block on his Harley.
73, Juan
-----Original Message----- From: Robert McGwier [mailto:rwmcgwier@gmail.com] Sent: Monday, September 03, 2007 10:11 AM To: juan-rivera@sbcglobal.net Cc: 'Dave hartzell'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; eagle@amsat.org; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
Hi Juan,
The spectrum that you posted didn't look like the radar interference that I would see on 70 cm in Los Angeles when the Navy conducted exercises off the coast. It looked like dozens of emitters, each sweeping more or less synchronously across a few MHz, since the sweep speed on the spectrum analyzer was much lower than the repitition frequency of the radar.
73,
John KD6OZH
----- Original Message ----- From: "Juan Rivera" juan-rivera@sbcglobal.net To: "'Lee McLamb'" ku4os@cfl.rr.com; eagle@amsat.org Cc: "'David Smith'" w6te@msn.com; "'Dave Black (Work)'" dblack@mail.arc.nasa.gov; "'Dave Black (Home)'" dblack1054@yahoo.com; "'Samsonoff@Mac. Com'" samsonoff@mac.com; "'Juan.Rivera (Work)'" Juan.Rivera@gd-ais.com Sent: Wednesday, September 05, 2007 02:55 UTC Subject: [eagle] Re: PAVE PAWS EMI
Lee,
I think you may be correct - my data may in obsolete. I think we will be able to determine if what I am seeing here is really PAVE PAWS by moving to a mountain top that has line of sight to them, or moving into the local area near the base. I am going to try to make a stereo .wav file with my main receiver on one channel and the sub receiver on the other. By tuning the two receivers to what appears to be two different PAVE PAWS channels I may be able to see if the pops I hear are correlated across both or not. If they are not I think that strengthens my feeling that this probably is PAVE PAWS. Once we get up on a mountain we can tell with much more confidence, but I can try this now.
I may have the original files, but I extracted everything that I thought was pertinent and put it in the ATP already.
Once we get the CAN-Do module running again, and we see if there are guard bands, then I can tune the 70 cm receiver into one to see if that improves the situation.
I'll post my .wav file if I get it done this evening...
73,
Juan
-----Original Message----- From: Lee McLamb [mailto:ku4os@cfl.rr.com] Sent: Tuesday, September 04, 2007 7:38 PM To: eagle@amsat.org; juan-rivera@sbcglobal.net Cc: 'Robert McGwier'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Another source you could be seeing is the airborne AN/APS-145 UHF radar although it typically has a fairly distinctive 6 second pattern looking in the time domain due to the antenna rotation rate.
The web site cited in the ATP has been taken down. Did you save the original files? I know there was an upgrade done at Beal so it is now known as having both the original EWR and the UEWR modes. I'm wondering if perhaps the frequencies in Table D-2 are for the EWR. Also with the 1 MHz chirp, "channel 11" will be creeping into the satellite sub-band as well.
Another thought that comes to mind is that we might be well served to try to
pick our uplink passband in the guard bands if we can determine what they are. AO-40's 70cm analog uplink was 435.550 - 435.800 MHz. That gave it an
almost perfect worst case frequency alignment with channel 13. We'd probably need to check all three sites, Beale, Cape Cod and perhaps Flyindales, UK to feel sure we had a good handle on the spectrum. Another advantage to putting ourselves in the 'quiet zones' is that our Users might avoid some of the problems the repeater owners are now having higher in the band. ARRL is reporting that some repeaters are being asked to reduce their
output by 7 to 54 dB.
73, Lee-KU4OS
On Monday 03 September 2007 21:47:00 Juan Rivera wrote:
Bob,
We spent the afternoon trying to characterize the pulses that I see here with my antenna pointed north. See my last plot for details:
http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm
You'll see several evenly spaced areas showing many hits over about a 30 minute span. They are too evenly spaced to be random but they don't conform to the PAVE PAWS band plan that I pulled from environmental impact reports from years ago. Because of the recent push to clear ham repeaters off of the air anywhere in the vicinity of a PAVE PAWS site, we know something has changed, but what?
To resolve all of our questions we'll need to move to an unobstructed location atop a local mountain and try again. That will take a few weeks. Until then I would be cautious about using my .wav file. It might be the neighbor driving around the block on his Harley.
73, Juan
-----Original Message----- From: Robert McGwier [mailto:rwmcgwier@gmail.com] Sent: Monday, September 03, 2007 10:11 AM To: juan-rivera@sbcglobal.net Cc: 'Dave hartzell'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; eagle@amsat.org; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Hi John,
Whatever it is that we're seeing here, it's not an artifact of the spectrum analyzer since we see the same thing using the USRP DSP board.
I had what I thought was a brilliant idea -- since the TS-2000 has two receivers (a main one and a sub-receiver) I could put them in different PAVE PAWS channels and record stereo. I did and sure enough the pulses don't correlate at all. Then I moved the two receivers to opposite ends of the same channel (or at least what looks like a channel) and they still didn't correlate, or maybe they do and I'm not used to the freeware I just downloaded... Finally I put them both on the exact same frequency. They still look different. I think some if this can be explained by the fact that they are completely different designs - one is complex and the other is simple. They both have DSP processing so there could be different delays through both. Net result - I still don't know what I'm looking at. I tried to upload all of this to my web so everyone could take a look but the files are so big I have to scale everything down and try again tomorrow.
73,
Juan
-----Original Message----- From: John B. Stephensen [mailto:kd6ozh@comcast.net] Sent: Tuesday, September 04, 2007 9:55 PM To: juan-rivera@sbcglobal.net; 'Lee McLamb'; eagle@amsat.org Cc: 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Hi Juan,
The spectrum that you posted didn't look like the radar interference that I would see on 70 cm in Los Angeles when the Navy conducted exercises off the coast. It looked like dozens of emitters, each sweeping more or less synchronously across a few MHz, since the sweep speed on the spectrum analyzer was much lower than the repitition frequency of the radar.
73,
John KD6OZH
----- Original Message ----- From: "Juan Rivera" juan-rivera@sbcglobal.net To: "'Lee McLamb'" ku4os@cfl.rr.com; eagle@amsat.org Cc: "'David Smith'" w6te@msn.com; "'Dave Black (Work)'" dblack@mail.arc.nasa.gov; "'Dave Black (Home)'" dblack1054@yahoo.com; "'Samsonoff@Mac. Com'" samsonoff@mac.com; "'Juan.Rivera (Work)'" Juan.Rivera@gd-ais.com Sent: Wednesday, September 05, 2007 02:55 UTC Subject: [eagle] Re: PAVE PAWS EMI
Lee,
I think you may be correct - my data may in obsolete. I think we will be able to determine if what I am seeing here is really PAVE PAWS by moving to a mountain top that has line of sight to them, or moving into the local area near the base. I am going to try to make a stereo .wav file with my main receiver on one channel and the sub receiver on the other. By tuning the two receivers to what appears to be two different PAVE PAWS channels I may be able to see if the pops I hear are correlated across both or not. If they are not I think that strengthens my feeling that this probably is PAVE PAWS. Once we get up on a mountain we can tell with much more confidence, but I can try this now.
I may have the original files, but I extracted everything that I thought was pertinent and put it in the ATP already.
Once we get the CAN-Do module running again, and we see if there are guard bands, then I can tune the 70 cm receiver into one to see if that improves the situation.
I'll post my .wav file if I get it done this evening...
73,
Juan
-----Original Message----- From: Lee McLamb [mailto:ku4os@cfl.rr.com] Sent: Tuesday, September 04, 2007 7:38 PM To: eagle@amsat.org; juan-rivera@sbcglobal.net Cc: 'Robert McGwier'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Another source you could be seeing is the airborne AN/APS-145 UHF radar although it typically has a fairly distinctive 6 second pattern looking in the time domain due to the antenna rotation rate.
The web site cited in the ATP has been taken down. Did you save the original files? I know there was an upgrade done at Beal so it is now known as having both the original EWR and the UEWR modes. I'm wondering if perhaps the frequencies in Table D-2 are for the EWR. Also with the 1 MHz chirp, "channel 11" will be creeping into the satellite sub-band as well.
Another thought that comes to mind is that we might be well served to try to
pick our uplink passband in the guard bands if we can determine what they are. AO-40's 70cm analog uplink was 435.550 - 435.800 MHz. That gave it an
almost perfect worst case frequency alignment with channel 13. We'd probably need to check all three sites, Beale, Cape Cod and perhaps Flyindales, UK to feel sure we had a good handle on the spectrum. Another advantage to putting ourselves in the 'quiet zones' is that our Users might avoid some of the problems the repeater owners are now having higher in the band. ARRL is reporting that some repeaters are being asked to reduce their
output by 7 to 54 dB.
73, Lee-KU4OS
On Monday 03 September 2007 21:47:00 Juan Rivera wrote:
Bob,
We spent the afternoon trying to characterize the pulses that I see here with my antenna pointed north. See my last plot for details:
http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm
You'll see several evenly spaced areas showing many hits over about a 30 minute span. They are too evenly spaced to be random but they don't conform to the PAVE PAWS band plan that I pulled from environmental impact reports from years ago. Because of the recent push to clear ham repeaters off of the air anywhere in the vicinity of a PAVE PAWS site, we know something has changed, but what?
To resolve all of our questions we'll need to move to an unobstructed location atop a local mountain and try again. That will take a few weeks. Until then I would be cautious about using my .wav file. It might be the neighbor driving around the block on his Harley.
73, Juan
-----Original Message----- From: Robert McGwier [mailto:rwmcgwier@gmail.com] Sent: Monday, September 03, 2007 10:11 AM To: juan-rivera@sbcglobal.net Cc: 'Dave hartzell'; 'David Smith'; 'Dave Black (Work)'; 'Dave Black (Home)'; eagle@amsat.org; 'Samsonoff@Mac. Com'; 'Juan.Rivera (Work)' Subject: Re: [eagle] Re: PAVE PAWS EMI
Juan Rivera wrote:
Hi Dave,
I noticed that too. I killed the AGC but didn't think of the noise
blanker.
I'll take a look and try again if it was on. Right now I can't
communicate
with the CAN-Do module or I would switch to the 70 cm prototype receiver
and
repeat the test.
Juan
Yes, please. I have some interesting noise blanker stuff I want to work on to eliminate PAVE PAWS pulses on board the SDX transponder. This is the PERFECT set of signal collection (SDR-IQ of IF) for doing that work.
Thank you very much once again Juan for your extremely valuable contributions and your unbridled enthusiasm. It is very welcome indeed.
Bob
Via the Eagle mailing list courtesy of AMSAT-NA Eagle@amsat.org http://amsat.org/mailman/listinfo/eagle
Juan Rivera wrote:
Folks,
In the San Francisco Bay Area it looks like most of the 440 MHZ FM repeaters will have to be shut down to avoid interference with the PAVE PAWS radar site at Beale Air Force Base in Marysville. That got me thinking that I might be able to detect the radar from my house even though it is almost 200 miles away and masked by terrain. Sure enough, I think I can. I've captured data and audio and posted it on my web and on EaglePedia.
Click HERE http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm to read my log and listen to the audio.
Juan,
I live in Mountain View, about 125 miles from the base. If you would like, we could get together to try to record the radar with some USRP equipment, which will allow 8 or 16 MHz of RF bandwidth. This would allow us to get detailed pulse profiles and other statistics on the signal.
Matt
Matt,
That would be great. I'm free today, week day evenings, and then Friday through Sunday next week. What works best for you?
Juan
-----Original Message----- From: Matt Ettus [mailto:matt@ettus.com] Sent: Monday, September 03, 2007 10:59 AM To: juan-rivera@sbcglobal.net Cc: eagle@amsat.org; David Smith; Dave Black (Work); Dave Black (Home); Samsonoff@Mac. Com; Juan.Rivera (Work) Subject: Re: [eagle] PAVE PAWS EMI
Juan Rivera wrote:
Folks,
In the San Francisco Bay Area it looks like most of the 440 MHZ FM repeaters will have to be shut down to avoid interference with the PAVE PAWS radar site at Beale Air Force Base in Marysville. That got me thinking that I might be able to detect the radar from my house even though it is almost 200 miles away and masked by terrain. Sure enough, I think I can. I've captured data and audio and posted it on my web and on EaglePedia.
Click HERE http://www.juanr.com/pages/hobbies/ham_radio/Eagle/PAVE_PAWS.htm to read my log and listen to the audio.
Juan,
I live in Mountain View, about 125 miles from the base. If you would like, we could get together to try to record the radar with some USRP equipment, which will allow 8 or 16 MHz of RF bandwidth. This would allow us to get detailed pulse profiles and other statistics on the signal.
Matt
participants (6)
-
Dave hartzell -
John B. Stephensen -
Juan Rivera -
Lee McLamb -
Matt Ettus -
Robert McGwier