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2M Interference--US Army JLENS Project

Jan 8th 2015, 21:13

KB3WYD

Joined: Jan 16th 2012, 00:25
Total Topics: 0
Total Posts: 0
Has anyone in the Baltimore, MD. area experienced Multiple tones being generated all over the 2 Meter Band especially on Repeaters while they are transmitting at the higher end of the band. I first heard it on my External Speakers hooked up to my Kitchen TV, The TV was off and I was like WHAT THE HECK... I NEVER heard that before. What is this noise. I later went into the Mobile and heard it on 2 Meters. I then went into the house and tracked it down as best I could.

I believe that the US Army JLENS "Blimp" (technically called an Aerostat) is generating these tones around 149.400- 149.500 MHz and should be fairly strong for quite a few miles as it is tethered at 10,000 FT. I can only hear these tones when it is aloft in the air.

These tests are supposed to last for 3 years during good weather conditions. That is going to be awful for using 2 Meters around here at least.

If you would like to read more about it.....Type in JLENS in a Google search bar. There are plenty of articles about them.

Dave
KB3WYD

Feb 28th 2015, 20:39

w3bx

Joined: Apr 26th 2012, 17:25
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Total Posts: 0
Did you get any more info on this? I think I heard the same thing a few months ago and definitely heard it again today. I was listening to the Anne Arundel Radio club 147.075 repeater and the periodic tones made the repeater almost unusable. I went up to Baltimore Harbor to see the guys using the NS Savannah station, K3SAV, this morning. I had my 2m HT on the deck. The tones were very strong and the JLENS aerostat was clearly visible.

73,
Joe.
AB3PZ
Mar 1st 2015, 00:34

KB3WYD

Joined: Jan 16th 2012, 00:25
Total Topics: 0
Total Posts: 0
There were 2 frequencies I heard those tones very clearly on using a scanner.
One was 138.400 MHz and the other was 149.400 MHz.
The strange thing is they seem to be changing the frequencies from time to time as sometimes I hear the interference but cannot track down what frequency it is on exactly with the equipment I have.

Dave
KB3WYD

No other info at this time.
Mar 1st 2015, 23:17

WA9WVX

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Between the Air Force's UHF PAVE PAWS System and Army's JLENS System the Amateur Radio Community on the eastcoast are receiving some of the most restrictive interference problems to deal with.

http://venturebeat.com/2014/12/17/giant-military-blimps-set-to-defend-the-east-coast-from-attack/

Dan
WA9WVX
May 28th 2015, 10:20

N3EOD

Joined: Dec 23rd 2005, 14:03
Total Topics: 0
Total Posts: 0
I have the same issue. I work close to where the JLENS is and I have interference all the 2m repeaters I have programmed.
May 28th 2015, 10:20

N3EOD

Joined: Dec 23rd 2005, 14:03
Total Topics: 0
Total Posts: 0
I have the same issue. I work close to where the JLENS is and I have interference all the 2m repeaters I have programmed.
Jun 19th 2015, 15:43

AB3SX

Joined: Aug 22nd 2013, 00:12
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Total Posts: 0
I am curious to know the mechanism of interference ( fundamental overload, image responses, or is there really some radiated energy falling in the ham bands?).

Is this being observed by people using well-designed and constructed equipment, such as Motorola base station gear?

(In my case, inexpensive and simple-design Chinese radio gear is being rendered unusable at times, and I am about 55 miles from the Aberdeen Proving Ground, which is where the unit seems to be moored)
Aug 7th 2015, 17:14

k3dak

Joined: Sep 30th 2003, 14:04
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Total Posts: 0
I have the issue with my Motorola 2m gear, Yaesu, and Icom gear. Not counting my hackrf, rtlsdr dongles, and cheaper scanner radios.

A quick perusal of the specs of the JLENS Aerostat available via google, shows that it's able to provide up to 20kW of power to equipment in the aerostat. If even 1/2 of that is used for those frequencies, I think we can see how it's effecting our equipment.

I think it's time for us amateurs to start to reach out to businesses who have VHF licenses to suggest they complain when they have issues.
Sep 22nd 2015, 01:48

kb3zzj

Joined: Jun 6th 2013, 17:27
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Total Posts: 0
I made a post about this on my blog w/ SDR# signal screenshot and .wav capture - http://neal-anders.com/blog/archives/80940

It's also being picked up by my Uniden BC796D Scanners w/ Discone Antenna @15ft on the Air Bands ~7 miles from KBWI -- it's sometimes entertaining to listen in on incoming aircraft talk to ATC about the "blimps" and hear there (ATC's) varied explanations - lots of pilots concerned about airspace..
Oct 28th 2015, 18:15

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
http://www.cnn.com/2015/10/28/politics/loose-blimp-norad-east-coast/index.html
Right now, the blimp has broken loose from its mooring an is now flying over Pennsylvania

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