[amsat-bb] FO-29 QRM

Zach Leffke zleffke at vt.edu
Mon Jul 25 18:17:36 UTC 2016


This is an interesting topic, and I know there has been a thread or two 
on it in the past.  FO-29 is a unique bird in that the uplink passband 
fully covers about half of the allocated satellite band at 2m.

I currently have a project (albeit shelved at the moment, but we do have 
a code base built up) going here at VT that is looking to geolocate 
these types of interferers by taking doppler measurements, specifically 
looking at FO-29.  Right now I'm exploring this as part of a potential 
class project as it teaches the basics of orbits, doppler shift, and how 
to simulate these types of things in software.  It is actually pretty 
similar to the AO-73 to FO-29 crosslink project we did for the SatCom 
class, with the signal source being an illegal transmitter on the Earth 
instead of another amateur bird.

In my initial research/experiments with this we have heard both Spanish 
and English (about a 50/50 split), and I know there have been previous 
reports of Portugese (Brazil).  Most of the time the signals tended to 
show up in the lower portion of the downlink passband during our 
experiments if I recall correctly.  Some of those recordings too were 
with South/Central America completely out of the footprint on ascending 
passes.  And I remember from previous threads folks mentioning this type 
of thing over Europe as well (I think there is even a Youtube video or a 
blog out there somewhere).  So I would say that calling this problem 
'prolific' is reasonable, and that no one country is at fault.

My question for the group is this:  Would a database of these 
interference events be something worth taking to say the IARU?  If we 
keep this project going and a few other things we are working on come 
together, it is my longer term goal is to take frequent recordings of 
these events and build up a database with records of who was 
transmitting, what language, what frequency, what mode, and what country 
(maybe even city?) they were transmitting from. After we build up a good 
data set, we could then go to the legal bodies in those countries (or 
the IARU?) and hopefully have them lean on the illegal ops to cease 
transmission or at least change frequency out of the satellite bands.

I won't hold my breath about the various bureaucracies of the world 
actually taking action against the illegal transmitters, but it couldn't 
hurt to try right?  And it would be good to at least document the 
prolific nature of the problem.  For the mean time though, its an 
interesting phenomenon and makes for a potentially good class project.


-Zach, KJ4QLP

P.S.  I'm having visions of a fleet of Amateur Radio SIGINT birds 
monitoring our spectrum.  A 200 kHz receiver for the 2m band, a 3 MHz 
receiver for the UHF band, combined together and downlinked in say 
S-band where there's more room to play.  Kind of like how the 
COSPAS-SARSAT payloads on the NOAA birds are looking for emergency 
beacons at 406 MHz and bent piping the signals down in L-Band. Probably 
not feasible...but it would be cool and useful for policing our 
spectrum, and would help defend the S-Band spectrum for hams.

Research Associate
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305

On 7/24/2016 9:34 PM, R.T.Liddy wrote:
> Question:
> If I posted this at 2:02 PM EDT, why does it take until  8:46 PM to get forwarded by the AMSAT-BB ? ? ? The formatting gets fouled-up, too, with the sentences run together.
> Just curious.....   73,     Bob  K8BL
>
>        From: R.T.Liddy <k8bl at ameritech.net>
>   To: AMSAT BB <amsat-bb at amsat.org>
>   Sent: Sunday, July 24, 2016 2:02 PM
>   Subject: Re: [amsat-bb] FO-29 QRM
>     
> Drew,
> The Spanish-speaker's Call sounds like KD4MDF after listeningto it multiple times.  Kilo-Delta-Cuatro-Mike-Delta-Fauxtrot He slurs the last letter. That listing is from Orlando, FL.  Heprobably doesn't realize that he's on a SAT uplink freq.
> The foul-mouthed Anglo guy sounds like a Trucker in motion.
> GL/73,     Bob  K8BL
>
>        From: Andrew Glasbrenner <glasbrenner at mindspring.com>
>   To: amsat-bb at amsat.org
>   Sent: Sunday, July 24, 2016 12:31 PM
>   Subject: [amsat-bb] FO-29 QRM
>    
> Just now on FO-29, I observed and recorded part of some strong FM QRM. These
> signals corresponded to an uplink of 145.900, and were from at least two
> sources, as there was a Spanish language QSO (of which I caught one US
> callsign), and a possibly non-amateur QSO in English with a northeastern
> accent and foul language. One or more of these may be originating from an
> Echolink node or similar gateway outside of the identifying station's
> control. I want to put this recording out there for anyone who might know or
> recognize the stations, and anyone that may hear something I didn't. The
> recording ends at about 16:08:15Z today.
>
>   
>
> https://www.dropbox.com/s/64571tcoj0y3o2e/FO-29%20QRM%2024JUL16%20ending%201
> 6-08-15.mp3?dl=0
>
>   
>
> 73, Drew KO4MA
>
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
> are solely those of the author, and do not reflect the official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>
>
>    
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
> are solely those of the author, and do not reflect the official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>
>
>    
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
> are solely those of the author, and do not reflect the official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb



More information about the AMSAT-BB mailing list