Radio Noises in the Gulf Region on 121.50
Thread Starter
Join Date: Nov 1999
Location: "como todo buen piloto... mujeriego y borracho"
Posts: 2,005
Likes: 0
Received 0 Likes
on
0 Posts
Radio Noises in the Gulf Region on 121.50
I was just reading the post Bleeps on VHF in France which got me wondering about the strange radio noises that are pretty much constant on 121.50 MHz throughout the Gulf Region. At first I thought it was a radio problem the aircraft I was flying, but it seems to be constant on all aircraft, same sound, (and only on 121.50 MHz). Anybody know the origin of it?
Seems to be a flight safety concern, since the tendancy is to turn the volume of 121.50 down so that the noise is not so annoying (almost but not quite as bad as listening to HF), despite the operation need to monitor it, lest you get one of these transmissions:
“attention unidentified aircraft at position N27° en E051° squawking 3726, groundspeed 300 knots altitude 5000 ft. You are approaching a United States Naval Warship operating in International waters. . . . . . ”
Seems to be a flight safety concern, since the tendancy is to turn the volume of 121.50 down so that the noise is not so annoying (almost but not quite as bad as listening to HF), despite the operation need to monitor it, lest you get one of these transmissions:
“attention unidentified aircraft at position N27° en E051° squawking 3726, groundspeed 300 knots altitude 5000 ft. You are approaching a United States Naval Warship operating in International waters. . . . . . ”
Join Date: May 2005
Location: Go to the second sand dune, then turn right.
Posts: 103
Likes: 0
Received 0 Likes
on
0 Posts
is that what ausies say when they here “attention unidentified aircraft at position N27° en E051° squawking 3726, groundspeed 300 knots altitude 5000 ft. You are approaching a United States Naval Warship operating in International waters. . . . . . ” ?
Join Date: Jul 2004
Location: North of 0
Posts: 197
Likes: 0
Received 0 Likes
on
0 Posts
I have often wondered the same thing. My theory is that there is some "spillover" jamming on this frequency from military presence in the region. Warships and military aircraft all have electronic warfare equipment that can jam almost any frequency spectrum. I'm guessing that they are to be blamed although I cant substantiate my theory.
Join Date: Jun 2001
Posts: 1,451
Likes: 0
Received 0 Likes
on
0 Posts
Someone (I can't rmember who) told me years ago that it was something to do with the US military.
I agree it's a pain, making it almost impossible to listen out on 121.5 when in the Gulf area, and I also agree that this has grave safety implications should, one day, you happen to be the target being painted when a US warship makes 'that' speech we've all heard more than once.
I believe a Gulf Air A320 went within 30 seconds of going the same way as the Iranian A300 out of Bandar Abas when they approached a US Navy ship one day and neither pilot was listening out on 121.5.
I agree it's a pain, making it almost impossible to listen out on 121.5 when in the Gulf area, and I also agree that this has grave safety implications should, one day, you happen to be the target being painted when a US warship makes 'that' speech we've all heard more than once.
I believe a Gulf Air A320 went within 30 seconds of going the same way as the Iranian A300 out of Bandar Abas when they approached a US Navy ship one day and neither pilot was listening out on 121.5.
Join Date: Feb 2002
Location: BRFC, Dilmun Club, Riffa Golf Course
Posts: 66
Received 0 Likes
on
0 Posts
It could also be freq harmonics. I doubt it's got anything to do with jamming. The real problem is that there is no real regulatory authority to complain to and investigate it. The GCC Frequency Board are a joke, literally. I can't name the times we have asked them to look at something and their response is "please tell us what we should be looking for" or better yet the age old blame game, "it's the Americans".
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
The US Navy in the Gulf has a special interest in 121.5 being kept as it should be, quiet. They've got the airborne kit to pin down the source of any interference. Fixing it may be another problem, but you have to start somewhere. I'd say this is serious enough to warrant a call to your local US Navy Attache and explain the implications. I doubt very much it's the Navy causing the problem.
If any 'fix' does present an issue then the Navy also has a long range ability to switch things off.
If any 'fix' does present an issue then the Navy also has a long range ability to switch things off.
Join Date: Jan 2000
Location: Australia
Posts: 543
Likes: 0
Received 0 Likes
on
0 Posts
The Americans have nothing to do with 121.50.
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes
on
0 Posts
and what bout elvis?
Legends die hard.
Join Date: Jan 2001
Location: Anywhere I want
Posts: 327
Likes: 0
Received 0 Likes
on
0 Posts
I know the old Leander Class Frigates that the Uk and NZ had (AKA Warship 1970's tv show) couldnt use the big lattice work radar within 10nm of shore due to TV interference.
Join Date: Feb 2006
Location: Here & There
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
Iterference
I have noticed that if you have any frequency close enough to 121.5 would interfere with the transmission!
e.g: 121.10 OTBD
plus there are ample other frequencies within the area of operation,
for instance the OKBK GRD! You guys operate within the region, so figure it out.
Its a concern but I guess its just close proximity of the digits. ain't it. MATES.
INV
e.g: 121.10 OTBD
plus there are ample other frequencies within the area of operation,
for instance the OKBK GRD! You guys operate within the region, so figure it out.
Its a concern but I guess its just close proximity of the digits. ain't it. MATES.
INV
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
US Warships radars work a little differently than your average radar. All US warships use digital systems and satellites that don’t send signals like your standard radar.
Stealth carriers next.
PS. AN/SPY-1 Radar
The AN/SPY-l radar system is the primary air and surface radar for the Aegis Combat System installed in the Ticonderoga (CG-47) and Arleigh Burke (DDG-51)-class warships. It is a multi-function phased-array radar capable of search, automatic detection, transition to track, tracking of air and surface targets, and missile engagement support.
A conventional, mechanically-rotating radar "sees" a target when the radar beam strikes that target once during each 360 degree rotation of the antenna.
Last edited by forget; 23rd Oct 2007 at 11:13.
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
major, you’re reading too many dodgy magazines. For RAdio Detection And Ranging to work it needs to squirt out RF energy. If it doesn’t do that - it’s not Radar.
Also, how do you hide an aircraft carrier? There’s stealth and there’s stealth. Is the picture below from one of you magazines?
From the US Department of Defenc(s)e. Caption says ‘Artists rendition of USS CVN-78 and her escort of five destroyers steaming through the Straits of Hormuz’.
Also, how do you hide an aircraft carrier? There’s stealth and there’s stealth. Is the picture below from one of you magazines?
From the US Department of Defenc(s)e. Caption says ‘Artists rendition of USS CVN-78 and her escort of five destroyers steaming through the Straits of Hormuz’.
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
and MTI moving target indicator processed by a computer in combat areas and airborne assets.
Here, if you still don't understand.
http://www.fas.org/man/dod-101/navy/...ys/AdvRadr.htm