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Author Topic: Airplanes  (Read 5001 times)
KA4NMA
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Posts: 357




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« on: March 14, 2014, 05:32:06 AM »

Listening to the news about the missing airplane, they mentioned some satellite pings were detected 4 hours after the plane disappeared.  I got to wondering and did some google searches.  I read that ACARS communicates directly to ground stations, and that it uses a satellite system.  One newscaster and "experts" mentioned the obsolete HF bands.

I am looking for info in all the different frequencies an airplane uses include transponders, ACARS, etc.  I am also wondering what type of antennas are used.

Randy ka4nma
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W5CBO
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Posts: 72




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« Reply #1 on: March 14, 2014, 07:41:59 AM »

Here's my way out there thoughts on the subject. The plane was hijacked and has been flown below radar to some location where either the passengers have been killed and/or the plane will be used in some future terrorist act.

I said it was crazy but time will tell.
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AF6WL
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Posts: 147




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« Reply #2 on: March 14, 2014, 08:12:42 AM »

SPECTRE

I hope everyone is still alive and the plane was flown to a shallow water landing in the Andaman Islands.
In the Bond film Thuderball, a Vulcan bomber is highjacked and landed in the water and was covered in netting.
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K8AXW
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« Reply #3 on: March 14, 2014, 08:38:49 AM »

CBO:  At lot of people are expressing the same opinion.  However, one thing that needs to be addressed about that theory....the plane would have to have a very large airstrip to land in one piece "for future use."  That would be difficult to cover up.
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K9YLI
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« Reply #4 on: March 14, 2014, 09:09:33 AM »

About 8 years ago I met a guy at the job interview I did.  he had been  in radio  repair in the far east areas. Worked on HF radios on aircraft. But not our usual ones.  Mostly Kenwood, Icom  etc. Vhf would be usless mid pacific..  So I suspect  all over ocean  planes carry  HF  radios.
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NO2A
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« Reply #5 on: March 14, 2014, 10:35:05 AM »

Another possibility is the "Dragon`s Triangle"(google it). I suppose it could have been flown to another location also. In 1950 a Japanese ship disappeared. The rescue ship sent to recover it also vanished. Let`s just hope that if it was hyjacked,nobody was injured or killed.
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ND5Y
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Posts: 4




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« Reply #6 on: March 15, 2014, 07:26:55 AM »

I am looking for info in all the different frequencies an airplane uses include transponders, ACARS, etc.  I am also wondering what type of antennas are used.

Read this: http://wiki.radioreference.com/index.php/Finding_Air_Traffic_Frequencies
and this: http://wiki.radioreference.com/index.php/Instrument_Landing_System_%28ILS%29_Frequencies
Read all the links at the bottom half of this page: http://wiki.radioreference.com/index.php/Aircraft

Here are a few aircraft antenna manufactuers:
http://www.daytongranger.com
http://www.cobham.com/about-cobham/aerospace-and-security/about-us/antenna-systems.aspx
http://www.rami.com
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Tom
W9KEY
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Posts: 1166




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« Reply #7 on: March 15, 2014, 03:28:51 PM »

Here's my way out there thoughts on the subject. The plane was hijacked and has been flown below radar to some location where either the passengers have been killed and/or the plane will be used in some future terrorist act.

I said it was crazy but time will tell.

that was one of my initial (and remaining) guesses as to what could have happened as well.  Then I thought that the plane would need a lot of fuel to fly here and that made me feel a little better.  how far can a 777 fly on a full tank?  If they are alive, let's hope one of those passengers escapes and has a small QRP solar-powered ham xcvr  Wink 
i realize my thoughts are probably naive, but one cannot help but have them ...
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G7MRV
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« Reply #8 on: March 17, 2014, 03:32:15 PM »

The OP asked only about frequencies, not for everyones pet conspiricy theory! We all have ideas of what might have happened, but only the poor sods on the flight actually know!

Lets get back on topic, and leave the speculation to the mass media?

ACARS uses VHF airband for its primary comms to ground stations, but can also route via an aircrafts INMARSAT terminal if available. The final 'pings' detected were INMARSAT 'keep alive' packets from the SATCOM terminal, but were NOT valid ACARS  packets (the ACARS having been disabled)

The SSR transponder, and any ADS-B beacon, operate at a fraction over 1GHz (1.030/1.090)

The aircraft should also have been equiped with registered 'float free' EPIRBS operating on 406MHz. In the event of a ditching at sea, these could have been manually activated, but should have remained at the surface anyway when the airframe sank.

This aircraft should also have had a HF SSB radio available, but perhaps not HFDL.

All these systems can be disabled by the crew, with the exception of the EPIRBs.

The FDR and the CVR (cockpit voice recorder) have ultrasonic sounders to aid in sea location, but these are low powered and only detectable at a few miles range.



Oh what the heck, back to the consipiracies! My initial thoughts were CFIT (controlled flight into terrain, in other words the pilot simply flew right into something he didnt see. This is surprisingly common and is why the Artificial Horizon was invented), or catastrophic depressurisation. But the lack of debris fields and the signals intelligence to me point to either a hostage situation, which would explain the slow release of information to the media whilst negotiations/CRW mission is mounted, or simply, and sadly probably most likely, pilot suicide.
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KE7TMA
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Posts: 472




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« Reply #9 on: March 17, 2014, 04:00:50 PM »

The OP asked only about frequencies, not for everyones pet conspiricy theory! We all have ideas of what might have happened, but only the poor sods on the flight actually know!

Lets get back on topic, and leave the speculation to the mass media?

ACARS uses VHF airband for its primary comms to ground stations, but can also route via an aircrafts INMARSAT terminal if available. The final 'pings' detected were INMARSAT 'keep alive' packets from the SATCOM terminal, but were NOT valid ACARS  packets (the ACARS having been disabled)

The SSR transponder, and any ADS-B beacon, operate at a fraction over 1GHz (1.030/1.090)

The aircraft should also have been equiped with registered 'float free' EPIRBS operating on 406MHz. In the event of a ditching at sea, these could have been manually activated, but should have remained at the surface anyway when the airframe sank.

This aircraft should also have had a HF SSB radio available, but perhaps not HFDL.

All these systems can be disabled by the crew, with the exception of the EPIRBs.

The FDR and the CVR (cockpit voice recorder) have ultrasonic sounders to aid in sea location, but these are low powered and only detectable at a few miles range.



Oh what the heck, back to the consipiracies! My initial thoughts were CFIT (controlled flight into terrain, in other words the pilot simply flew right into something he didnt see. This is surprisingly common and is why the Artificial Horizon was invented), or catastrophic depressurisation. But the lack of debris fields and the signals intelligence to me point to either a hostage situation, which would explain the slow release of information to the media whilst negotiations/CRW mission is mounted, or simply, and sadly probably most likely, pilot suicide.

I'm not sure of any details but I believe that the aircraft's engines were each also supplied with telemetry radios that were independent of any of the on-board and crew-accessible systems, and these continued to send out position updates even after the other telemetry stopped.

It is difficult to tell anything for sure, as there has been a lot of conflicting information regarding this flight.  Malaysian airlines has an abysmal safety record but if the plane had simply crashed I think we'd know more by now.
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ONAIR
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Posts: 1747




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« Reply #10 on: March 18, 2014, 12:02:08 AM »

Just heard a theory on a local repeater that the plane was taken by UFOs, and will soon reappear after the humanoids onboard are tested!  Go figure.
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W1JKA
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« Reply #11 on: March 18, 2014, 03:07:21 AM »

  Another OFF track response: You would think that any countries military who had a satellite in the area at the time would release the results of the jet's engines vapor trail via the infra red sensors that distinguish temp and moisture content signature differences in the atmosphere. Makes you wonder, why all the slow news seepage and secrecy.
« Last Edit: March 18, 2014, 03:14:55 AM by W1JKA » Logged
G4CMY
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Posts: 15




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« Reply #12 on: March 18, 2014, 08:20:43 AM »

.....
I'm not sure of any details but I believe that the aircraft's engines were each also supplied with telemetry radios that were independent of any of the on-board and crew-accessible systems, and these continued to send out position updates even after the other telemetry stopped.

It is difficult to tell anything for sure, as there has been a lot of conflicting information regarding this flight.  Malaysian airlines has an abysmal safety record but if the plane had simply crashed I think we'd know more by now.

Yes - Rolls Royce receive telemetary from all of their engines that are in the air at any time. I guess they would be able to tell if the plane was flying but not necessarily where it was.
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N7BMW
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Posts: 129




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« Reply #13 on: March 18, 2014, 09:44:25 AM »

 Another OFF track response: You would think that any countries military who had a satellite in the area at the time would release the results of the jet's engines vapor trail via the infra red sensors that distinguish temp and moisture content signature differences in the atmosphere. Makes you wonder, why all the slow news seepage and secrecy.

Intelligence agencies never reveal their capabilities.  Wouldn't want the enemy to know what they can do.  Someone probably knows where the plane is but they are not talking.
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KI6LZ
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Posts: 602




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« Reply #14 on: March 18, 2014, 10:59:45 AM »

Capability may exist but sensors must be aimed. Can't monitor the entire world in that detail yet.

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