air band

[motoxtl5000]

hi I have the xts5000 vhf , and love it.I was just wondering if there was a way to make this radio receive below 136.000? even if only to receive lets say some of the air band? Thank you Andy

 

[Astro Spectra]

Aircraft radios use amplitude modulation (AM) while land mobile radios use frequency modulation (FM). Indeed part of the FM radio's circuits remove the amplitude components to improve noise immunity. If you want to listen to aircraft then you might want to look at something like SDR# and a USB tuner module.

 

[Gtaman]

Or pick yourself up an ICOM air band portable. They can be acquired fairly easily.

 

[Notarola]

This is the type of post that belongs at RR. Airband is NOT a toy the FAA has very little sense of humor when it comes to equipment on airband. As a licenced avionics tech I get real nervous when people start putting transmitters on Airband especially when I see that they don't even know that airband is AM. This isnt quite as dangerous as people installing commercial radios in aircraft without having it properly signed off and checked for compliance and interference issues but its a close second.

For anyone considering doing this type of thing the fact the radio can be modded to go below 136 doesn't mean that you should. Responsible editing implies knowing what is where and keeping the equipment in the proper "bands". In other words don't.

 

[PRC148]

Actually yea, I've heard of a guy doing it but you have to tune off freq a bit due to the characteristics of AM vs FM. This was RX only of course. I don't see this as really a "RR type post". It's more of a push the hardware as far as it goes to see what can be done thing. Then again, I'm stupid like that and that stuff intrigues me of for no other reason than to say "yea, I did that" but I don't want to step on any toes so... apologies if I offend or thread hijack.

With that said, the air band is no place to play if a transmitter is involved. If it's RX only sure... just don't generate any RF unless you want holy hell upon you for good reason.

 

[motoxtl5000]

Thank you almost all!! of course I never intended to transmit down here ,I thought that was clear on first post...I love this radio and cary it around all over so had a question is all.Thanks

 

[carbineone]

Actually yea, I've heard of a guy doing it but you have to tune off freq a bit due to the characteristics of AM vs FM. This was RX only of course. I don't see this as really a "RR type post". It's more of a push the hardware as far as it goes to see what can be done thing. Then again, I'm stupid like that and that stuff intrigues me of for no other reason than to say "yea, I did that" but I don't want to step on any toes so... apologies if I offend or thread hijack.

With that said, the air band is no place to play if a transmitter is involved. If it's RX only sure... just don't generate any RF unless you want holy hell upon you for good reason.

I believe it was called slope tuning to somewhat receive AM.

 

[Astro Spectra]

Slope tuning is a trick to receive FM on an AM receiver.

It works because the typical AM IF filter has a sloped response at the IF band edges /-\ either side of the nominal pass band. When the frequency modulated carrier is positioned on the slope by slightly off tuning the power in the IF varies up and down in sympathy with the FM modulation and the amplitude detector generates a varying voltage that follows the modulation delivering the original audio.

 

[kb0uxv]

This is the type of post that belongs at RR. Airband is NOT a toy the FAA has very little sense of humor when it comes to equipment on airband. As a licenced avionics tech I get real nervous when people start putting transmitters on Airband especially when I see that they dont even know that airband is AM. This isnt quite as dangerous as people installing commercial radios in aircraft without having it properly signed off and checked for compliance and interference issues but its a close second.

For anyone considering doing this type of thing the fact the radio can be modded to go below 136 doesn't mean that you should. Responsible editing implies knowing what is where and keeping the equipment in the proper "bands". In other words don't.

As a person in public safety who also manages the local astro25 TRS, I feel the same way about people hacking radios to receive the local system. Sure you can do it safely, but people either screw it up or affiliate intentionally. The last guy who was doing that was affiliating to drag traffic he wanted to scan to sites he was on. So it not only is causing loading issues on sites but also interfering with the real ID he cloned.

 

[carbineone]

As a person in public safety who also manages the local astro25 TRS, I feel the same way about people hacking radios to receive the local system. Sure you can do it safely, but people either screw it up or affiliate intentionally. The last guy who was doing that was affiliating to drag traffic he wanted to scan to sites he was on. So it not only is causing loading issues on sites but also interfering with the real ID he cloned.

So are you saying that all discussions about modifications should be banned ? I don't think it will happen on this site and they have removed some information that would make it very easy for amateurs to mod trunk systems.

 

[Notarola]

No we will not ban discussions on modifications. As responsible people we do try to keep the discussions above the beginner lever. Our main concern is having a bunch of people doing as carbineone is describing. For that reason we do not allow discussions on using, creating or editing system keys or specific system parameters. Anyone with the appropriate background will know enough to be able to work within these limitations. We openly encourage people to post modifications and edits to software and hardware provided they meet the general rules for the site.

My concern was based on the fact that some may knowingly or unknowingly interfere with AV band operations, remember at 20,000 feet you cant pull over and fix a problem. I have personal experience with agencies installing their own equipment in aircraft and later experiencing problems. One case in point was a TRS mobile installed in an aircraft. When the aircraft was in auto-pilot (yes they do use it LOL) and the radio was trunked to one of the TRS freqs the autopilot was saturated with the rf causing the aircraft to attempt a severe left uncoordinated turn. Fortunately the auto-pilot circuitry interpreted this a a failure of the auto-pilot and dropped itself back to manual mode and triggered the fail alarms.The aircraft when experiencing the failure experienced a hard sway to the left causing the pilot and passengers a little stress in the process. If the equipment had been installed by myself or my staff all freq would have been ground tested for such issues. For those interested the solution we made was to use a simplex encrypted freq to a remote receiver/transmitter that was then coupled into a dispatch console to be outputted on the TRS system.

The other side of the coin is the FAA and lots of pilots know what a Av band radio looks like and sounds like, in some cases all it would take is for a pilot(perhaps a nosy one) to see the radio or hear you talking about it and make that call to the FAA. The FAA has an incredible amount of authority and in many cases they are judge, jury and executioner. the fact that it only RX will not carry a lot of weight with them they tend to err on the side of overcautious. With the FAA if in doubt the answer is always NO, this attitude has probably saved countless lives and millions in property damage etc.

 

[logitec]

The best thing to do with those idiots is to deal with them harshly and make an example of them. He was clearly breaking the law by affiliating.

True receive only will not get a person in trouble because there's no way to know you're out there, unless you do something stupid with your radio in public.

As a person in public safety who also manages the local astro25 TRS, I feel the same way about people hacking radios to receive the local system. Sure you can do it safely, but people either screw it up or affiliate intentionally. The last guy who was doing that was affiliating to drag traffic he wanted to scan to sites he was on. So it not only is causing loading issues on sites but also interfering with the real ID he cloned.