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AirMax on hot AM transmission antenna.

Good day everyone.  I'll start off by saying, im no expert....

 

Id like to use an AM tranmission antenna (the red and white ones) to mount an Airmax to.

 

Im told I will need some sort of isolation as the entire tower is the acutal antenna.  Has anyone done this? is it worth it?

 

Thanks in advance!

 

Andrew


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Re: AirMax on hot AM transmission antenna.


@andrewsreg wrote:

Good day everyone.  I'll start off by saying, im no expert....

 

Id like to use an AM tranmission antenna (the red and white ones) to mount an Airmax to.

 

Im told I will need some sort of isolation as the entire tower is the acutal antenna.  Has anyone done this? is it worth it?

 

Thanks in advance!

 

Andrew


Well, in a former life I used to build radio and TV stations, so I can help here.   Yes it's possible, but in most cases yes the AM tower itself is "hot" - it is the actual antenna and the Transmitter connects right to it.   One way to tell is to see if the base of the tower sits on a large ceramic insulator - that's a giveaway.   Also if the guy wires have insulators in them although some newer towers use dielectric guy cable (phyllistran Kevlar cable or the like).   The station engineer can tell you for sure.

 

It's not impossible, but it does add a lot of commplexity to the install.   You need to either mount all your gear on the tower itself while getting power to it (done through an Austin Ring transformer for AC or a choke for DC) or use Fiber Optic (which itself is an insulator) to connect the radios to whatever equipment you have on the ground.   And also have a Proof test done following the installation to insure you haven't chanded the tower's RF characteristics - the FCC mandates that any time you change the tower structure or what's attached to it.   So yes it's possible but should probably be left to a Pro both for your peace of mind and for the Station's license...

Jim

 

" How can anyone trust Scientists? If new evidence comes along, they change their minds! " Politician's joke (sort of...)
"Humans are allergic to change..They love to say, ‘We’ve always done it this way.’ I try to fight that. "Admiral Grace Hopper, USN, Computer Scientist
"It's not Rocket Science! - Oh wait, Actually it is... "NASA bumper sticker
"Just because you can do something doesn't mean you should."my mantra in the Programming classes I used to teach once upon a time...

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SuperUser
Posts: 14,584
Registered: ‎12-08-2008
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Contributions: 1

Re: AirMax on hot AM transmission antenna.


@andrewsreg wrote:

Good day everyone.  I'll start off by saying, im no expert....

 

Id like to use an AM tranmission antenna (the red and white ones) to mount an Airmax to.

 

Im told I will need some sort of isolation as the entire tower is the acutal antenna.  Has anyone done this? is it worth it?

 

Thanks in advance!

 

Andrew


Well, in a former life I used to build radio and TV stations, so I can help here.   Yes it's possible, but in most cases yes the AM tower itself is "hot" - it is the actual antenna and the Transmitter connects right to it.   One way to tell is to see if the base of the tower sits on a large ceramic insulator - that's a giveaway.   Also if the guy wires have insulators in them although some newer towers use dielectric guy cable (phyllistran Kevlar cable or the like).   The station engineer can tell you for sure.

 

It's not impossible, but it does add a lot of commplexity to the install.   You need to either mount all your gear on the tower itself while getting power to it (done through an Austin Ring transformer for AC or a choke for DC) or use Fiber Optic (which itself is an insulator) to connect the radios to whatever equipment you have on the ground.   And also have a Proof test done following the installation to insure you haven't chanded the tower's RF characteristics - the FCC mandates that any time you change the tower structure or what's attached to it.   So yes it's possible but should probably be left to a Pro both for your peace of mind and for the Station's license...

Jim

 

" How can anyone trust Scientists? If new evidence comes along, they change their minds! " Politician's joke (sort of...)
"Humans are allergic to change..They love to say, ‘We’ve always done it this way.’ I try to fight that. "Admiral Grace Hopper, USN, Computer Scientist
"It's not Rocket Science! - Oh wait, Actually it is... "NASA bumper sticker
"Just because you can do something doesn't mean you should."my mantra in the Programming classes I used to teach once upon a time...
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Registered: Monday

Re: AirMax on hot AM transmission antenna.

Jim, Thank you so much for reply!!!

 

Seem like it may be more trouble than its worth. The Antenna does not belong to us but is on our proptery and owner says its fine..  In Canada im sure the CRTC has simular regulations but will have to investigate.  

 

Thank you again for your help!!

Andrew