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Author Topic: Stealthy mobile antenna source  (Read 405 times)
KF7TG
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« on: July 31, 2004, 12:36:35 AM »

Does anyone know a source for a VHF/UHF or just a VHF mobile antenna that also works as an AM/FM broadcast antenna?  I thought that I remembered one that looked just like the OEM AM/FM antenna, and was located in the same place, but was also a 2M antenna.  Also anyone that has one or knows about them how well do they work?
Thanks

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K5LXP
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« Reply #1 on: July 31, 2004, 02:34:44 AM »

Stico makes one for BCB/VHF, don't know about UHF coverage though.

Mark K5LXP
Albuquerque, NM
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KG4RUL
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« Reply #2 on: July 31, 2004, 09:00:18 AM »

This seems like it would work but, not many new vehicles use antennas embedded in the windshields these days.  The down side is would you really want an antenna radiating up to 150 watts just above forehead level???: http://www.sti-co.com/embedded.asp

Dennis / KG4RUL

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KB1LKR
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« Reply #3 on: July 31, 2004, 11:43:40 AM »

A 48" (+/-) 5/8 wave whip on the fender should, other than being a bit taller than the typical 31" AM/FM whip, work without attracting a lot of attention -- though not as well as the same (or even a 1/4 wave?) on the roof.

Should be almost as good as a center trunk lip mounted whip, and w/ roughly the same RF field considerations, except rear passengers not front (if front fender mounted) would receive th emost RF)

You'd have to *REALLY* isolate (or switch -- maybe an RF relay, powered by the PTT?) the AM/FM receiver from the VHF transmitter, and you'd want to check the RF field levels at the drivers and passengers positions -- maybe stay at 20/25W max vs. 40-75W full power.

If you went to a 1/2 wave ground plane independant (perhaps a good thing, given the location on one size/corner of the vehicle) it would be a little shorter ~38", but you'd have to hide the matching coil below the fender (or does it need to be above, assuming metal fender?)  
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K5LXP
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« Reply #4 on: July 31, 2004, 11:44:44 AM »

The Stico model referenced is for the rear window, not the front windshield.  All "Rated for 150W" means is it won't melt or arc over up to that power level.  Not too many standard xcvrs these days running that kind of power.  And, RF density hazard levels include the gain of the antenna, which for this model is surely the same or less than a quarter wave (gain isn't spec'd).  After installing a number of "disguise antennas" commercially they almost never work as well as a quarter wave, so be prepared for degraded performance.  The undercover cops just used them for car-to-car or incident site comm's, never routine stuff.

Mark K5LXP
Albuquerque, NM
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KB1LKR
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« Reply #5 on: July 31, 2004, 08:52:01 PM »

See: http://www.sti-co.com/fmn.asp for OEM style stealth fender mounts, The covert High VHF is 132-174MHz w/ 2MHz bandwidth.

They also have a 405-512 MHz w/ 20 MHz BW
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