Covert Dual Band Antennas For VHF and UHF

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Jim1348
Posts: 542
Joined: Sun Aug 15, 2004 7:52 am

Covert Dual Band Antennas For VHF and UHF

Post by Jim1348 »

I will be getting a new Impala soon and the boss doesn't want it to look like a porcupine. We switched from VHF high band to 800 mHz trunked at the end of last year, so the Motorola XTS5000 in the XTVA will have a patch antenna and the EVDO aircard will have a little antenna mounted inside. I would still like to be able to use my Yaesu FT-8800 from time to time, but I have very little experience with hidden/covert/disguise antennas for VHF/UHF. My personal prejudice is that they simply don't work very well, but it has been a long time since I have looked at them. I don't really like the idea, but I have given some thought to a Comet B10 mounted inside on the package shelf. The exposure to RF concerns me, but I suppose I could just make sure to always use low power when actually transmitting. http://www.universal-radio.com/catalog/ ... /3918.html
http://www.sti-co.com/antenna-products/ ... f-antenna/

I also looked at the Antenex Phantom Elite, but I can't tell from their webpage if this is a body mount or a trunk lid mount. http://www.antenex.com/index051206.htm
Cowboy
Posts: 290
Joined: Fri May 21, 2004 7:09 pm

Re: Covert Dual Band Antennas For VHF and UHF

Post by Cowboy »

Jim1348 wrote:I will be getting a new Impala soon and the boss doesn't want it to look like a porcupine. We switched from VHF high band to 800 mHz trunked at the end of last year, so the Motorola XTS5000 in the XTVA will have a patch antenna and the EVDO aircard will have a little antenna mounted inside. I would still like to be able to use my Yaesu FT-8800 from time to time, but I have very little experience with hidden/covert/disguise antennas for VHF/UHF. My personal prejudice is that they simply don't work very well, but it has been a long time since I have looked at them. I don't really like the idea, but I have given some thought to a Comet B10 mounted inside on the package shelf. The exposure to RF concerns me, but I suppose I could just make sure to always use low power when actually transmitting. http://www.universal-radio.com/catalog/ ... /3918.html
http://www.sti-co.com/antenna-products/ ... f-antenna/

I also looked at the Antenex Phantom Elite, but I can't tell from their webpage if this is a body mount or a trunk lid mount. http://www.antenex.com/index051206.htm
The Phantom Elite is a standard NMO antenna - they can be used with most any NMO mount, whether it's a 3/4" hole mount, trunk lip or L bracket combo. Expect slightly less performance than a 1/4 wave and much narrower bandwidth.
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Tom in D.C.
Posts: 3859
Joined: Tue Sep 04, 2001 4:00 pm
What radios do you own?: Progreso soup can with CRT

Re: Covert Dual Band Antennas For VHF and UHF

Post by Tom in D.C. »

Any of the "scrunched up" funny looking antennas will have a VHF bandwidth of
no more than 1 mHz, which ain't good for hamming. However, on UHF their
bandwidth gets much better. My experience with putting comm antennas inside
cars has been that in VERY strong signal areas they work okay but the minute
the signal drops off so does the sensitivity of the antenna.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
motorola_otaku
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Joined: Tue Jan 13, 2004 7:03 am

Re: Covert Dual Band Antennas For VHF and UHF

Post by motorola_otaku »

AFAIK, Antenex doesn't make a dual-band VHF/UHF Phantom antenna. They come in monoband-only. And yes, anything less than a 19'' 1/4-wave whip is not going to work very well on VHF.
tvsjr
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Joined: Fri Nov 28, 2003 9:46 am

Re: Covert Dual Band Antennas For VHF and UHF

Post by tvsjr »

He doesn't want a porcupine? One or two external antennas does not a porcupine make... porcupii only start when you cross the double-digit antenna limits!\

Seriously, what about a 3dB gain UHF and a VHF quarterwave on the roof? Or perhaps a Larson NMO2/70B on a lip mount up front? Most people won't even notice it.

BTW, the Comet B10s suck, and have a high failure rate. A friend of mine has a few and has had many problems out of them - outright failures, being improperly tuned from the factory (centered at 155 and 480), etc.

Unfortunately, you're playing with the laws of physics. You wad an antenna up (transit antenna), put it inside a metal box (package tray), etc., you're just not going to get the performance you want.
Will
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Joined: Tue Sep 04, 2001 4:00 pm

Re: Covert Dual Band Antennas For VHF and UHF

Post by Will »

Here is what we use for both VHF and UHF ham, Comtelco A1132. We have had very good results with them.

http://www.comtelcoantennas.com/PDF%20D ... /A1132.pdf
Mraudio
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Joined: Sun Jan 27, 2008 6:48 am
What radios do you own?: Quantar/AS/A-spec./VertexP25

Re: Covert Dual Band Antennas For VHF and UHF

Post by Mraudio »

I for one have had great sucess with the B10 and Diamond clone. Both work very well in my opinion and have used quite a few of them on UC applications. Again just my 2 cents worth
Jeff
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Pj
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Re: Covert Dual Band Antennas For VHF and UHF

Post by Pj »

FWIW, I am using the PCTel 700/800 (which is the Motorola OEM, but in black) via a Diamond MX3000. It works very well on VHF/UHF/800. On the VHF side, it sucks at 144.39, but seems to work tx/rx at 145.xxx and up. The SWR at 146.52 was boarder line on an Astro Spectra pushing 60? watts. I haven't tested it in the current config with a VHF XTL5k, Orion UHF and 800 XTL5k.
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