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Comet gmrs base antenna


Ccleveland1226
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I purchased and received a Comet 712EFC within the last couple of weeks. For me the verdict is still out.

 

Mine has not been permanently installed yet. It has only been elevated in temporary fashion to 41’ so I can see what distance I could get with that elevation and see if it was sufficient to get me through the trees. I used a 4 watt radio + Comet to 4 watt mobile and I was only able to get to 2.3 miles before completely unusable. So either I have some technical equipment issues or the antenna still needs more elevation to get past the trees without loads of power.

 

Trying to figure out how to get it higher in a temporary fashion before I commit to a purchase for permanent installation rigging.

 

 

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Just wanted to pass on some information regarding my Comet 712EFC. This past weekend I received my new SWR meter and wanted to see how the antenna faired.

 

I rigged the antenna 11’ above the ground on a PVC pole in my back yard away from buildings and trees. Added 10’ of R58 to connect it to the meter, then connected the meter directly to the radio. On the 462MHz frequencies the SWR was in the range of 1.08-1.10:1. On the 467MHz frequencies it was a consistent 1.0:1.

 

I then had a local ham friend use his meter as a means of validating mine. The results were effectively the same. So in the end, it is good to know that the one I received was very well tuned at the factory given it is not easily field adjustable.

 

Curious to know yours fairs.

 

Michael

WRSH965

 

I've seen some good reviews online for the 10 1/2 foot comet gmrs (commercial) base antenna, I ordered one and it should be coming in by Monday. I'm replacing my current existing antenna and ordered a 239 to n adapter. Anyone have experience first hand with the comet?

 

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I have no complaints with my Comet 712EFC with 50 ' of Times Microwave LMR-400 cable.  Mine is mounted on the side of my house and grounded with an 11 ' grounding rod. I can solidly hit GMRS repeaters in two states from my location with 46 watts.  SWR varies from 1.1 to 1.4 across the band.  Great antenna for the price IMHO.

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I have always been curious about this antenna as to how it seems to work quite well at "5 wave links long."  
Historically, I was taught that antennas typically maxed out at 5/8 wave.

The comet 712 is what is called a “Collinear” design antenna. A collinear antenna is an antenna that is actually comprised of multiple antenna arrayed together that, when paired they way they are, alters the overall radiation pattern and improves the effective gain. In the case of the 712, the gain of the antenna is 9dBi. Its coverage pattern is more like a disc, whereas the basic dipole antenna has coverage pattern more like a fat round donut.

The most popular commercial antennas used for high-performance commercial UHF radio installations are also collinear designs. Commercial grade antenna may have reliable service lives of dozens of years.


Michael
WRHS965
KE8PLM
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