Signal strength over coxial cable

[CFP387]

I have a base scanner antenna designed to receive 27 - 956Mhz with a 75 foot lead of coxial cable to a scanner in the house. I can't receive any frequencies over 512 Mhz even with the squelch closed, nor can I lock in to any trunked control channel to monitor public safety traffic.

Some have suggested that the problem lies within the length of coax, stating that higher frequencies won't travel the distance from the antenna to the radio while a VHF or low band frequency will. Is there any truth to this theory and why won't 800 frequencies make the distance?

 

[crayon]

What type of cable is it?

 

[LarrySC]

I dont think the issue is the coax. It is rated to the freq you mentioned. Details on the antenna is the factor. Because an antenna is rated for this wide range raises questions. An antenna should have elements cut for each band. You should have VHF/UHF/and 800 elements on the antenna. Otherwise it would be the same as a wet kite string. It also could be rated 27 to 900mHz. Post antenna detail.

 

[CFP387]

What type of cable is it?

I don't have that information in front of me; I'll have to get back to you.

I dont think the issue is the coax....Post antenna detail.

The antenna has elements for each frequency band. I have a 12" tall VHF antenna with a 2 inch screw-in base on top of a high band UHF/800 antennae that are parallel with the ground. There are four of them sticking out in opposite directions (much like a four-way lug wrench lying flat on the ground).

 

[LarrySC]

All of the antenna [+] elements should be Vertical. Any Horizinal would be out of phase unless they are grounded.

 

[richrowl]

Coax signal strength

Larry wrote:

All of the antenna [+] elements should be Vertical. Any Horizinal would be out of phase unless they are grounded
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My first thought on the four horizontal elements was that they may be to form a ground plane. Knowing the make and model of the antenna would help in understanding
it's type and function.