another antenna dilema

[dintdinger]

i have a pro 106 and am trying to pick up motorolla apco 25 smartzone signals from towers that are 10 to 15 miles away. i talked to a deputy today and was told i need a omni antenna because the towers switch.
ive put up a mast at twenty feet and am getting sometimes good transmissions via a multi band antenna with rg6 coax. im wondering which anteena to buy and if i should upgrade to heliux and preamp.

any and all suggestions welcome.

 

[SCPD]

Get some Belden 9913, that might help, good stuff so far for me.

 

[ka3jjz]

It would be helpful if we knew what system you were monitoring (go up to the database link in the blue toolbar to the left, under the site logo - follow the links and supply the URL) so we know what freq range you're working, and what this 'multi band antenna' is that you are using.

Offhand, I'd say you might do better with a Yagi if the towers/sites you want to hear are all in the same general direction. I would hesitate about putting a preamp on the 106 - it's already got a hot front end - any more gain and there's a chance you might overload it.

73 Mike

 

[kb2vxa]

The age old rule is height is might. 20' isn't a whole heck of a lot, so go higher if you can.

The choice of antenna is entirely up to you, each set of operating conditions is different so choose one that suits you and not one that suits somebody else with different conditions. Going by general recommendations is just fine but that only narrows down your selection, it won't make the final choice for you.

Myself and others on this forum have done extensive research when it comes to coax for general scanning applications and the conclusion we have reached is you'll get the best bang for the buck with quad shield RG-6. The reasons are it has just about the lowest loss of commonly used cables and by comparison is dirt cheap, an excellent combination. Semi-rigid "hard line" is not only very expensive, requires uncommon connectors and specialized tools to install them but is considerable overkill for this sort of application. Leave the professional stuff to the professionals who make money on the job, they're not the ones paying for it.

FYI Heliax is a trademark of the Andrew Corporation and not a type of transmission line, the type is "semi-rigid" which was the term I used earlier. I put "hard line" in parentheses because it's a misnomer for semi-rigid line, true hard line is hard like a steam pipe and quite often just as large.

 

[dintdinger]

thank all of yall
ok jd i'll look into 9913

mike, the control frequencies are in the 850 range and are digital trunking motorolla xts system.the multi band im using is simply a mobile magnet mount i took apart and cleaned and changed from rg58 to rg6.
i dont know how to locate tower locations, what im told is one is directly south of me and another is west of me and then they are part of a regional system call the harris county regional p25 system

warren,
okim using fence toprail for a mast. if i go up another 20 and guy wire it do u think that will help. rohn tower are expensive.

 

[dintdinger]

oh yeah one more thing... i pick up convential digital with no prob... its just this other motorolla xts p25 digital smartzone system that gurles on some transmissions