[BULK] - [TowerTalk] Omni Directional Antenna on Tower

Dino Darling k6rix at earthlink.net
Thu Jan 6 12:04:06 EST 2005


Actually, don't EVER use LMR-400 for a duplex operation.  There is some 
interaction between the braid and the foil shield that causes noise and 
harmonics in a duplex operation.  Actually, it always does it, but in a 
simplex operation, it doesn't cause a problem.  The RG-214 has a double 
braid and does not have the silver/aluminum interaction and is a good choice.

If you MUST have more information, I will dig it up for you.  I learned 
this from the experts on the Yahoo Repeater Group...
<http://groups.yahoo.com/group/Repeaters/>http://groups.yahoo.com/group/Repeaters/

Also, another trick is to spin the rotor fully clockwise.  Bring the coax 
up to just below the rotor and then wrap it loosely around the rotor in a 
clockwise rotation 1-turn.this is the tightest this loop would ever 
get.  As the rotor turns counter-clockwise, this single loop will open up 
(like a rope opens up when you twist it opposite of its natural 
twist).  Its easier on the coax and it doesn't flex as much as the normal 
way of looping past the rotor.

At 11:47 AM 01/05/2005 -0800, you wrote:
>::I'd put the antenna on top and let it rotate.  Use 100% shielded, or at
>least double-shielded flexible cable (LMR400UF/RG-214/U, etc.) for the rotor
>loop, and  hardline below that point.  I did this with one of my repeaters
>for years.  Used to crack up the users with "you're kind of weak, but let me
>swing the Stationmaster around on you..."  -WB2WIK/6

Dino...k6rix at earthlink.net 


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