I have a Cushcraft X-7 which is not a pure LPDA but uses a log cell.
It is fed thru a 4:1 balun and I route the coax along and taped over the
boom (the tx line is below the boom).
Except on 10m where I do have some unknown problem (F/B is very very
poor), I think I have no current on the outer shield of the coax. I
think this is the case as pattern is very clean and I measured >35 dB
dip off the ends of the antenna compared to front.
73 Juan EA5RS
-----Mensaje original-----
De: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] En nombre de Steve Katz
Enviado el: viernes, 03 de diciembre de 2004 19:36
Para: 'Tom Rauch'; Michael Tope; Jim Lux; Guy Olinger, K2AV; TowerTalk
Asunto: RE: [TowerTalk] elevated short vertical dipole orquarterwave
monopole?
> When I had a gamma matched Wilson 20M yagi, the common mode
> voltage on the coax was so high the coax actually arced
> between the tower leg and the coax shield.
>
> ::Tom, you posted something recently somewhere about LPDA mfrs
> recommending running the feedline along one of the excited booms and
> stuff. Yep, Tennadyne recommends this. I've also seen it recommended
to
> run the coax inside one of the excited booms, where an LPDA's elements
> didn't go through the booms, leaving them hollow. In lieu of this,
which
> seems wrong to me too, how do you recommend routing xmsn line to an
LPDA?
> "Hanging down from the feedpoint for 1/2WL" isn't going to cut it for
most
> of us, that would be a 33' rotor loop...73 de Steve WB2WIK/6
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any questions and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|