[Elecraft] OT: Sloper Dipole Question

Wed Jun 18 19:38:00 2003

I agree with Trev's idea to ditch the coax and use open wire feed; this is 
an excellent idea whenever possible.  However, it is not clear you will get 
a balanced feed with a sloper because the electrical lengths of the two 
legs will differ due to their differing circumstances.  If you really want 
a balanced feed, you need to run the open wire to a transmatch that allows 
each leg to be separately tapped to produce equal current as measured by rf 
current meters in each leg.  Meanwhile, Trev, if you're in Cornwall, I sure 
wish I were with you.

best wishes,

dave belsley, w1euy

--On Wednesday, June 18, 2003 11:52 PM +0100 Trevor Day 
<[email protected]> wrote:

> Hi Chuck,
> It strikes me you can solve your problem and improve performance at a
> stroke by discarding the coax and substituting open wire feeder or 450
> ohm ladder at a push.  It should prevent radiation from the feeder (and
> the possibility of incoming interference the same way) whilst probably
> giving you a broader frequency range with a decent match.
>
> gl
> Trev G3ZYY
>
> In message <3EF06B16.13813.1273A2@localhost>, BlandRanch
> <[email protected]> writes
>> Perhaps a little clarification is in order.
>>
>> I am feeding the antenna with coax.
>>
>> Each "leg" is 33 ft long, so the antenna is targeted for 40M and
>> anywhere else the KAT100 can encourage it to go. The antenna is
>> fed in the middle with the center conductor connected to one leg and
>> the shield connected to the other. I do ground the radio chassis to
>> earth.
>>
>> This is for operations away from home, not the least of which is
>> Field Day (Listen for W6MOT - Motorola Ham Club), so the antenna
>> is hung from a tree, not a metal tower.
>>
>> So, if I spin off of a question Earl asked, does it make any difference
>> which leg is up and which leg is down, with respect to what part of
>> the coax is feeding it?
>>
>> I have appreciated all the discussion and detail. I learn much from it.
>>
>> Thanks guys, for your comments.
>>
>> Chuck
>>
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>
> --
> Trevor Day
>
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----------------------------------
David A. Belsley
Professor of Economics