[Elecraft] High SWR problem

[David A. Belsley]

Edward:
  Get rid of the coax running from the tuner to the antenna, and get rid of 
the balun.  The balun is completely unnecessary in this situation and is 
only messing things up.  The coax feed is also not helping.  Simply run 
regular wire in its place.  It may be insulated wire if needed.  Attach the 
wire to the single lead output of your tuner (or the center of the output 
coax connector if there is not a screw connector) and use a cp (or set of 
them) on the ground side.  Change the lead-in length if you're still having 
troubles getting a match, but the additional length of the lead in from 
your 20 meter wire should help here already.  Now the total length of your 
antenna is the 20 meters plus the length of the lead in. The cps can be run 
just about anywhere, but the ends should be insulated and separated from 
surrounding objects.

best wishes,

dave belsley, w1euy

--On Monday, August 18, 2003 7:43 AM +0100 Edward Kenworthy 
<edward@kenworthy.info> wrote:

>
>
>
> Transmitter --(coax)-- atu with swr meter --(coax)-- balun -- 20m of
> copper running down the guardian.
>
> There's an earth connector on the atu and the braid leading to the earth
> rod is attached to that. The coax running from the longwire is attached
> to a balun at the antenna end, and to a coax connector on the atu.
>
> Not sure what type of balun it is - I bought the longwire ready-made with
> balun attached.
>
> Edward
>
> On 18/8/03 2:51 am, "Don Wilhelm" <w3fpr@peoplepc.com> wrote:
>
>> Edward,
>>
>> After reading several of your responses, I still don't have a very good
>> picture of how your components (antenna wire, coax, ground braid, and
>> ATU/SWR meter) are connected together. And you have a balun in there
>> somewhere - why? and where is it connected.
>>
>> If a combination like this is to work, you should have the 20 meter wire
>> connected directly to the back of the tuner - either on the center
>> connector of one of the coax jacks or to one side of the tuner's
>> internal balun.  If you use the tuner's internal balun, then the ground
>> wire should connec to the other side of the balun - if instead the
>> antenna is fed from the center connector of a coax connector, the ground
>> will go on the ATU chassis (or to the shell of the coax jack - should be
>> the same).
>>
>> So tell us where the coax and balun are in the system and what type of
>> balun - it could be possible that you are attempting to feed an effective
>> open circuit - which will not work.
>>
>> 73,
>> Don W3FPR
>>
>> ----- Original Message ----- |
>> | > Edward:
>> | > You don't give a lot of information to go on.  I gather your antenna
>> | > is 20 meters long.  Is it end fed or otherwise.  Supposing it is end
>> | > fed,
>> does
>> | > that length include the feed line? or do you have a wire coming from
>> your
>> | > K2 that is 20 meters long total?  If the latter, that length wire is
>> going
>> | > to present a very high impedance on 40 meters (where it is a half
>> | > wave)
>> and
>> | > above.  Perhaps the impedance is too high for your tuner to handle.
>> | >
>> |
>> | It's end fed (is there anyother way to feed a longwire ?) and it's 20m
>> long
>> | plus it's fed by some low-loss coax (with a balun).
>> |
>>
>>
>
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----------------------------------
David A. Belsley
Professor of Economics