[Elecraft] Fwd: Re: K3 Hi SWR when sending CW

[Adrian]

At the feed point. I guess you didn't gather what my point was in my 
original reply, until Vic spelt it out for you. You don't want any of 
that coax radiating becoming part of the antenna.
If you don't want to wind a UB, then something like this;
> http://www.balundesigns.com/servlet/the-74/1-cln-1-yagis-dipole/Detail

at the feedpoint will do your antenna (and swr reading) wonders.

¨
>
> This is a*current*balun and has the widest operating frequency range, 
> lowest core stress and provides the best overall balance of any balun 
> for given cost, size, and weight. This balun is the best type to 
> balance currents on each side of a 1/2 wave dipole or the driven 
> element of a yagi while providing the perfect transition from a 
> balanced antenna to unbalanced coax feedline.
>
> **
>
> **
>
> Installing this balun will notaffect antenna matching*unless the 
> feedline is acting as part**of the antenna*. This is, of course, not a 
> desirable situationand installing this balun will*correct the problem 
> if**one exists with the antenna*. In beaminstallations, using a 1:1 
> balun in series with theantenna's feed system can substantially 
> improve theantenna's front-to-back and front-to-side ratios. It does 
> thisby providing the antenna's driven elements with balanced current 
> at thefeedpoint and by preventing the feedline fromacting as part of 
> the antenna.
>
>
> It is a seldom appreciated factthat feedlines, which are not 
> adequately decoupled, can act as efficientvertical antennas degrading 
> an otherwise excellentradiation pattern. The addition of a 1:1balun 
> can significantly reduce feedline radiation anddramatically decrease 
> RFI and TVI. Beam antennasespecially benefit from improved balanced 
> drive andsuperior feedline isolation, but even simple dipoles benefit 
> from properly selected and installed 1:1 current baluns. Receiver 
> noise may also be reduced by eliminatingsignal pickup by the coax shield.¨
>


works well.


On 10/04/2012 03:11 AM, Barry wrote:
> Vic,
>
> I think you're on to something.  When I vary the power, below 85W, the SWR
> is 1:1.  Above 85W, it starts creeping up with the power increase.
>
> If I put some ferrites on the coax, but want to keep them indoors, is there
> a best location for them?
>
> Tnx,
> Barry W2UP
>
>
>
> --
> View this message in context:http://elecraft.365791.n2.nabble.com/K3-Hi-SWR-when-sending-CW-tp7563645p7563656.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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