Topband: FEEDING AN END-FED LONGWIRE

[Brian Mattson]

Hello Sinisa,

I developed this technique years ago, long before I owned an analyzer. I can
tell you that I have owned both Ten-Tec (2) & Yaesu solid state rigs
(without tuners) and all have shown no reflected power at resonance. In
fact, I developed this technique by increasing the turns ratio up & up until
I reached 1:1 SWR.

The transformers are wound multi-filar, as per good engineering practice.
The -43 material allows many fewer turns (u = 850 instead of u=125), and is
recommended for 160 & 80 (& probably 40). If the 9:1 ratio bothers you, the
same results can be had with a pair of 3:1 transformers in cascade. This
approach has one benefit in that the only second transformer requires high
voltage insulation. I use the single transformer version, and have for the
last ten years.

The actual end impedance of the half wave (or multiples) depends upon many
factors, but perhaps most importantly, height above ground. Your ratio may
well be different; however, this is not a real critical number.

Best regards,

Brian  K8BHZ

Subject: Re: Topband: FEEDING AN END-FED LONGWIRE


> Brian Mattson wrote:
>
> > Bottom line is that the end of my longwire looks like about 4,000 ohms
> > impedance at resonance. I simply use an UN-UN to step this down. A 9:1
> > winding ratio gives an 81:1 impedance ratio, so I get a 1:1 SWR at
resonance
>
>
> The ratio of 81:1 would be quite an accomplishment.
> Did you perform any impedance measurements?
>
>
> 73,
>
> Sinisa  YT1NT, VA3TTN