[TowerTalk] Voltage at ends of yogi parasitic elements?

[Tom Osborne]

A friend here had a fixed 2-el quad on 80 and used a relay to switch the
parasitic element from reflector to director.  He burned out some relays
before he finally got some high power vacuum relays.  They seemed to work
OK.  73
Tom W7WHY


On Mon, Oct 17, 2016 at 9:44 AM, john at kk9a.com <john at kk9a.com> wrote:

> That is a good question.  Years ago I thought of building an 80m vertical
> with a relay on top to make it a 160m inverted L at my P40A home but I did
> not know if even a vacuum relay would hold up and I knew that there would
> be RF issues with the control wires running down the vertical. I had never
> seen it done and did not want something likely to fail. If you are just
> changing band segments most manufactures are using switchable loading
> coils at the feed point.
>
> GL
> John KK9A
>
>
> To:     towertalk at contesting.com
> Subject:        [TowerTalk] Voltage at ends of yogi parasitic elements?
> From:   Rob Katz <rob.katz at thelegacycenter.com>
> Date:   Sun, 16 Oct 2016 23:09:11 -0400
>
>
> I’m playing with some wire yagis, and I’d like to put relays at the ends
> of the
> parasitic wires to switch the director to a reflector (and vice versa).
> If I’m
> driving the antennas with a full 1.5 KW, what would be the maximum voltage
> that
> I can expect at the ends of the PARASITIC elements?  Even a rough estimate
> would be useful, I just need to get a sense of what kind of a relay I would
> need to use.
>
> 73,
>    Rob  K4OV