K2: Broadcast Station Breakthrough on the 80 Metre Band

[KBG Luxford]

Hi Gang,

Here's a funny thing.  I have just replaced my two parallel connected
dipoles (one cut for 80, the other cut for 40, connected together at the
apex and fed by a 1:1 balun and RG58CU coax) with a double zepp with
just one set of radiating elements cut a little longer than required to
resonate on 3.6 MHz, and fed with 450 ohm balanced line connected to a
4:1 balun just outside the shack and a short length of RG58CU to the K2
with KAT100.

The apex of the new antenna is some 12 feet or so higher than the old as
I now leave my wind-up tower fully extended.  (Extended height is about
45 feet). Seems to work well, except that I noted considerable broadcast
station breakthrough on the 80 metre band that was not experienced with
the old dipoles.  However, when the Tune button is held and the KAT100
does its magic, the breakthrough disappears.

Curious.

73
Kevin
VK3DAP / ZL2DAP
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[Ken, KA0W]

Hello Kevin!

too much antenna gain - better cut it in half - "HI!"

The tuner maybe acting like a BandPass filter keeping
the the BC out.

You may have sufficient gain at BC frequencies now
with the new antenna.

At times, especially in foggy or wet local conditions,
I receive interesting things when using my 80m 1/4
wave vertical. Within a few short miles are MW BC
towers.

Have fun with the new antenna!

Ken, KA0W
K2/100


   


--- KBG Luxford <[hidden email]> wrote:

> Hi Gang,
>
> Here's a funny thing.  I have just replaced my two
> parallel connected
> dipoles (one cut for 80, the other cut for 40,
> connected together at the
> apex and fed by a 1:1 balun and RG58CU coax) with a
> double zepp with
> just one set of radiating elements cut a little
> longer than required to
> resonate on 3.6 MHz, and fed with 450 ohm balanced
> line connected to a
> 4:1 balun just outside the shack and a short length
> of RG58CU to the K2
> with KAT100.
>
> The apex of the new antenna is some 12 feet or so
> higher than the old as
> I now leave my wind-up tower fully extended.
> (Extended height is about
> 45 feet). Seems to work well, except that I noted
> considerable broadcast
> station breakthrough on the 80 metre band that was
> not experienced with
> the old dipoles.  However, when the Tune button is
> held and the KAT100
> does its magic, the breakthrough disappears.
>
> Curious.
>
> 73
> Kevin
> VK3DAP / ZL2DAP
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

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