Elecraft

Antenna problem / phenomenon

Classic

List

Threaded

4 messages Options

GS-3

Antenna problem / phenomenon

Hi all,

I have a new set of mobile antennas, pro am series with magnet mount. Most
works just fine but I have one thing I don't understand. I have a K1 and a
K2 and while the K2 (without tuner enabled) shows an SWR of 2:1 on the 30m
antenna the K1 immediately reduces power to 0.1w and shows SWR 9.9. And
what's most stunning, the KAT1 can't even reduce this 9.9...

Any idea why and most important: what can I do?

Thanks!

Gerhard Schwanz
DH3FAW
http://www.gs-personal.de

_______________________________________________
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

Paul Gates

Re: Antenna problem / phenomenon

You know, Gerhard I have had the same problem at times.
Paul Gates
Elecraft K1 #231
XG1
[hidden email]

----- Original Message -----
From: "Gerhard Schwanz" <[hidden email]>
To: <[hidden email]>
Sent: Monday, May 16, 2005 5:07 AM
Subject: [Elecraft] Antenna problem / phenomenon

> Hi all,
>
> I have a new set of mobile antennas, pro am series with magnet mount. Most
> works just fine but I have one thing I don't understand. I have a K1 and a
> K2 and while the K2 (without tuner enabled) shows an SWR of 2:1 on the 30m
> antenna the K1 immediately reduces power to 0.1w and shows SWR 9.9. And
> what's most stunning, the KAT1 can't even reduce this 9.9...
>
> Any idea why and most important: what can I do?
>
> Thanks!
>
>
> Gerhard Schwanz
> DH3FAW
> http://www.gs-personal.de
>
>
> _______________________________________________
> 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
>

_______________________________________________
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

G3VVT

Re: Antenna problem / phenomenon

In reply to this post by GS-3

The answer to the problem is an old one in that it is difficult to get an HF
antenna to work with a mag mount due to the low capacitance between the
magnetic base and the vehicle body.

VHF/UHF antenna mounted on a mag mount is OK as the effective low
capacitance does not present a problem. I even tried a 3 magnet type of mount on HF
with the same dismal results. Am told that if you can install a very short wide
grounding strap from the mag mount to the vehicle body this can be the answer
to the problem, but admit that I was never entirely successful with this
either.

There seems nothing better than getting a good metallic contact with the
vehicle body to get an HF mobile whip to tune and correctly which is what I had
to do in the end with a bolted on mount.

Bob, G3VVT
_______________________________________________
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

Leigh L. Klotz Jr WA5ZNU

Re: Antenna problem / phenomenon

Administrator

In reply to this post by GS-3

Have you tuned the length of the 30m antenna? Out of the box it might
be wrong.
You also need a ground strap, if you don't want a permanent
installation. I hopr your car is metal, not fiberglass. You may need
some straps to hook other parts of the car together, such as roof to
body, or hood to body, to get more metal in the ground plane. If you
plan to operate while the car is running and use car 12v, you wuill have
much more to do, but if you operate when the car is off, this is
enough.

I operate 40, 30, 20, 17, and 15 with similar antennas (Hamstick or Pro
Am) and a tri-mag mount and a short piece of #14 zip cord (both) to a
screw on the car. For feeding the antenna, I use coax to a balun and
then twinlead through the sunroof. I use the WB6ZQZ step-down balun and
usually use it on the 25 ohm setting, depending on what makes the tuner
happiest.
73,
WA5ZNU / Leigh.
On Mon, 16 May 2005 2:05 am, Gerhard Schwanz wrote:

> Hi all,
>
> I have a new set of mobile antennas, pro am series with magnet mount.
> Most
> works just fine but I have one thing I don't understand. I have a K1
> and a
> K2 and while the K2 (without tuner enabled) shows an SWR of 2:1 on the
> 30m
> antenna the K1 immediately reduces power to 0.1w and shows SWR 9.9. And
> what's most stunning, the KAT1 can't even reduce this 9.9...