[Antennas] Mobile Antennas - which shoots best, is strongest?

Fri Jun 16 23:01:45 EDT 2006

Yes, the antenna tuner always belongs as close to the base of the vertical 
as is practical! Otherwise the feed line between the tuner and the vertical 
becomes part of the radiator... and is probably not in the right orientation 
to help your radiation pattern...or the impedance of the resulting radiator 
combination.
Sincerely,
Dr. William J. Schmidt, II K9HZ
Trustee of the North American QRO - Central Division Club - K9ZC
Email: bill at wjschmidt.com
WebPage: www.wjschmidt.com
"If you drink... don't drive. Don't even putt" - Dean Martin.
----- Original Message ----- 
From: "David J. Ring, Jr." <n1ea at arrl.net>
To: "Jack Painter" <223bthp at cox.net>; <Antennas at mailman.qth.net>
Sent: Friday, June 16, 2006 2:24 AM
Subject: Re: [Antennas] Mobile Antennas - which shoots best, is strongest?
> Hi Jack,
>> I agree with you completely. My question was just has Doc noticed a big 2
> or 3 S-unit difference which I believe was caused by using a ATU (the same
> Harris unit he is using - the the vacuum variables) at the whip feed point
> and (as I did) using the same type whip fed directly with coax but with
> about 30 feet of mismatched coax and then terminating on a small MFJ tuner
> sitting on top of my radio. Same radio, same antenna - the difference was
> two different coax runs (unlikely but possible) and the two different 
> ATUs -
> one the Harris at the antenna feed point - and the other the "cheap" MFJ 
> at
> the radio end of the feedline.
>> I love verticals for long range - they are great. They're also great for
> skywave (think broadcast AM and marine 500 kHz CW) but low horizontals are
> great for NVIS propagation.
>> But if I want to do NVIS range, I use a telephone!
>> I think working Japan on 80 meter SSB from New England is exhilerating.
>> 73
> David N1EA
> ----- Original Message ----- 
> From: "Jack Painter" <223bthp at cox.net>
> To: <Antennas at mailman.qth.net>
> Sent: Friday, June 16, 2006 2:28 AM
> Subject: RE: [Antennas] Mobile Antennas - which shoots best, is strongest?
>>> Hi David,
>> The problem with any whip including of marine design mounted on or 
> alongside
> a house is the lack of ground plane. As Doc put it so well, the need for a
> counterpoise is almost as important as any antenna choice, as they all
> require it. This in spite of various design promises.
>> Besides omitting radials (the #1 mistake from most accounts), another 
> common
> problem when trying to residential-mount a marine whip is failing to place
> the coupler/ATU right at the feedpoint of the antenna.
>> Using identical equipment, a small vessel with the whip mounted anywhere
> generally does poorer than a large vessel with the whip mounted anywhere. 
> I
> have never seen comparisons of how the shipboard mounting location affects
> the efficiency and radiation patterns, but we all have examples of the 
> small
> (motor) vessel getting poor-mediocre performance no matter how it was
> mounted. People then try to mount that same marine antenna on a "small
> house" (relatively speaking), use no radials, mount the ATU wherever
> convenient, and then wonder why the thing won't work on 160 meters!
>> Cheers,
>> Jack
>>>> ______________________________________________________________
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