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

Sat Jun 17 10:26:01 EDT 2006

Hi David,
I think we may be mincing words... the physical structure of the antenna may 
very well be 35 feet ...but the electric/ radiating part is 33 feet (I've 
measured it... I also have a nice frequency-impedance chart I'll send you 
off-line that is very interesting). You probably know (if you have Bill 
Sabin's book) that the 601 was made with transforms JUST FOR this vertical.
I do pressure up the tuner with nitrogen, although I don't monitor it like I 
should. The nitrogen is very cheap (7ドル per cyl here), and it can save a 
bunch of headaches as you point out. I never tune full power though... only 
at 150 watts or so. Once matched, the thing will take full power +++++++. 
I've never had it arc or act flaky.
To determine the correct number of radials to use (those who believe in some 
rule of thumb for number of radials are just fooling themselves)... since I 
couldn't accurately measure the ground conductivity and make calculations, I 
set up a fixed point field strength meter at some distance... and also 
plotted the antenna impedance. When both stopped changing as I added 
radials, I knew I was at the limit.
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: "Dr. William J. Schmidt, II" <bill at wjschmidt.com>; 
<Antennas at mailman.qth.net>
Sent: Saturday, June 17, 2006 7:27 AM
Subject: Re: [Antennas] Mobile Antennas - which shoots best, is strongest?
> Hello Bill,
>> That's the one we had, Bill. The feed point was via what looked like a
> "high voltage wire" about two feet from the bottom that goes into the 
> centre
> of the vertical. The only shock to me what that ours were 35 feet and I
> always wanted them to be 33 feet to make them better on 40 meters! Of
> course we worked mostly 2, 4, 6, 8, 12, 16, 22 and 25 MHz on HF. They
> worked best on the 6 to 12 MHz range. We had a 400 foot long inverted L
> antenna for MF (500 kHz) that worked very very well on the higher bands as
> it was inline with the ship's direction and the stations we needed to QSO
> were in that direction (or reverse)!
>> On 160 meters, I used to work F8OB from near HC8 - he always wanted to 
> work
> KH6 and that night I was called by Jack KH6CC - I could hear them both -
> Jack and his good ears could just hear F8OB but conditions in France 
> weren't
> as quiet. Almost only counts with horseshoes and handgrenades.
>> Great antenna, you didn't mention if you presurized the ATU with nitrogen.
> We found that necessary to keep the gremlins out of the box and to 
> minimize
> any arcing inside from tuning faults.
>> 73
>> David N1EA
>> ----- Original Message ----- 
> From: "Dr. William J. Schmidt, II" <bill at wjschmidt.com>
> To: "David J. Ring, Jr." <n1ea at arrl.net>; <Antennas at mailman.qth.net>
> Sent: Friday, June 16, 2006 11:30 PM
> Subject: Re: [Antennas] Mobile Antennas - which shoots best, is strongest?
>>> Name is Bill.
>> The Shakespeare vertical I have is not that current 222 boat vertical, but
> rather the mil. one they built for the Navy that bolts to the decks of
> ships. It comes in two sections, tapers from 1 inch at the top to 5 
> inches
> at the base, has a four bolt flange at the bottom that is about 10 inches 
> in
> diameter. The feed point is about 24 inches up from the flange, it has
> twelve wires running up the inside of the fiberglass structure, and will
> handle 10 kW. Weighs about 80 pounds. It will handle two 3x4 flags 
> nicely.
>> The tuner is right at the base of the antenna...mounted on the concrete...
> and the feed wire is about 24 inches long #6 solid copper wire. The tuner
> is covered by bushes and is fed with 7/8" heliax that is out about 70 feet
> from the house. There are two ground rods (one for the vertical and one 
> for
> the tuner), and the radial counterpoise of #6 wire in a 6 foot diameter
> circle that the radials connect to at the base. there are 225 #12 radials
> connected to the counterpoise that were buried in my yard using my 
> patented
> radial burying device.
>> I suppose we all could devise other stealth antennas that work 
> better...but
> I have not seen one yet.
>> I have a good story to go with this: While I was burying the radials for
> the antenna... my neighbor came out and asked why I was burying wire in my
> yard. We have moles here so I said "well, its to keep the moles out of my
> yard!"... to which he promptly said "well, when you finish... can you put
> some down in my yard too?!!!!!".... so I just extended my radials into his
> yard!
>> Sincerely,
>> Dr. William J. Schmidt, II K9HZ
> Trustee of the North American QRO - Central Division Club - K9ZC
>>