[Elecraft] K3 on motorboat.

[Barry]

Full size verticals are hard to do on small power boats. And elevated 
grounds are also hard. Water grounds are usually the most practical, but 
fresh water is not great. I counsel inverted Vs as they are ground 
independent. On power boats that too is a tough trick, but it can be 
done, depending on size of the boat. A 40 meter dipole can be made by 
bending the ends and can be fed with coax through a 4:1 current balun if 
the run to the radio is not too great. It will require a fiberglass mast 
bracketed to the fly bridge. There are several suppliers of good, strong 
push up masts available; I wouldn't go more than about 25 feet which 
should put the feed about 31 or so feet over the water,m close to a 1/4 
wave on 40. This arrangement will allow all band operation above 40 with 
a K3 as the tuner is just plain magic.

73,
Barry
K3NDM

------ Original Message ------
From: "Robert Sands" <k7voradio at gmail.com>
To: "Frank C Richards" <prpntfmr at gmail.com>
Cc: "Elecraft Discussion List" <elecraft at mailman.qth.net>
Sent: 6/9/2020 3:22:27 PM
Subject: Re: [Elecraft] K3 on motorboat.

>Verticals require more attention to ground but the goal should be to
>increase the antenna current, thus increasing radiated signal. ground into
>water seems like a waste but has DC grounding value. I use hung vertical
>dipoles (20 and 15) with no need for ground and they work amazingly well. I
>have tried letting wire or zinc ribbon  strips drop into saltwater to
>ground verticals and there is no value I can detect over something simpler,
>like tying to existing structures or running a above water wire
>counterpoise. Vertical dipoles require no Rf ground and propagate at low
>angle and high efficiency. Far effects over water are what counts, more
>than grounding, except in verticals to get higher antenna current.
>K7VO
>
>On Tue, Jun 9, 2020 at 7:38 AM Frank C Richards <prpntfmr at gmail.com> wrote:
>
>>   Having been in the marine electronics business I was able to successfully
>>  install many HF radios on boats from large steel commercial fishing boats
>>  to a small 28 ft fiberglass fishing boat and sailboats.
>>   Anything metal , engine, fuel tanks,rudder posts,thru hulls, morse control
>>  cables,intercoolers outside of the hull,rub rail sections jumpered together
>>  to form one continuous loop. Dynaplates help but will not work well as the
>>  only source of ground. I once saw a carbon brush riding thru spring tension
>>  on a prop shaft, tying the prop to ground.
>>   It can be tricky as sometimes you get ground loops and you must be aware
>>  of currents that can cause electrolysis.
>>   For the antenna we primarily used a 23 ft whip, sometimes on large vessels
>>  a longwire.
>>   This was before synthesized radios and autouners. My favorite radio was
>>  the
>>  Drake TRM which had a built in manual tuner and a 50 ohm output if you
>>  wanted
>>  to use a trapped vertical.
>>   On  commercial fishing boats you had to leave the dock so that the
>>  outriggers
>>  could be lowered and trawl doors put in the water as this changed the
>>  tuning
>>  quite a bit from being at the dock. Interestingly enough I think the
>>  toughest
>>  time I had tuning  was on an 85 ft steel shrimp boat even with all that
>>  metal.
>>  .
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