"Bill Turner" wrote in message
...
On Fri, 26 Nov 2004 10:14:46 -0500, James wrote:

I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

__________________________________________________ _______

I'd say your system is working pretty well. 50 feet is too long for a
20 meter antenna, however. Your auto tuner is correcting for it, but a
shorter length will actually work better, since the auto tuner won't
have to introduce as much correction and therefore will have lower loss
in the tuner itself.

The vertical part of a ground plane antenna (which is what you have) can
be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet
(rounded off). The exact footage depends on variables in the immediate
environment, but that should be close enough. If you have to have a 50
foot overall wire because of the height of the boat's mast, just put an
egg insulator at the 16.4 foot length to break it up. For multiple
bands, figure the length of each section and put egg insulators where
needed, and then to change bands, just connect a jumper wire across
various eggs to get the correct length. Neat, huh? :-)

Exactly what I was going to suggest. This will be easy to do if you have a
pully on the top end so you can easily drop the wire to change the shorting
straps. With the 50 foot wire, I would be concerned about getting high angle
radiation on 10/15/20 metters. Dog bone insulators might put less capacitive
loading on the top of the disconnected section.

Tam/WB2TT

Also, you can't have too much ground area, within reason. More aluminum
foil or copper is always better.

If you have access to an SWR analyzer such as the MFJ 259, so much the
better. They are highly recommended for making and troubleshooting
antennas.

--
73, Bill W6WRT

Bill Turner wrote:
On Sat, 27 Nov 2004 06:35:49 GMT, 'Doc wrote:


Will it be the
'best' possible antenna? Of course not, but it'll
certainly be adequate...
'Doc


__________________________________________________ _______

More cost, less performance. Amazes me what some people think is
"adequate".

I'd lose the tuner and spend the money on more goodies for the boat.

Oh, well.

--
Bill W6WRT


How about adequate performance and convenience?

Ever been aboard an ocean going sail boat when the waves hit 5 meters
and the wind is howling like a freight train? If not you can't imagine
the fury. I've been there. It's exhilirating but not easy to endure. In
fact it's damned hard work. That is NOT the time to be playing with
knobs and switches trying to tune for a particular band. Believe me, I
will have more imporant things to do. But I do want to know that I can
tranmsit immediately if something terrible happens by just keying the
mic. No fuss.

No offence but I've always been intrigued watching amateur enthusiasts
wiggling knobs and waggling switches. Reminds me of a scene from the
wizard of oz for some reason. Seems so unnecessary in this day and age.

CONVENIENCE is a VERY good a reason as any to use a tuner. And they're
not all that costly either. A few hundred bucks at best.

Just my 2 cents worth.

Jimmy

Bill Turner wrote:
On Sat, 27 Nov 2004 06:35:49 GMT, 'Doc wrote:


Will it be the
'best' possible antenna? Of course not, but it'll
certainly be adequate...
'Doc


__________________________________________________ _______

More cost, less performance. Amazes me what some people think is
"adequate".

I'd lose the tuner and spend the money on more goodies for the boat.

Oh, well.

--
Bill W6WRT


How about adequate performance and convenience?

Ever been aboard an ocean going sail boat when the waves hit 5 meters
and the wind is howling like a freight train? If not you can't imagine
the fury. I've been there. It's exhilirating but not easy to endure. In
fact it's damned hard work. That is NOT the time to be playing with
knobs and switches trying to tune for a particular band. Believe me, I
will have more imporant things to do. But I do want to know that I can
tranmsit immediately if something terrible happens by just keying the
mic. No fuss.

No offence but I've always been intrigued watching amateur enthusiasts
wiggling knobs and waggling switches. Reminds me of a scene from the
wizard of oz for some reason. Seems so unnecessary in this day and age.

CONVENIENCE is a VERY good a reason as any to use a tuner. And they're
not all that costly either. A few hundred bucks at best.

Just my 2 cents worth.

Jimmy

In article ,
Bill Turner wrote:

If you're a purist, a simple L-network at the base will
transform whatever impedance you have to exactly 50 ohms. L-networks of
this type are quite broadbanded and one setting will usually cover the
whole band.

Tuners, begone! :-)

--
Bill W6WRT

In what world does an "L network" not equal exactly what a tuner does
for a wire antenna? An autotuner is nothing more than a binary
incremented L Network with autofeedback of directional power, and phase.
You suggestion is the same thing with no feedback or incremental changes.


Me

In article ,
Bill Turner wrote:

If you're a purist, a simple L-network at the base will
transform whatever impedance you have to exactly 50 ohms. L-networks of
this type are quite broadbanded and one setting will usually cover the
whole band.

Tuners, begone! :-)

--
Bill W6WRT

In what world does an "L network" not equal exactly what a tuner does
for a wire antenna? An autotuner is nothing more than a binary
incremented L Network with autofeedback of directional power, and phase.
You suggestion is the same thing with no feedback or incremental changes.


Me

In article ,
James wrote:

Thanks for the feedback folks. Doc is on the right track. THe tuner
works really well (way to go SGC, nice product!) and the antenna length
doesn't seem to be impeding transmission distance.

Furthermore, the length, although not electrically correct for all
frequencies, is convenient physically for a sail boat.

Glad to hear that the 1000 mile distance I attained was acceptable
performance. My actual planned use is for keeping in touch with other
vessels (friends) that are within a couple of thousand miles tops.
Hopefully it will do the trick.

Thanks for the feedback folks. Muuch appreciated.

Jimmy

With a 50' antenna length and an adiquate RF Ground, one could
consider that a respectable Marine Radio Installation.

One thing that needs to be understood is that ALL Autotuners
have a REALLY BIG difficency that is inherent in their design.
They can NOT tune wires at the Half Wavelength point and 50Khz on each
side. At this point antenna impedance becomes Infinite and can't be
tuned. so a boater must make sure that he never intends to transmit
on the frequency that is at the electrical Half Wavelength of the
antenna. He may need to lengthen ot shorten the wire to adjust
for this condition.


Bruce in alaska
--
add a 2 before @

In article ,
James wrote:

Thanks for the feedback folks. Doc is on the right track. THe tuner
works really well (way to go SGC, nice product!) and the antenna length
doesn't seem to be impeding transmission distance.

Furthermore, the length, although not electrically correct for all
frequencies, is convenient physically for a sail boat.

Glad to hear that the 1000 mile distance I attained was acceptable
performance. My actual planned use is for keeping in touch with other
vessels (friends) that are within a couple of thousand miles tops.
Hopefully it will do the trick.

Thanks for the feedback folks. Muuch appreciated.

Jimmy

With a 50' antenna length and an adiquate RF Ground, one could
consider that a respectable Marine Radio Installation.

One thing that needs to be understood is that ALL Autotuners
have a REALLY BIG difficency that is inherent in their design.
They can NOT tune wires at the Half Wavelength point and 50Khz on each
side. At this point antenna impedance becomes Infinite and can't be
tuned. so a boater must make sure that he never intends to transmit
on the frequency that is at the electrical Half Wavelength of the
antenna. He may need to lengthen ot shorten the wire to adjust
for this condition.


Bruce in alaska
--
add a 2 before @

On Fri, 26 Nov 2004 10:14:46 -0500, James
wrote:

Can anyone comment?

Hi James,

Well, as to the DX range, that has been responded to. So, to add to
all the comments in regard to height of antenna, tuners, automatic
tuners and the rest - another comment.

Take a fishing reel full of the Wireman's Flex weave (no doubt this
will provoke comments about wire corrosion) and drive it. Use your
hoist to pull out the correct height for any band.

I do take note of your admonition about fumbling with knobs, dials,
switches when a rogue wave is overtaking you. Your knottage may vary.

73's
Richard Clark, KB7QHC

On Fri, 26 Nov 2004 10:14:46 -0500, James
wrote:

Can anyone comment?

Hi James,

Well, as to the DX range, that has been responded to. So, to add to
all the comments in regard to height of antenna, tuners, automatic
tuners and the rest - another comment.

Take a fishing reel full of the Wireman's Flex weave (no doubt this
will provoke comments about wire corrosion) and drive it. Use your
hoist to pull out the correct height for any band.

I do take note of your admonition about fumbling with knobs, dials,
switches when a rogue wave is overtaking you. Your knottage may vary.

73's
Richard Clark, KB7QHC

Bill Turner wrote:
On Sat, 27 Nov 2004 11:51:01 -0500, James wrote:


Ever been aboard an ocean going sail boat when the waves hit 5 meters
and the wind is howling like a freight train? If not you can't imagine
the fury. I've been there. It's exhilirating but not easy to endure. In
fact it's damned hard work. That is NOT the time to be playing with
knobs and switches trying to tune for a particular band.


__________________________________________________ _______

Your point is well taken, but this is also NOT the time for equipment
failure. If that nifty tuner gets dunked with a dollop of salt water,
you are dead, RF wise. The KISS principle is your friend.

Anyone who can do a sail change or heave to in 5 meter waves can clip or
unclip a jumper, or better yet, will have the jumper set beforehand.

To each his own.

--
Bill W6WRT




Thanks for the words of wisdom Bill.

In fact I made a point of purchasing a tuner that comes in a water tight
(read that water PROOF according to the manfacturer) case. It's high
up mounted in a lazerette that "theoretically" stays dry. The ground and
antenna stud are both 316 Stainless (highly corrosion resistant and
intended for use in salt air). Furthermore, the electrical connection
between antenna stud and wire is soldered, crimped, and then heat shrunk
with adhesive lined shrink. Instead of using high tension wire for the
antenna connection to the backstay wire, I used tinned copper heavy
gauge insulated electrical wire. The environment that I live in is so
corrosive that, believe it or not I had to strip back the jacket to
expose the tinned copper wire, and then seal the cut edge of the jacket
to prevent salt water ingress between jacket and wire. If that isn't
done even tinned copper wire will corrode. Salt water will creep under
the jacket and corrosion will occur for a few feet distance from the
stripped jacket.

All connections (RF, power and control) between tuner and radio are made
with crimp and solder, then sealed with liquid electrical tape, then
adhesive lined heat shrink. I bought really big insulators to go at both
ends of the wire antenna too. Salt water is conductive and the larger
insulator with heavy ribbing will hopefully reduce the surface coating
of salty water to a level that precludes conductivity. Hopefully. the
copper wire I ran up the mast is on it's own pulley (well it will be
when I find time to go up the mast) and is already a lovely shade of
green. I have a spare, and hope this one lasts a year before needing
replacement.

Even so, I expect to have to service the connections about once a year
or so.

And you thought putting a beam on a tower was hard! Just thought you'd
find the lengths we have to go to in the ocean environment interesting.

The KISS principle is followed where ever I can too. I sincerely agree.
When things go badly on board, it's rarely one big bad thing that bites
ya. It's a string of small problems that...when combined, lead to a bad
day. I guess that's true in a lot of endeavors come to think of it. Last
time I was in a bad storm (a really bad one at that) I was on the radio
seeking information from someone else who had radar (I do not). My
autohelm had failed (a lousy 25 cent pin broke) and so I had to hand
steer in heavy seas. I couldn't leave the wheel. Fortunately the mic on
my marine VHF radio ~just~ reached the wheel from inside. Unfortunately
that is when I discovered that if I pulled on the mic cable it became
very intermittent. And that led to me spending a half hour trying to
raise a nearby boat with radar to ask which way the storm appeared to be
moving. Then the lightning started hitting the water all around
me...from there...well...let's just say it went downhill some.

Simple is good.

Thanks again for the feedback.