Oh, now I get it! This is the cellular antenna company in FL that
makes the 3W linear amp for cellular phone!

Awful lot of smoke 'n mirrors from these guys.....



On Thu, 22 Jan 2004 18:40:46 -0500, "Doug Dotson"
wrote:

What is a 23' "Digital" antenna?????

www.digitalantenna.com

The VHF digitals got great reviews in PC a few years ago. I suspect
the SSB antennas are high quality as well.

Doug, k3qt
s/v Callista



Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!
Let's do what Europeans have been doing for centuries.
DIVIDE UP THE SPOILS OF OUR CONQUEST! Gas will be
$US0.50/US gallon again, STUPIDS!

On Fri, 23 Jan 2004 01:32:35 GMT, Gary Schafer
wrote:

On Thu, 22 Jan 2004 18:40:46 -0500, "Doug Dotson"
wrote:

What is a 23' "Digital" antenna?????

www.digitalantenna.com

The VHF digitals got great reviews in PC a few years ago. I suspect
the SSB antennas are high quality as well.

Doug, k3qt
s/v Callista



Everybody tries to cash in on the word "digital" like it is some kind
of magic. Kind of deceptive if you ask me. Even if it is only their
name.

I see on their web site that they have discovered some new laws of
physics!
A 24 foot HF antenna that has an swr of less than 2:1 over the entire
2-30 mhz range when used with a tuner. Isn't that amazing!

Likewise with their VHF antenna they have discovered a new ground
system that lowers the radiation angle of their 6 db antenna to make
it more efficient than others. Just amazing!

I wonder if it is digitally encoded to perform those miracles.

I remember back when ICOM marketed an "automatic" tuner for long wires
when I first retired and was working part-time at the ARRL as an
Assistant Tech Editor. The ARRL lab purchased one and had it xrayed
at a local orthopods office - turns out it was a really big dummy load
that you could attach a piece of wire to. ;)

Today, I imagine it would be called a digital tuner. ;)

Later,

Tom
S. Woodstock, CT
----------
"The wildness and adventure that are in
fishing still recommend it to me."

Henry David Thoreau
"Walden" (1854)

On Thu, 22 Jan 2004 06:00:09 -0600, "Keith"
wrote:

Well, now that my SSB is up and running, I have one more minor problem ( I
think). Whenever I key up the mike to talk, some of the electronics go nuts,
like the Link 20 (near the grounding foil), the VHF goes blank and one of
those "touch" 110 lamps goes on and off. The radio tech that got me up and
running said these were symptoms of reflected power. I'm using a 23' digital
antenna, and seem to be transmitting well. Is there anything I can do about
this, or should I even be worried about it?

If it's a symptom of reflected power, then why didn't he check for it
and correct it?

Do you have an SWR meter and know how to use it? Does the radio have
a automatic tuner? Do you have good grounds? These are all things
the "tech" should have checked for you if he knew what he was doing.

It does sound like you are radiating all over the neighborhood - there
are some things you can do to cure the problem if you are comfortable
with the technical side of things. Check the grounds on the radio and
the antenna and make sure they are good (clean connections, good
connections, etc.), make sure the antenna is placed as far away from
the radio as practical, the antenna lead is not frayed or possibly
broken internally (you can use an ohm meter to check for that -
continuity), make sure the lead is long and routed properly, just
those kind of common sense things.

If that doesn't cure the problem, then it's ferrite beads, clamp on
chokes, antenna trimming - stuff a tech SHOULD be able to do.

Later,

Tom
S. Woodstock, CT
----------
"The wildness and adventure that are in
fishing still recommend it to me."

Henry David Thoreau
"Walden" (1854)

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel and
electronics, etc.

2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate. I
plan to add some more foil and connect the fuel tanks and run some radials
down there as well. Lets see: the run from the radio to the antenna tuner is
about 25', and the run from that one to the dynaplate is about 10'.

No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

No, my hand doesn't burn when transmitting! ;-)

Yes, I believe the VHF cable needs replacing. It's old and probably cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same chase.
I don't think I connected the sheild to ground though... I'll fix that.

--


Keith
__
Money can't buy happiness, but it sure makes misery easier to live
with.
"Larry W4CSC" wrote in message
...
On Thu, 22 Jan 2004 06:00:09 -0600, "Keith"
wrote:

Well, now that my SSB is up and running, I have one more minor problem
( I
think). Whenever I key up the mike to talk, some of the electronics go
nuts,
like the Link 20 (near the grounding foil), the VHF goes blank and one of
those "touch" 110 lamps goes on and off. The radio tech that got me up
and
running said these were symptoms of reflected power.

You need a new radio tech who WASN'T a CBer. These are symptoms of
RADIATING RF ENERGY out a tuned antenna.....in an RF transparent,
unshielded, plastic boat! The RF energy from the backstay or whatever
you're tuning for an antenna, passes THROUGH everything on the boat
and will wreak havoc with everything that is A) solid state
electronics and B) unshielded, like marine electronics crap with bare
wires marked NMEA + to ground in an unshielded plastic box,
themselves. Damned digital circuitry goes CRAZY...BERSERK when a
good, strong RF field just overruns the data stream, gets rectified by
a zillion tiny transistor junctions into DC bias that screws
everything. My ham station (1500W PEP) nearly blew the neighbor's big
stereo speakers clean out of the cabinet when my RF induced serious
signals into his speaker wires and fed it into the 800 watt power
amplifiers.

Hams know better than to buy touch lamps......

The VHF makes me think its antenna coaxial cable may have a broken
shield connection or, worse yet, has a resonant ground connection to
it. 1/4 of a wavelength back from your ground plate, and every odd
multiple of 1/4 wavelength back from your ground plate is a HIGH
VOLTAGE RF lobe caused by the ground wire acting like an antenna. If
you're so lucky as to have just the right length, 1/4 wavelength from
the groundplate where the RADIO is attached, the RF on the "ground" of
the VHF radio will drive it nuts. RF is blasting away on the OUTSIDE
of the VHF coax cable, every time the HF keys up. If the radio is
near just the right 1/4 wave point from its ground plate (or the DC
power wiring is near 1/4 wavelength to the HF frequency, the whole
thing will be RF "hot" and may do anything. Try disconnecting any
grounds (except battery - of course) you may have attached to it and
see how it does. Pull on those PL-259 coax connectors to see if the
shield braid is firmly attached to them, too.

The link is easy to fix. Run FOIL SHIELDED, multiconductor cable
between the Link and its big shunt and battery connections to keep the
unshielded wires you probably have now from acting like a big HF
antenna to receive the SSB transmitter and feed it to the Link's
damned computer chips. EVERYTHING on the boat needs foil shielded
signal/data wiring. Connect the foil shield to the ground or battery
negative post on the Link. Leave the other end foil and drain wire,
where it comes up to the battery connections, UNCONNECTED. This makes
a Faraday Shield, named after Michael Faraday (discoverer of
capacitance). This unconnected shield encasing the control wiring
keeps the RF OUTSIDE the cable from coupling to the wires INSIDE the
shield feeding the computer circuits.

I'm using a 23' digital
antenna, and seem to be transmitting well. Is there anything I can do
about
this, or should I even be worried about it?


Digital antenna? It transmits DATA instead of RF??!....????????

What does this antenna look like and how far is it located from the
scrambled electronics. Lionheart's AT-140 antenna tuner sits on top
of the aft cabin right behind the cockpit-mounted mizzen mast. The
insulated backstay's tension screwjack bolts to the fiberglass next to
it and the tuner has a 8" stainless steel wire connecting to a
hoseclamp around the jack. The whole cockpit is RF hot because it's a
couple of feet from the main antenna.....(sigh).


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!
Let's do what Europeans have been doing for centuries.
DIVIDE UP THE SPOILS OF OUR CONQUEST! Gas will be
$US0.50/US gallon again, STUPIDS!

On Fri, 23 Jan 2004 08:05:10 -0600, "Keith"
wrote:

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel and
electronics, etc.

I have an M802 on Lionheart with the AT-140 tuner. Its major problem
is the tiny interconnection plugs that connect the tuner control
circuit to the main chassis of the radio. It's a dumb, STUPID
design.... I've had lots of trouble keeping the connection where it
plugs into the radio. The pins in these tiny connectors was designed
to connect a circuit board plug with a tiny cable going between
circuit boards INSIDE radios.....NOT BIG CABLES OUTSIDE RADIOS.
Idiots.

I assume your LCD display on the 802 is reading TUNE at the top so the
control cable must be making connections. The cable MUST BE SHIELDED,
FOIL SHIELDED. This keeps the RF from screwing up the tuner's data
interconnect.

At the tuner end, have your technician eliminate half your tiny plug
problems by opening the AT-140's top sealed cover (yeah, all those
screws). Unsolder the pigtail wire going from the main circuit board
inside the tuner, out through the watertight fitting to the stupid
little unwatertight plug. Throw the pigtail overboard to keep it from
contaminating anyone else's boat. Now, pull your control cable
through the watertight fitting and dress the wires so you can solder
them to the little solder rings on the main board of the AT-140.
Tighten down the watertight fitting to seal the cable to the box. I
used a dot of RTV on the inside around the cable to make sure.
Re-close the AT-140 cover paying attention that the rubber ring seal
is in place, properly. Easy on the screw torques so you don't crack
the cheap plastic. Half your control cable problems are over. I may
change out the other half on the radio to a proper connector after the
warranty runs out.


2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate. I
plan to add some more foil and connect the fuel tanks and run some radials
down there as well. Lets see: the run from the radio to the antenna tuner is
about 25', and the run from that one to the dynaplate is about 10'.

You already have lots more grounds than I do on Lionheart. Looks nice
to me. Any metal screen you can add to the inside of the hull really
makes a great coupling to the seawater through the hull. (It's a nice
capacitor).


No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

You don't need to worry about this SWR nonsense. The Icom M802 will
not transmit until it is satisfied the overall SWR of the system is
acceptable, near perfect. That's what the tuner is for. With your
short antenna, however, you may find it won't tune some of the lower
frequencies below 4 Mhz. The short whip IS part of your interference
problems. All the radiation of 150 watts of RF power is happening on
the length of this short whip.....WAY TOO CLOSE TO THE SENSITIVE,
UNSHIELDED OR POORLY SHIELDED ELECTRONICS it is tearing up.

There is also a lot of radiation coming from the strap to the
dynaplate. It's the other half of a dipole antenna and the tuner is
actually in the middle of it. There is no ground at any tuner unless
the tuner is using a steel deck for ground right under it. This is
just normal. There's nothing you can do to change it. If it didn't
radiate, noone would hear you!...(c;

No, my hand doesn't burn when transmitting! ;-)

Naw. It's only 150 watts. Too much cellular phone propaganda trying
to convince the public RF is dangerous so they can turn the phone
power down without the unsuspecting public, whos phone range just went
way down at 200 mw, raising hell with the FCC. 150 watts isn't high
power and, unless you make direct contact with the upper end of the
whip, won't burn you. 650 watts from my ham radio mobile antenna with
the high voltage corona spraying off the top and ends of the big
capacitor hat, WILL burn you...(c;

Yes, I believe the VHF cable needs replacing. It's old and probably cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same chase.
I don't think I connected the sheild to ground though... I'll fix that.

The shield only should be connected to the LINK's SYSTEM GROUND, NOT
THE FOIL. Hooking it to the tuner's foil WILL induce a lot of current
into the cable. Only hook it on the end where the Link display is and
ONLY to the Link, itself. Tape off the foil shield on the sensor end
so it can't make contact with anything. That's a Faraday Shield.
It's not part of the signal ground for the Link.

I don't like running ANY data cabling anywhere near, to say nothing of
in the same trunk, as the RF grounding system. That whole RF
grounding system is radiating like hell! Running it beside the link
cabling, which is NEVER 100% shielded, is going to cause trouble.
Take the Link cable out of this wireway, along with everything else
with data or hooked to a transistor......or reroute the RF grounding
system to someplace by itself. Don't even run it alongside DC wiring
because the DC wiring in the boat will all become very RF "hot"
creating its own problems....especially with these damned fancy
battery chargers.
--


Keith
__
Money can't buy happiness, but it sure makes misery easier to live
with.

Money can buy a lot of happiness. Take me to a strip joint and let's
test this theory in action!...(c;


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!

An antenna tuner does not belong on the bridge! That is the worst
place for it.

The first thing I would do is to get that tech back and make him put
the tuner where it belongs, In the bilge! Right next to the ground.
You must have a very short ground lead. The length you have now comes
no where near being ground. You might get away with it on 2 Mhz but
not anything higher.

Mount the antenna down near the deck if you have to. Keep the antenna
as far away from other electronics AND wiring as you can.

It will not hurt to have a long antenna lead from the tuner to the
antenna as long as it is in the clear and away from other wires.
Remember that the antenna lead IS part of the antenna, just as much as
the whip is.

The most important thing is to have a SHORT ground lead. Right now
your ground lead is acting as part of your antenna and coupling into
all the other wiring. Especially your LINK system with the leads right
next to the ground lead. (which in your case is part of the antenna)!!

Once you have the proper ground then it is a much easier job to start
to eliminate RF being picked up directly from the antenna. The problem
now is that it is probably being picked up from both the ground lead
and the antenna. It is very difficult to deal with both.

Once a lead leaves the ground connection (connection at the dynaplate)
then the rest becomes antenna. It doesn't matter what side of the
tuner it is on.

Remember "if it isn't ground then it is antenna".

Regards
Gary


On Fri, 23 Jan 2004 08:05:10 -0600, "Keith"
wrote:

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel and
electronics, etc.

2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate. I
plan to add some more foil and connect the fuel tanks and run some radials
down there as well. Lets see: the run from the radio to the antenna tuner is
about 25', and the run from that one to the dynaplate is about 10'.

No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

No, my hand doesn't burn when transmitting! ;-)

Yes, I believe the VHF cable needs replacing. It's old and probably cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same chase.
I don't think I connected the sheild to ground though... I'll fix that.

In article ,
"Keith" wrote:

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel and
electronics, etc.

2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate. I
plan to add some more foil and connect the fuel tanks and run some radials
down there as well. Lets see: the run from the radio to the antenna tuner is
about 25', and the run from that one to the dynaplate is about 10'.

No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

No, my hand doesn't burn when transmitting! ;-)

Yes, I believe the VHF cable needs replacing. It's old and probably cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same chase.
I don't think I connected the sheild to ground though... I'll fix that.

--


Keith

Well Keith,
Sounds like the rest of the folks have chimed in on your problems, and
nailed down the fixes. I really like Gary's comments, as he seems to
have a good handle on what is going on. Larry is ok for some things,
but Larry, 100 watts will certainly burn you from the grounded Micholder
button on the mic during transmit, If the ground system isn't good
enough to support the antenna at the freuqency of transmission. The
Radio Ground becomes part of the antenna, and you then also become part
of the antenna, and if you are lower impedance than the ground system
you get the Rf Current instead of the Ground system. It happens, not
alot but it does happen, less now with autotuners, but it still happens.

Keith, you need to get a new Marine Radio Service Tech! One who actually
has been around since BEFORE autotuners existed. The guy you had was an
idiot, and needs to go back and get a refund on his training. You should
also get a refund on anything you paid him, BIGTIME. I know that
COMPITANT Marine Radio Service Tech's are hard to come by, as most have
left the field because there just ins't any money in the Service end of
the business anymore, but look around some more and find one.


Bruce in alaska
--
add a 2 before @

(sigh) Where DO they get these crazy ideas?......

Lionheart's tuner is 2' from the insulated backstay on top of the aft
cabin. Wanna see my QSL card from Osaka, Japan on 15 meters? I was 5
by 6 with just the little 150 watt transmitter. Not bad, given the
awful conditions of the ionosphere these days and all the masts
suckin' up my signal from Ashley Marina......

"Ground" is a relative thing in RF. You don't even need a "ground"
ground. What you need is a slightly longer than 1/4 wavelength radial
system from the tuner laid out flat. But, alas, that's not practical
because my captain keeps bitching at me every time he trips over my
ground screen, so we compromise with a copper strap to the engine
block and my trailing wire behind the boat while at sea, creating a
giant L antenna with the tuner in the corner of the L. Man, that
works great!

Putting the tuner in the bilge, you have a problem. The "radiating
element" starts at that high voltage terminal on the other end of the
tuner. ANYTHING CONDUCTIVE anywhere near (10'?) it will become part
of the tuning problem and part of the load on the radiating element.
Any boat wiring anywhere near that radiating element WILL suck off
your signal into its light bulb loads, and shunt off your signal to
anything it's connected to.....subtracting from what goes on the air.

Nope....doesn't wash. The tuner needs to be as close to the antenna
as possible and the antenna needs to be as far away from any other
metal objects as you can get it. Unfortunately, in a boat, that's
never far enough unless you're on a ship. Go visit any Navy ship and
notice how the antenna tuners are all mounted right UNDER the bottom
of those 35' nice aluminum whips sitting on huge insulators. Lucky
steel hull owners have great ground planes. For the rest of us, hook
as many different ground paths as you can from the ground lug on the
tuner to as much metal and ground plates as you have available. The
more the better.

(Engineers note on trailing grounds - Don't put something shiny on the
trailing end to haul out the wire behind you. "Something" ate my beer
can and half the trailing wire!)



On Fri, 23 Jan 2004 17:22:54 GMT, Gary Schafer
wrote:

An antenna tuner does not belong on the bridge! That is the worst
place for it.

The first thing I would do is to get that tech back and make him put
the tuner where it belongs, In the bilge! Right next to the ground.
You must have a very short ground lead. The length you have now comes
no where near being ground. You might get away with it on 2 Mhz but
not anything higher.

Mount the antenna down near the deck if you have to. Keep the antenna
as far away from other electronics AND wiring as you can.

It will not hurt to have a long antenna lead from the tuner to the
antenna as long as it is in the clear and away from other wires.
Remember that the antenna lead IS part of the antenna, just as much as
the whip is.

The most important thing is to have a SHORT ground lead. Right now
your ground lead is acting as part of your antenna and coupling into
all the other wiring. Especially your LINK system with the leads right
next to the ground lead. (which in your case is part of the antenna)!!

Once you have the proper ground then it is a much easier job to start
to eliminate RF being picked up directly from the antenna. The problem
now is that it is probably being picked up from both the ground lead
and the antenna. It is very difficult to deal with both.

Once a lead leaves the ground connection (connection at the dynaplate)
then the rest becomes antenna. It doesn't matter what side of the
tuner it is on.

Remember "if it isn't ground then it is antenna".

Regards
Gary


On Fri, 23 Jan 2004 08:05:10 -0600, "Keith"
wrote:

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel and
electronics, etc.

2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate. I
plan to add some more foil and connect the fuel tanks and run some radials
down there as well. Lets see: the run from the radio to the antenna tuner is
about 25', and the run from that one to the dynaplate is about 10'.

No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

No, my hand doesn't burn when transmitting! ;-)

Yes, I believe the VHF cable needs replacing. It's old and probably cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same chase.
I don't think I connected the sheild to ground though... I'll fix that.


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!

I tried the trailing wire bit last spring on the way back across the
GS. Didn't seem to make any difference over just having the
ground connected to a thru-hull. I guess it depends upon the
specifc installation.

Doug, k3qt
s/v Callista

"Larry W4CSC" wrote in message
...
(sigh) Where DO they get these crazy ideas?......

Lionheart's tuner is 2' from the insulated backstay on top of the aft
cabin. Wanna see my QSL card from Osaka, Japan on 15 meters? I was 5
by 6 with just the little 150 watt transmitter. Not bad, given the
awful conditions of the ionosphere these days and all the masts
suckin' up my signal from Ashley Marina......

"Ground" is a relative thing in RF. You don't even need a "ground"
ground. What you need is a slightly longer than 1/4 wavelength radial
system from the tuner laid out flat. But, alas, that's not practical
because my captain keeps bitching at me every time he trips over my
ground screen, so we compromise with a copper strap to the engine
block and my trailing wire behind the boat while at sea, creating a
giant L antenna with the tuner in the corner of the L. Man, that
works great!

Putting the tuner in the bilge, you have a problem. The "radiating
element" starts at that high voltage terminal on the other end of the
tuner. ANYTHING CONDUCTIVE anywhere near (10'?) it will become part
of the tuning problem and part of the load on the radiating element.
Any boat wiring anywhere near that radiating element WILL suck off
your signal into its light bulb loads, and shunt off your signal to
anything it's connected to.....subtracting from what goes on the air.

Nope....doesn't wash. The tuner needs to be as close to the antenna
as possible and the antenna needs to be as far away from any other
metal objects as you can get it. Unfortunately, in a boat, that's
never far enough unless you're on a ship. Go visit any Navy ship and
notice how the antenna tuners are all mounted right UNDER the bottom
of those 35' nice aluminum whips sitting on huge insulators. Lucky
steel hull owners have great ground planes. For the rest of us, hook
as many different ground paths as you can from the ground lug on the
tuner to as much metal and ground plates as you have available. The
more the better.

(Engineers note on trailing grounds - Don't put something shiny on the
trailing end to haul out the wire behind you. "Something" ate my beer
can and half the trailing wire!)



On Fri, 23 Jan 2004 17:22:54 GMT, Gary Schafer
wrote:

An antenna tuner does not belong on the bridge! That is the worst
place for it.

The first thing I would do is to get that tech back and make him put
the tuner where it belongs, In the bilge! Right next to the ground.
You must have a very short ground lead. The length you have now comes
no where near being ground. You might get away with it on 2 Mhz but
not anything higher.

Mount the antenna down near the deck if you have to. Keep the antenna
as far away from other electronics AND wiring as you can.

It will not hurt to have a long antenna lead from the tuner to the
antenna as long as it is in the clear and away from other wires.
Remember that the antenna lead IS part of the antenna, just as much as
the whip is.

The most important thing is to have a SHORT ground lead. Right now
your ground lead is acting as part of your antenna and coupling into
all the other wiring. Especially your LINK system with the leads right
next to the ground lead. (which in your case is part of the antenna)!!

Once you have the proper ground then it is a much easier job to start
to eliminate RF being picked up directly from the antenna. The problem
now is that it is probably being picked up from both the ground lead
and the antenna. It is very difficult to deal with both.

Once a lead leaves the ground connection (connection at the dynaplate)
then the rest becomes antenna. It doesn't matter what side of the
tuner it is on.

Remember "if it isn't ground then it is antenna".

Regards
Gary


On Fri, 23 Jan 2004 08:05:10 -0600, "Keith"
wrote:

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays
clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as
is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel
and
electronics, etc.

2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate.
I
plan to add some more foil and connect the fuel tanks and run some
radials
down there as well. Lets see: the run from the radio to the antenna
tuner is
about 25', and the run from that one to the dynaplate is about 10'.

No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do
rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

No, my hand doesn't burn when transmitting! ;-)

Yes, I believe the VHF cable needs replacing. It's old and probably
cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same
chase.
I don't think I connected the sheild to ground though... I'll fix that.


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!

It will probably make a big difference if you have a crappy ground to
start with.
If you have a half decent ground you should not notice any difference.

A long trailing wire in the sea is nothing more than a false ego trip.
After the first couple of feet in the water the rest does nothing for
the radio. It may make the operator feel more powerful though.

Regards
Gary

On Sat, 24 Jan 2004 11:31:09 -0500, "Doug Dotson"
wrote:

I tried the trailing wire bit last spring on the way back across the
GS. Didn't seem to make any difference over just having the
ground connected to a thru-hull. I guess it depends upon the
specifc installation.

Doug, k3qt
s/v Callista

"Larry W4CSC" wrote in message
...
(sigh) Where DO they get these crazy ideas?......

Lionheart's tuner is 2' from the insulated backstay on top of the aft
cabin. Wanna see my QSL card from Osaka, Japan on 15 meters? I was 5
by 6 with just the little 150 watt transmitter. Not bad, given the
awful conditions of the ionosphere these days and all the masts
suckin' up my signal from Ashley Marina......

"Ground" is a relative thing in RF. You don't even need a "ground"
ground. What you need is a slightly longer than 1/4 wavelength radial
system from the tuner laid out flat. But, alas, that's not practical
because my captain keeps bitching at me every time he trips over my
ground screen, so we compromise with a copper strap to the engine
block and my trailing wire behind the boat while at sea, creating a
giant L antenna with the tuner in the corner of the L. Man, that
works great!

Putting the tuner in the bilge, you have a problem. The "radiating
element" starts at that high voltage terminal on the other end of the
tuner. ANYTHING CONDUCTIVE anywhere near (10'?) it will become part
of the tuning problem and part of the load on the radiating element.
Any boat wiring anywhere near that radiating element WILL suck off
your signal into its light bulb loads, and shunt off your signal to
anything it's connected to.....subtracting from what goes on the air.

Nope....doesn't wash. The tuner needs to be as close to the antenna
as possible and the antenna needs to be as far away from any other
metal objects as you can get it. Unfortunately, in a boat, that's
never far enough unless you're on a ship. Go visit any Navy ship and
notice how the antenna tuners are all mounted right UNDER the bottom
of those 35' nice aluminum whips sitting on huge insulators. Lucky
steel hull owners have great ground planes. For the rest of us, hook
as many different ground paths as you can from the ground lug on the
tuner to as much metal and ground plates as you have available. The
more the better.

(Engineers note on trailing grounds - Don't put something shiny on the
trailing end to haul out the wire behind you. "Something" ate my beer
can and half the trailing wire!)



On Fri, 23 Jan 2004 17:22:54 GMT, Gary Schafer
wrote:

An antenna tuner does not belong on the bridge! That is the worst
place for it.

The first thing I would do is to get that tech back and make him put
the tuner where it belongs, In the bilge! Right next to the ground.
You must have a very short ground lead. The length you have now comes
no where near being ground. You might get away with it on 2 Mhz but
not anything higher.

Mount the antenna down near the deck if you have to. Keep the antenna
as far away from other electronics AND wiring as you can.

It will not hurt to have a long antenna lead from the tuner to the
antenna as long as it is in the clear and away from other wires.
Remember that the antenna lead IS part of the antenna, just as much as
the whip is.

The most important thing is to have a SHORT ground lead. Right now
your ground lead is acting as part of your antenna and coupling into
all the other wiring. Especially your LINK system with the leads right
next to the ground lead. (which in your case is part of the antenna)!!

Once you have the proper ground then it is a much easier job to start
to eliminate RF being picked up directly from the antenna. The problem
now is that it is probably being picked up from both the ground lead
and the antenna. It is very difficult to deal with both.

Once a lead leaves the ground connection (connection at the dynaplate)
then the rest becomes antenna. It doesn't matter what side of the
tuner it is on.

Remember "if it isn't ground then it is antenna".

Regards
Gary


On Fri, 23 Jan 2004 08:05:10 -0600, "Keith"
wrote:

OK, more details on the system. Icom 802 going to the AT-140 automatic
antenna tuner. Yes, the tuner is working, you can hear the relays
clicking
when you press the "tune" button or transmit. The antenna (made by the
Digital company... I should have specified!) is on the flying bridge, as
is
the tuner. The tuner is about 3' from the antenna. The antenna is right
behind and above the pilothouse. The base is maybe 10' from the wheel
and
electronics, etc.

2" copper foil runs from the radio to the antenna tuner, and splits off
about midway and goes to the bilge, where it's connected to a dynaplate.
I
plan to add some more foil and connect the fuel tanks and run some
radials
down there as well. Lets see: the run from the radio to the antenna
tuner is
about 25', and the run from that one to the dynaplate is about 10'.

No, we didn't check the SWR. I wanted to add more foil and some ferrite
cores to see how this helps out. I wanted to do the things I can do
rather
than pay the tech all those $$$ for basically grunt work. I can call him
back out whenever.

No, my hand doesn't burn when transmitting! ;-)

Yes, I believe the VHF cable needs replacing. It's old and probably
cracked
somewhere along the line. The Link 20 DOES have the sheilded cabling as
Larry described, but the ground foil runs right alongside in the same
chase.
I don't think I connected the sheild to ground though... I'll fix that.


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!