Icom 802 troubleshooting

[Keith]

Well, I had a tech come out and check out my system. M-802 with the
automatic antenna tuner. He said that the radio is only putting out about 50
watts, and should be putting out 100-150 watts, so he thinks something is
wrong with the radio (new, right outta the box...)

He also mentioned that the automatic antenna tuner should be closer to the
ground plate. In the Icom manuals, they said to mount it as close to the
antenna as possible, so it's on the flying bridge, and the conductor from
the tuner to the antenna is about 3'. I can move it about halfway between
the antenna and the ground plate in the engine room. Who's right?

The final thing is that I ran a 2" ground foil strip from the radio to the
ground plate as well, as required by the ICOM manual... he said this isn't
necessary and should be disconnected. I'm really confused now.

Help!

At this point, I'm going to take the radio in to the dealer and have it
checked out and anything corrected as needed, then see how things work
before I start moving the tuner around.

 

[Bruce in Alaska]

Well, I had a tech come out and check out my system. M-802 with the
automatic antenna tuner. He said that the radio is only putting out about 50
watts, and should be putting out 100-150 watts, so he thinks something is
wrong with the radio (new, right outta the box...)

He also mentioned that the automatic antenna tuner should be closer to the
ground plate. In the Icom manuals, they said to mount it as close to the
antenna as possible, so it's on the flying bridge, and the conductor from
the tuner to the antenna is about 3'. I can move it about halfway between
the antenna and the ground plate in the engine room. Who's right?

The final thing is that I ran a 2" ground foil strip from the radio to the
ground plate as well, as required by the ICOM manual... he said this isn't
necessary and should be disconnected. I'm really confused now.

Help!

At this point, I'm going to take the radio in to the dealer and have it
checked out and anything corrected as needed, then see how things work
before I start moving the tuner around.

Hello Keith,


I don't know the guy you hired to do your HF Radio work, but from the
sounds of things, he isn't one of the greatest Tech's to walk down the
dock. First thing, is to transmit into a Dummy Load, and see if the
radio is capable of putting out it's rated power, into a perfect antenna.
If yes, the problem isn't in the radio. If no, then the radio needs to
be realigned. (tuned) Second, understand that any SSB Radio maybe
transmitting rated power, and it doesn't nessesarily show up on a
non-peak reading Wattmeter. There are many reasons to have the
autotuner mounted at this polace or that place. Most are related to
what type of RF Ground System your vessel has. From a strictly RF
standopoint, closer to the Ground Plate is better, and 2" copper foil
is minimal for any connection to a RF Ground System. what is the length
of the copper foil in feet? The longer the foil, the worse the ground
impedance will be, and the harder the tuner will have to work to tune
the antenna. You don't tell us anything about the vessel construction,
RF Ground System, or antenna system. Knoing these would be critical
in advising you on your installation.
Points of interest.
1. If your foil is longer than 3 or 4 Feet, then what you are asking
that autotuner to do the almost impossible. Think it as if the tuner
wan't sitting at ground but at some point above ground and that point is
the length of the copper foil. Lets say 15 Ft, as you say it is on the
Flying Bridge, and that is say 15 Ft above Waterline. Now you
effectivly have the tuner in the middle of a diopole antenna and trying
to reconcile impedances on both antenna and ground at the same time.
BAD IDEA. The firmware in the tuner only looks at the antenna
impedance, with refernce to the Ground lug on the tuner. If the ground
lug isn't at RF Ground, then the tuner firmware gets REALLY FUNNY DATA
from it's internal sensers and it doesn't deal with funny data well.
2. If the tuner is moved to a place, say 3 ft from the RF Ground, then
you must add wire to the antenna, and that wire becomes part of the
antenna, and therefore gets tuned by the tuner. This is a GOOD THING,
if people, or Ground don't come to close to it while you are
transmitting. By adding wire (length) to the antenna you are effectivly
lowering the frequency that the tuner will tune. This again is a GOOD
THING, on a plastic or wood vessel.
3. As Larry and Jim have stated, check and BE SURE, that the radio is
in TUNER MODE, and not THRU MODE. If your in THRU MODE, the tuner isn't
even going look at your antenna, let alone try and tune it.


More information!


Bruce in alaska

 

[Keith]

OK, let's see if I can give feedback to all of your notes.

Yes, the radio is set to "tune", and on full power. I will double check to
make sure the tech didn't change either of the settings. I do not know what
the SWR's were. The bad part was that I had been trying to hook up with this
guy for awhile... and I wasn't here when he did the checks.

When I hit "tune", I sure don't hear any clicks or any other evidence that
it's doing anything. The control cable was the one thing I DIDN'T do myself,
so I'm beginning to suspect that as Larry pointed out. I remember that topic
on here before. The little pins were so tiny I couldn't hardly see them much
less solder them! I think I'll work on this as Larry suggests.

The Antenna is a Digital fiberglass... don't remember the exact length, but
what the folks around here recommended... The boat is fiberglass, a Krogen
42. The 2" copper foil runs about 12-15' from the tuner on the flying bridge
down to a big Wunderbar (sp?). The bar is a scintered bronze plate, about
24" x 6" or so. Nothing else is connected or grounded to this, except that I
also have a 2" foil strip that runs to the radio and connects to the ground
on the back, as shown in in ICOM installation manual.

I think I'm going to redo the control cable as Larry suggests, and go from
there.

 

[Gary Schafer]

The ground plate that you have should provide a good ground for the
tuner but you need to move the tuner to within a couple of feet of the
ground plate.
Run your antenna lead down to the tuner. As Bruce said "it will become
part of the antenna".

Trying to use a 15 foot 2" copper strap as a ground lead will not work
well on any frequency. It is much too long and has too much
inductance.

Your antenna has an impedance of only a few ohms on some frequencies.
Your 15 foot ground lead can have an impedance of many times that
depending on the frequency being used. The power gets divided between
your antenna feed impedance and the ground impedance. If the ground
impedance is equal to the antenna impedance, your power is divided
equally between the two. 1/2 of the power is dissipated in the ground
lead and not the antenna. If the ground lead impedance is higher than
the antenna impedance then most of the power goes to the ground lead
and not the antenna.

With the long ground lead that you have you are going to get lots of
RF that gets into wires that you don't want it to. Some of it can make
its way back into the radio, power leads etc. and partially shut down
the radio.

You may have other problems with the radio or system also but you
surly have a too long ground lead problem.

Regards
Gary

 

[Gary Schafer]

Why do you say that?
The lead that goes from the antenna tuner to the antenna becomes just
as much a part of the antenna as the rest of the antenna wire.

It is much more important to have a low inductance (short) ground
lead.

Regards
Gary

 

[Gary Schafer]

Why does "the tuner need to be as close to the antenna as possible"?
The antenna lead is always part of the antenna. If the tuner is far
away from the ground the ground is part of the antenna which is
unwanted.

It doesn't matter how long the lead from the tuner to the antenna is
but it does matter how long the ground lead is.

By the way, most AM broadcast stations use 120 radials not 36. And
they are DIRECTLY under the antenna tuner! Very short ground lead.
Hint, Hint.

Trailing a 120 foot wire behind the boat is like soldering a 120 foot
long piece of wire to a sheet of copper a mile or so square, to try
and make a lower resistance connection to the copper.

A small plate a few inches into the sea water will provide as low an
impedance as you are going to get. Sea water is a much better
conductor providing a much lower inductance than a long piece of wire
ever will.

The important thing is to have the lead between your water connection
as short and as large as possible to keep its inductance down.

Regards
Gary

 

[Keith]

The antenna base is about 3' away from the tuner at it's present location,
on the flying bridge. They are basically at the same level. The antenna lead
exits the locker, then runs perpendicular about 2' to the antenna hookup.

Going to tackle the problems one at a time. Turns out that the early 802's
had manufacturing problems, and won't transmit at a strong power level. I
have one of these, and am sending it back to the factory for warranty
repair. That's what I get for being an early adopter! Next, I really suspect
the control cable, so will double check and verify that.

The tuner placement seems to be anything but a concensus. I hate to move the
thing, but if all else fails, that will be the final change. I can place it
in a locker about halfway between the antenna and ground plate. In that
position, the ground foil would have to go about 5' to the ground plate. The
other place would be right in the engine room on the bulkhead, about 2' to
the ground plate, but I worry more about heat, etc. in there. Will keep
everyone posted, and thanks for the help!

 

[Gary Schafer]

You don't suppose they are trying to sell ground foil do you? :>)

Ask Bruce about ground planes on fly bridges. :>)

Regards
Gary

 

[Gary Schafer]

What about that long ground lead. It acts as an antenna too. If the
ground lead is long so does the coax and control cable going to the
tuner act as part of the antenna. That will surly couple RF into
unwanted places. Besides making the whole system inefficient.

Regards
Gary

 

[Bruce in Alaska]

Also read Gordon West's excellent primer on radio gound planes for
boats. It comes packed with the West Marine 2" copper foil gound kit,
which by the way comes in 25' AND 50' lengths. (That may say
something about the length of gound leads right there.) He points out
that the tuner is mounted next to the antenna on the flybridge of
power boats, and at the base of the antenna (backstay) of sailboats.

If only "Old Gordie" would go out and do some realtime RF Radiation
Studies on what he espouses in his writings. The antenna needs to be
as close to the RF Ground as practicable. The closer the better.
Also remember "Old Gordie" SELLS that Copper Strap to you along with his
book.

Bruce in alaska

 

[Gary Schafer]

I haven't read everything that Gordon West has written. But some of
the stuff, especially the comparisons he makes between systems, leaves
a little to be desired.

If he says "we no longer need huge amounts of ground foil etc. because
of modern tuners", what does that tell you? That is like saying "my
radio puts out a good signal". Compared to what?

Modern tuners don't help the ground situation one bit. They haven't
changed the laws of physics. The only thing a modern tuner does is let
you get away with a poor ground system easier than the old manual
tuners. Much less work involved to get the radio to operate. Not that
it operates any better though.

Just look at the quality of some of the SGC radios. Is it any wonder
their manuals are a little off.

I have seen countless manufacturers with very poor antenna system
installation advice.

Some people have finally realized that a good connection to the sea
water is an excellent ground. Gordon West Being among them.

Now if only people would come to realize the importance of SHORT
ground leads.

Regards
Gary

 

[Bruce in Alaska]

A valid point but Gordon West also states that with the modern
couplers/tuners, we no longer need to run huge amounts of ground foil
and to link EVERY thru-hull to have a good ground plane. It used to
be that a MINIMUM of 100 sq. ft. of counterpoise was recommended.
He's a ham who writes books and magazine articles offering advice on
the best way to install your HF radio system. I don't think he'd risk
his rep telling you to install an inferior ground plane just to sell
some foil. And I don't think SGC has a monetary interest in telling
us to mount the coupler as close to the base of the antenna as
practical. In any case, I've istalled my system and others this way,
all with great success. Regards, Mark

Old Gordie, doesn't have a clue about how the firmware in "Modern
Autotuners", works, and shows his ingnorence in his writing such drivel.
The requirement for a "Solid Low Impeadance RF Ground System" doesn't
change just because you have a fancy Autotuner, instead of a clunky
old Fixed Channel Tuner, of years gone by. The only change is that
you, as a Vessel Owner, can do your own installations instead of hiring
a "Competant Marine Radioman" to do a quality job for you. This allows
you to make all the "Stupid and unintellegent" mistakes that folks with
years of experience made back on their first installation. My first
question was ALWAYS, "Do you want it to WORK, or do you want it to LOOK
GOOD?" SGC couldn't design their way out of a "Wet Paper Bag" and they
didn't do any of the "Original Design Work" on any of the Autotuner
Products. ANY THAT IS A FACT! How do you determine "great suscess"?
Like I have posted before, just making a "Radio Contact" when the band
is wide open doesn't prove anything. A "Wet Noodle" will work when the
band is open. We used to do that by calling KMI from Puget Sound all
the time, and "It don't mean Squat" Make a contact when the band is
noisy and marginal, or in the middle of a Big Storm, when your more
likly to really need to communicate, then maybe you got something.
See in the Non-commecial Maritime Radio World, you actually use the HF
Radio very little and actually make contact even less. In the Commercial
Maritime Radio World, these guys are using that radio 4 or more times a
day, every day, and if they don't get a contact, they move frequency
untill they do make contact. When they had Radio Operators, it was
considerable more contact per ship per day than that. If they had
marginal Antenna Systems and RF Grounds, they are back "Bitching" to the
Istalling Radioman, after the first voyage. Been there, had that happen!

Bruce in alaska

 

[Gary Schafer]

"SGC couldn't design their way out of a "Wet Paper Bag" and they
didn't do any of the "Original Design Work" on any of the Autotuner
Products. ANY THAT IS A FACT!"

Ok, I get it. No need to bust a blood vessel over this. The SGC
radios are known far and wide as being junk. No argument there. The
SGC tuners however, DO have a good rep, no matter who designed them.
(BTW, Honda didn't do the "original design work" on the automobile
either, yet they make a quality product.) But for the sake of your
argument, we'll dismiss SGC as a player in the coupler/tuner market.
Here's ICOM's take on mounting automatic antenna tuners on sail and
power boats. http://www.icomamerica.com/downloads/ssb_book/chptr7.pdf
Have a nice day. Mark

One reason you may see this kind of thing from manufacturers is that
is what all the rest are professing. There may be a fear that if they
tell you the proper way to do it you may not buy their radio because
it is more complicated than the competition. They really make it sound
simple and uncomplicated don't they.

Don't believe everything you read. Look for some facts to back it up.

Regards
Gary

 

[Gary Schafer]

You bring up a good point. Remember the guys that have a 12 to 15 foot
ground lead from their tuner up on the fly bridge? It just so happens
that around 16 feet is a quarter wave on 20 meters.

Now if you have one end of that 16 foot ground strap connected to the
tuner and the other end connected to a ground below, guess what ?
You have a complete open ground circuit at the tuner! That ground
strap does no good at all. Connected or disconnected at the tuner it
will make no difference.

As a matter of fact if you unhook it at the ground end (opposite the
tuner) it will be much more effective. It will then act as a quarter
wave length radial giving you some counterpoise for the tuner.

Regards
Gary

 

[Bruce Gordon]

Sorry guys i forgot 1 thing in my last lunatic rant.
If a perfect ground is exactly 1/4 wavelength away from the tuner
what does it look like ??

Answer infinite resistence

At one and only one frequency!!! What is the point of having an
Autotuner, or for that matter having any tuner if you only need
and use one Frequency? Your 1/4 wavelength Rant is BOGAS in
the Maritime Mobile Radio context...... Daaaaa

Bruce in alaska

--
Bruce (semiretired powderman & exFCC Field Inspector for Southeastern Alaska)
add a <2> before @
Bruce Gordon * Debora Gordon R.N. Bruce's Trading Post
P.O. Box EXI Excursion Inlet South
Juneau, Alaska 99850 Excursion Inlet, Alaska 99850
www.btpost.net www.99850.net

 

[Bruce in Alaska]

I don't care what books you read or who wrote them and why they decide
that the rules of physics changed because he is now being paid by what
company.

The Antenna begins at the tuner
The ground (system) begins at the antenna

Do you want the antenna radiating or the ground radiating?

Do you want the antenna as long as possible? (Look at an
antenna-engineering book to get the formula for antennas, hint: one of
the many factors that are DIRECTLY proportional is the length of
antenna (bet not very many of the non-engineer type antenna experts in
here knew that )) LOL just opened up a can of worms.

You want the ground of a vertical type antenna, sloper counts as that
in my book as it is only ¼ wavelength (not really but that's what the
tuner is for, to lie to the transmission line but really it changes
the feed point reactance, anyway I wasn't an English major and anyway
again you want the ground at the tuner to be an effective counterpoise
by coupling into the seawater without radiating any of that rf. Hot
grounds anyone, that's my story and I'm sticking to it



Gordie can write I can't he better stick to writing maybe some
children's books would be better

Yep, I agree with you and Gary on these points.......


Bruce in alaska

 

[Bruce in Alaska]

"SGC couldn't design their way out of a "Wet Paper Bag" and they
didn't do any of the "Original Design Work" on any of the Autotuner
Products. ANY THAT IS A FACT!"

Ok Bruce, I get it. No need to bust a blood vessel over this. The
SGC radios are known far and wide as being junk. The SGC tuners
however, DO have a good rep, no matter who designed them. But for the
sake of your argument, we'll dismiss SGC as a player in the
coupler/tuner market. Here's ICOM's position on mounting automatic
antenna tuners on sail and powerboats.
http://www.icomamerica.com/downloads/ssb_book/chptr7.pdf
Have a nice day. Mark

Just beacuse you read it in print from an OEM still doesn't
make it TRUTH. The guy who wrote that stuff, obviously never
had to install a system and do Proof of Performance Tests.
It's the RF Ground that is the MOST important part of any
Marine Radio Installation! Anything conductive will radiate
RF into the ether. The Best Antenna in the world will not
compensate for a POOR Rf Ground. The WORST Antenna in the world
will communicate, if it is working against a GREAT Rf Ground.

I have always believed that an Engineer should be allowed to
design anything, untill he/she has had five years experience as a
Field Service Tech in the same in Industry. This why we get
cars that you have to pull the engine to change sparkplugs,
and just plain Dumb Designs. I guess it also should be true
in the Documentation Writing Business as well.

Bruce in alaska