Hello group - This is my second post regarding SSB installation

Three quick questions if I may. First, I understand that round wire is
invisible in the grounding system and flat sheet or screen copper is
required/preferable. If screen is used, what are the critical
characteristics - grid size, wire size, etc? I am concerned that the screen
is just a bunch of small round wires. Second question is related. It is
recommended to use several isolation capacitors for establishing the
connection to the engine or other DC ground to avoid a DC ground loop
between the antenna system and the radio. Once again, aren't the lead wires
to the capacitors round wire and won't they "disappear" electrically? Third,
is it important to keep the ground plane below the water level?

My current plan is to laminate the interior of the hulls (catamaran), above
and below the water line, with copper "insect screen" and tie it to the
engine ground, water tank, etc with 3" copper straps and pull it all back to
a single point at the tuner.

Opinions?

Jerry Peters

"Jerry Peters" wrote in message
...
Hello group - This is my second post regarding SSB installation

Three quick questions if I may. First, I understand that round wire is
invisible in the grounding system and flat sheet or screen copper is
required/preferable.

That is true. Copper foil is used most often.

If screen is used, what are the critical characteristics - grid size, wire
size, etc?

As far as I know it is not critical.

I am concerned that the screen is just a bunch of small round wires.

Not electrically.

Second question is related. It is
recommended to use several isolation capacitors for establishing the
connection to the engine or other DC ground to avoid a DC ground loop
between the antenna system and the radio. Once again, aren't the lead
wires
to the capacitors round wire and won't they "disappear" electrically?

Round wires don't eliminate the signal just attenuate it.

Third,
is it important to keep the ground plane below the water level?

Yes. It is intended to capacitively couple to the water.

My current plan is to laminate the interior of the hulls (catamaran),
above
and below the water line, with copper "insect screen" and tie it to the
engine ground, water tank, etc with 3" copper straps and pull it all back
to
a single point at the tuner.

Alot of work for not much gain. Just connecting the ground using foil
from the tuner and radio to a thruhull works just fine. The old methods
of running all kinds of mesh and foil has been pretty much debunked in the
past few years. There have been a few articles on the subject. One I can
recall compared 1) mesh glassed into a new boat, 2) hanging the
ground over the side, 3) trailing the ground behind the boat, 4) tying
the ground to a thruhull. All systems were connected to a switch so that
the rig could be switched between the systems quickly. Result: no system
performed any better than the others in any substantive sense both
transmitting and receiving.

Make sure the thruhull isn;t part of a bonding system.

Opinions?

Jerry Peters

"Doug Dotson" wrote in message ...
"Jerry Peters" wrote in message
...
Hello group - This is my second post regarding SSB installation

Three quick questions if I may. First, I understand that round wire is
invisible in the grounding system and flat sheet or screen copper is
required/preferable.

That is true. Copper foil is used most often.

If screen is used, what are the critical characteristics - grid size, wire
size, etc?

As far as I know it is not critical.

I am concerned that the screen is just a bunch of small round wires.

Not electrically.

Second question is related. It is
recommended to use several isolation capacitors for establishing the
connection to the engine or other DC ground to avoid a DC ground loop
between the antenna system and the radio. Once again, aren't the lead
wires
to the capacitors round wire and won't they "disappear" electrically?

Round wires don't eliminate the signal just attenuate it.

Third,
is it important to keep the ground plane below the water level?

Yes. It is intended to capacitively couple to the water.

My current plan is to laminate the interior of the hulls (catamaran),
above
and below the water line, with copper "insect screen" and tie it to the
engine ground, water tank, etc with 3" copper straps and pull it all back
to
a single point at the tuner.

Alot of work for not much gain. Just connecting the ground using foil
from the tuner and radio to a thruhull works just fine. The old methods
of running all kinds of mesh and foil has been pretty much debunked in the
past few years. There have been a few articles on the subject. One I can
recall compared 1) mesh glassed into a new boat, 2) hanging the
ground over the side, 3) trailing the ground behind the boat, 4) tying
the ground to a thruhull. All systems were connected to a switch so that
the rig could be switched between the systems quickly. Result: no system
performed any better than the others in any substantive sense both
transmitting and receiving.

Make sure the thruhull isn;t part of a bonding system.

Opinions?

Jerry Peters

Doug, could you elaborate on the point of the through hull not being part of the bonding system.
I am putting in a SSB next in week my '74 Swan 38. I have Monal water
and fuel tanks and bronze through hulls. I was planning on connecting
the tanks with a piece of mesh running through the bilge. Sounds like
you are suggesting that I would be just as well off to run a 1" foil
from the tuner to the first bronze through hull.
Thanks
John

On 8 Aug 2004 19:46:14 -0700, (John) wrote:

Sounds like
you are suggesting that I would be just as well off to run a 1" foil
from the tuner to the first bronze through hull.

============================================

On a sailboat my first choice would be run a 2 or 3 inch copper strap
to a keel bolt.

If a thruhull is part of a bonding system there will be a wire (usually
green)
connecting all the underwater metals. Just disconnect it to isolate the
thruhull you plan to use. If you can pick up multiple thruhulls that is even
better. If you have access to a keel bolt then that is good too. I use
foil because the mesh seems to corrode away much quicker.

Doug
s/v Callista

"John" wrote in message
om...
"Doug Dotson" wrote in message
...
"Jerry Peters" wrote in message
...
Hello group - This is my second post regarding SSB installation

Three quick questions if I may. First, I understand that round wire
is
invisible in the grounding system and flat sheet or screen copper is
required/preferable.

That is true. Copper foil is used most often.

If screen is used, what are the critical characteristics - grid size,
wire
size, etc?

As far as I know it is not critical.

I am concerned that the screen is just a bunch of small round wires.

Not electrically.

Second question is related. It is
recommended to use several isolation capacitors for establishing the
connection to the engine or other DC ground to avoid a DC ground loop
between the antenna system and the radio. Once again, aren't the lead
wires
to the capacitors round wire and won't they "disappear" electrically?

Round wires don't eliminate the signal just attenuate it.

Third,
is it important to keep the ground plane below the water level?

Yes. It is intended to capacitively couple to the water.

My current plan is to laminate the interior of the hulls (catamaran),
above
and below the water line, with copper "insect screen" and tie it to
the
engine ground, water tank, etc with 3" copper straps and pull it all
back
to
a single point at the tuner.

Alot of work for not much gain. Just connecting the ground using foil
from the tuner and radio to a thruhull works just fine. The old methods
of running all kinds of mesh and foil has been pretty much debunked in
the
past few years. There have been a few articles on the subject. One I can
recall compared 1) mesh glassed into a new boat, 2) hanging the
ground over the side, 3) trailing the ground behind the boat, 4) tying
the ground to a thruhull. All systems were connected to a switch so that
the rig could be switched between the systems quickly. Result: no system
performed any better than the others in any substantive sense both
transmitting and receiving.

Make sure the thruhull isn;t part of a bonding system.

Opinions?

Jerry Peters

Doug, could you elaborate on the point of the through hull not being
part of the bonding system.
I am putting in a SSB next in week my '74 Swan 38. I have Monal water
and fuel tanks and bronze through hulls. I was planning on connecting
the tanks with a piece of mesh running through the bilge. Sounds like
you are suggesting that I would be just as well off to run a 1" foil
from the tuner to the first bronze through hull.
Thanks
John

In article ,
"Jerry Peters" wrote:

Hello group - This is my second post regarding SSB installation

Three quick questions if I may. First, I understand that round wire is
invisible in the grounding system and flat sheet or screen copper is
required/preferable. If screen is used, what are the critical
characteristics - grid size, wire size, etc? I am concerned that the screen
is just a bunch of small round wires. Second question is related. It is
recommended to use several isolation capacitors for establishing the
connection to the engine or other DC ground to avoid a DC ground loop
between the antenna system and the radio. Once again, aren't the lead wires
to the capacitors round wire and won't they "disappear" electrically? Third,
is it important to keep the ground plane below the water level?

My current plan is to laminate the interior of the hulls (catamaran), above
and below the water line, with copper "insect screen" and tie it to the
engine ground, water tank, etc with 3" copper straps and pull it all back to
a single point at the tuner.

Opinions?

Jerry Peters



MF/HF Low Impedance RF Ground Systems are not that hard to understand,
if one just uses a bit of common electrical reasoning.
First, The water that your floating in is the best ground around.
Second, Coupling your Antenna Ground to that water is what we are
really talking about in these discussions.
Third, there are two ways to accomplish the above said "Coupling".
Directly connecting the Antenna Ground to the water, and capacativly
coupling the Antenna Ground, to the water. The former works really well,
but electrolysis will eat your connections Big Time. DynaPlates are your
friend. The later is what most plastic and wood vessels use to
accomplish this. Think of the water as ONE plate of the two that are
required to build a Capacitor to couple the RF to the water. Think of
the strap, screen, metal fueltanks, metal water tanks, keel metal,
ect, as the other plate of the capacitor.
Now how do we get MORE capacitance between the two plates? First, move
the two plates CLOSER together. Ie get the screen, straping, tanks,
keel, as close to the water as possible. Like right next to the hull.
Second, Add more SURFACE AREA to the plate inside the hull. More screen,
more tanks, more metal, more, more, more.
With enough coupling your Antenna Ground should be capable of good
efficency clear down in the 1.6 Mhz range. With a marginal RF Ground
your going to have to rely on 4 Mhz and above for communicating.
Your autotuner will take care of the antenna tuning, but it NEEDS a
really Good RF Ground to work PROPERLY. Autotuners have one very
LARGE failing. They CAN"T tune frequencies close to the 1/2 wave
natual resonace frequency of your antenna. Usually about 150 Khz
on each side, higher and lower. So you must design the antenna
so that the 1/2 wave point is in at a frequency that you AREN'T
EVER going to use.

end of Lectu RF Grounding on Nonmetal Hulls - Part 1


With a metal hull, this is not a problem as the whole hull is the plate,
insulated by the bottom paint from the water, and protected from
electrolysis by your zincs.

Bruce in alaska
--
add a 2 before @