I would like to know a good way to position a fix-mounted VHF radio
(and its antenna), a small fishfinder (with a LCD screen), and a small
handheld GPS device (with or without an antenna) in a 18-ft center
console that has a T-top.

I have a couple questions on this issue:

- According to a boater book, I am supposed to mount the antenna for
the VHF radio at least 3 feet from another antenna or an metallic
object. I am planning to mount the radio antenna on the frame of the
T-top. Yes, I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top. But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object. Can I safely ignore this restriction? I can see that
many other center consoles also have their antenna mounted right on the
T-top. I am wondering what's the "metallic object" that the book was
referring to.

- I am under the impression that I need to keep the VHF radio unit at
least 3-ft (or 1 meter) away from the compass in order to prevent the
radio from messing up the compass. Because the compass is already
installed on the dash of the console, and the console is not that big,
I guess the only way to use a fix-mounted VHF radio in my boat is to
mount it underneat the T-top. This is OK. My question is whether we
have a similar restriction on mounting a handheld GPS device and a
fishfinder near the VHF-radio or the compass. Will the VHF radio cause
problem to the fishfinder and the GPS device? Will the fishfinder or
the GPS device cause problem to the compass? How far should I keep
them separated?

- How's about the other instruments on the dash (tachometer, motor
temp meter, battery volt meter)? Will they be affected by the
fishfinder and the GPS device?

- I am planning to use a 3-ft 3dB steel whip as the antenna of the VHF
radio. It is supposed to be pointing straight up in use. Can I folder
it down when it is not in use?

Thanks in advance for any info.

Jay Chan

On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.

That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object.

Not a problem since the metal is under the antenna. What you need to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Wayne.B wrote:
On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.

That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object.

Not a problem since the metal is under the antenna. What you need to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Thanks for the clarification. This means I should have no problem
attaching a radio antenna on the frame of the T-top as long as I point
the antenna away from the metal frame of the T-top. Good to know this.

Jay Chan

Harry Krause wrote:
wrote:
Wayne.B wrote:
On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.
That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object.
Not a problem since the metal is under the antenna. What you need to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Thanks for the clarification. This means I should have no problem
attaching a radio antenna on the frame of the T-top as long as I point
the antenna away from the metal frame of the T-top. Good to know this.

Jay Chan

Jay, you really are obsessing a bit too much about all of this.
Relax.

Sorry if I seem to act like a bit obsessive.

I have a list of boat improvement tasks waiting for me to do as soon as
the weather becomes warm. When the weather is warm, I want to spend
all my time to get the boat in a good shape, then I can launch the boat
and start enjoying boating and fishing -- the sooner, the better.
Therefore, I need to gather as much info as possible ahead of time to
avoid any delay. And now is the best time to get all the questions
answered.

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

Jay Chan

On 13 Jan 2006 10:10:18 -0800, "
wrote:

Harry Krause wrote:
wrote:
Wayne.B wrote:
On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.
That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object.
Not a problem since the metal is under the antenna. What you need to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Thanks for the clarification. This means I should have no problem
attaching a radio antenna on the frame of the T-top as long as I point
the antenna away from the metal frame of the T-top. Good to know this.

Jay Chan

Jay, you really are obsessing a bit too much about all of this.
Relax.

Sorry if I seem to act like a bit obsessive.

I have a list of boat improvement tasks waiting for me to do as soon as
the weather becomes warm. When the weather is warm, I want to spend
all my time to get the boat in a good shape, then I can launch the boat
and start enjoying boating and fishing -- the sooner, the better.
Therefore, I need to gather as much info as possible ahead of time to
avoid any delay. And now is the best time to get all the questions
answered.

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

Jay Chan

FWIW, Jay, my compass is within a foot of my radio, GPS, and fishfinder.
Haven't had a problem with any of them.

If you look at the post 'trolling.jpg' in a.b.p.s.o., you'll see my
compass. All the rest is mounted in the helm right below the top.
--
John H

"All decisions are the result of binary thinking."

On 13 Jan 2006 10:10:18 -0800, "
wrote:

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

The VHF radio will have a magnet in the speaker and should be kept
well away from the compass if possible. The fish finder is probably
less critical but you should test it before mounting by placing it
near the compass and watching to see if the compass heading changes.

JohnH wrote:
On 13 Jan 2006 10:10:18 -0800, "
wrote:

Harry Krause wrote:
wrote:
Wayne.B wrote:
On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.
That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object.
Not a problem since the metal is under the antenna. What you need to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Thanks for the clarification. This means I should have no problem
attaching a radio antenna on the frame of the T-top as long as I point
the antenna away from the metal frame of the T-top. Good to know this.

Jay Chan

Jay, you really are obsessing a bit too much about all of this.
Relax.

Sorry if I seem to act like a bit obsessive.

I have a list of boat improvement tasks waiting for me to do as soon as
the weather becomes warm. When the weather is warm, I want to spend
all my time to get the boat in a good shape, then I can launch the boat
and start enjoying boating and fishing -- the sooner, the better.
Therefore, I need to gather as much info as possible ahead of time to
avoid any delay. And now is the best time to get all the questions
answered.

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

Jay Chan

FWIW, Jay, my compass is within a foot of my radio, GPS, and fishfinder.
Haven't had a problem with any of them.

If you look at the post 'trolling.jpg' in a.b.p.s.o., you'll see my
compass. All the rest is mounted in the helm right below the top.
--
John H

"All decisions are the result of binary thinking."

Seem like the conclusion is "Keep the radio at least 3-ft away from the
compass; but there is always exception."

For me, I will likely mount the radio right under the T-top. This is
not only for keeping away from the compass, but also for leaving room
on the dash for a fishfinder and a GPS device (both cannot be
surface-mounted and must be placed on top of the dash near the compass
that is also on the dash).

Jay Chan

Wayne.B wrote:
On 13 Jan 2006 10:10:18 -0800, "
wrote:

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

The VHF radio will have a magnet in the speaker and should be kept
well away from the compass if possible. The fish finder is probably
less critical but you should test it before mounting by placing it
near the compass and watching to see if the compass heading changes.

Thanks for explaining the reason why I need to keep the radio away from
the compass. You are right; the magnet inside the speaker of the radio
will likely cause problem to the compass. On the other hand, the
fishfinder and the GPS device should not have any magnet inside.
Therefore, I have a feeling that I should be able to mount them near
the compass. Great! Now, I don't need to worry about how to mount
those devices in my boat.

One thing new that I read from Shakespeare-marine web site is that I
must keep the VHF radio at least 3-ft away from the VHF antenna.
Because I will mount the VHF radio right underneat the T-top and I will
mount the VHF antenna also onto the T-top, I will have to mount them
each in either side of the T-top. This means I need to keep the
following rules in mind when I position all the devices in my boat:
- Keep a VHF radio at least 3-ft away from a compass.
- Keep the VHF radio at least 3-ft away from a VHF antenna.
- Keep the VHF antenna at least 3-ft away from a GPS antenna.
- Test all the devices before mounting them permanently.

OK, this is easy enough.

Jay Chan

wrote in message
oups.com...
JohnH wrote:
On 13 Jan 2006 10:10:18 -0800, "
wrote:

Harry Krause wrote:
wrote:
Wayne.B wrote:
On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.
That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic
object.
The frame of the T-top is definitely made from metal. If I mount
the
radio antenna on the T-top, I will be mounting the antenna right
on an
metallic object.
Not a problem since the metal is under the antenna. What you need
to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Thanks for the clarification. This means I should have no problem
attaching a radio antenna on the frame of the T-top as long as I
point
the antenna away from the metal frame of the T-top. Good to know
this.

Jay Chan

Jay, you really are obsessing a bit too much about all of this.
Relax.

Sorry if I seem to act like a bit obsessive.

I have a list of boat improvement tasks waiting for me to do as soon as
the weather becomes warm. When the weather is warm, I want to spend
all my time to get the boat in a good shape, then I can launch the boat
and start enjoying boating and fishing -- the sooner, the better.
Therefore, I need to gather as much info as possible ahead of time to
avoid any delay. And now is the best time to get all the questions
answered.

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

Jay Chan

FWIW, Jay, my compass is within a foot of my radio, GPS, and fishfinder.
Haven't had a problem with any of them.

If you look at the post 'trolling.jpg' in a.b.p.s.o., you'll see my
compass. All the rest is mounted in the helm right below the top.
--
John H

"All decisions are the result of binary thinking."

Seem like the conclusion is "Keep the radio at least 3-ft away from the
compass; but there is always exception."

For me, I will likely mount the radio right under the T-top. This is
not only for keeping away from the compass, but also for leaving room
on the dash for a fishfinder and a GPS device (both cannot be
surface-mounted and must be placed on top of the dash near the compass
that is also on the dash).

Jay Chan


My VHF hangs from the bottom of the dash. To the right of the helm. And a
mic clip on the side of the boat. with an 18' boat, there might not be a
lot of head clearance on the T top.

On 13 Jan 2006 20:15:36 -0800, "
wrote:

JohnH wrote:
On 13 Jan 2006 10:10:18 -0800, "
wrote:

Harry Krause wrote:
wrote:
Wayne.B wrote:
On 12 Jan 2006 19:14:19 -0800, "
wrote:

I can keep the radio antenna at least 3 feet away from the
GPS antenna by keep them in either side of the T-top.
That works.

But I don't see
how I can avoid mounting the radio antenna near an metallic object.
The frame of the T-top is definitely made from metal. If I mount the
radio antenna on the T-top, I will be mounting the antenna right on an
metallic object.
Not a problem since the metal is under the antenna. What you need to
avoid is metal at the same height or above the antenna. In reality
these rules are broken all the time with only minimal impact on
performance. They are good guidelines however.

Thanks for the clarification. This means I should have no problem
attaching a radio antenna on the frame of the T-top as long as I point
the antenna away from the metal frame of the T-top. Good to know this.

Jay Chan

Jay, you really are obsessing a bit too much about all of this.
Relax.

Sorry if I seem to act like a bit obsessive.

I have a list of boat improvement tasks waiting for me to do as soon as
the weather becomes warm. When the weather is warm, I want to spend
all my time to get the boat in a good shape, then I can launch the boat
and start enjoying boating and fishing -- the sooner, the better.
Therefore, I need to gather as much info as possible ahead of time to
avoid any delay. And now is the best time to get all the questions
answered.

What is your opinion about positioning fishfinder/GPS near a compass or
a VHF radio?

Jay Chan

FWIW, Jay, my compass is within a foot of my radio, GPS, and fishfinder.
Haven't had a problem with any of them.

If you look at the post 'trolling.jpg' in a.b.p.s.o., you'll see my
compass. All the rest is mounted in the helm right below the top.
--
John H

"All decisions are the result of binary thinking."

Seem like the conclusion is "Keep the radio at least 3-ft away from the
compass; but there is always exception."

For me, I will likely mount the radio right under the T-top. This is
not only for keeping away from the compass, but also for leaving room
on the dash for a fishfinder and a GPS device (both cannot be
surface-mounted and must be placed on top of the dash near the compass
that is also on the dash).

Jay Chan

If I had a T-top that would support a radio, that's where the radio would
go!
--
John H

"Have a **spectacular** day!!