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