TomS wrote:
1. Does anybody have experience on making a SSB ground system on a carbon
fibre hull?
2. Has anyone used sheets of metal (stainless stainless or copper) glued to
the inside of the hull instead of laminating copper starps to the hull?
Dynaplates or similar can not be used due to the drag that they create,
neither can they be recessed into the hull as cutting in to the hull is not
an option due to directinal fibres in the hull.
My idea is to use 4pcs of 30cm by 50cm 0,5mm thick AISI316 plates glued to
the inside of the hull as groundplane. Any ideas or experience?
In theory the hull could be my ground plane, as carbon is a pretty good
conductor, but dont know..?!
How does carbon fibre work as a dielectric? Just wondering how the
capacitive coupling would work.
Regards, and Merry Christmas to you all
TomS
Consider using lifelines and pulpits for your "ground". Insulate
them all around. The hull is an insulator, so they are likely
insulated already. Test it. Some fear electrocution if the shrouds
or mast are live, connected to the backstay / antenna element at the
masthead. You could loft an insulator on the backstay. Try it
uninsulated first, or later. A sheath of garden hose would protect
deck apes from radio burns. You could test for danger, but I suspect
you would search frequencies for a long time to find a dangerous
tickle.
Worked for me on C.B.
I doubt anyone will gaurantee much improvement in radio range by
papering the hull with tinfoil or mesh or even plate for use as an
"Earth Ground," whatever. A full length insulated antenna element in
the bilge might do well as a radio counterbalance for the "official"
antenna feed. The battery ground leads to the radio, and elsewhere
beyond the battery probably also figure as part of the antenna array.
You want counterpoise, not neccessarily a radio ground. There is
really no such thing as a long range radio ground. Consider a
metallic bootstripe, keelson or heavy aluminium foil tape bonded
just under the hull deck joint. The sea ground, keel or plate, may,
but shouldn't affect local radio noise interference. You will want
one for a lightning protection ground, and could test to see. If it
works good, couple to it with a .01 micro Farad high voltage
capacitor. More alternatives exist.
Only a properly oriented and phased antenna array will improve
propogational efficiency.
You need a low resistance connection to the sea for lightning
dissapation. Are you using a carbon fibre mast? Conductive shrouds?
Conductive elements in mast, like a VHF antenna coax, lights, wind
instruments, or better?
Reduce radio noise at it's source, usually the alternator and video
devices, even flourescent tubes and depth sounders, anything with a
processor or diode in it. You will probably never eliminate it all.
You should not consider antennae or rig without regard for lightning.
Nor should you ignore galvanic corrosion. It is only enabled when
connections exist between dissimilar parts immersed in the sea. Do
not automatically connect all metal parts.
Terry K
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