marcot
Well-Known Member
I need to ground my atu icom 130. The rudder stock or a through Hull fitting would suit? Any corrosion problems? Lookin for experiences.
Atu tuner icom 130
- Thread starter marcot
- Start date
rogerthebodger
Well-Known Member
You need a large an ares as possible but it does not need to be in direct contact with the sea water.
On a GRP boat most installations I have seen use copper foil strips positioned around the inside of the bulge.
I have a steel hull boat so my atu is grounded to the hull with no corrosion problems.
On a GRP boat most installations I have seen use copper foil strips positioned around the inside of the bulge.
I have a steel hull boat so my atu is grounded to the hull with no corrosion problems.
oldvarnish
Well-Known Member
You need a Dynaplate or a KISS
I suggest you go to this: http://info.yachtcom.co.uk/hf-antennas.php and scroll down to Dynaplate and read on from there
I suggest you go to this: http://info.yachtcom.co.uk/hf-antennas.php and scroll down to Dynaplate and read on from there
MM5AHO
Well-Known Member
You can do this at very low cost using the counterpoise method.
I have 5 wires from the "earth" terminal of my ATU. They run from stern where ATU is, to the bow. One follows roughly the centre line and the other two either side. The outermost wires are at about sealevel, and the innermost about halfway between the outermost and the central one. This means a sort of fish outline. Start at a point, finish at a point and widest spacing is amidships.
Cost? nothing, I had some old plastic insulated cable lying about, but if I purchased something like this http://www.screwfix.com/p/conduit-wiring-cable-6491x-1-core-1-5mm-x-100m-brown/63636 for £20, then I'd have enough to do the job twice!
Advantages?
Works very well. (international contacts. I tested this against alternatives while in contact with a boat in USA, and signal was better than some others, no worse than any)
Low cost
Easily replaced
No through hull holes like a Dyna plate requires.
Nothing to go wrong.
Disadvantages?
More wire in the hull to get tangled.
I have 5 wires from the "earth" terminal of my ATU. They run from stern where ATU is, to the bow. One follows roughly the centre line and the other two either side. The outermost wires are at about sealevel, and the innermost about halfway between the outermost and the central one. This means a sort of fish outline. Start at a point, finish at a point and widest spacing is amidships.
Cost? nothing, I had some old plastic insulated cable lying about, but if I purchased something like this http://www.screwfix.com/p/conduit-wiring-cable-6491x-1-core-1-5mm-x-100m-brown/63636 for £20, then I'd have enough to do the job twice!
Advantages?
Works very well. (international contacts. I tested this against alternatives while in contact with a boat in USA, and signal was better than some others, no worse than any)
Low cost
Easily replaced
No through hull holes like a Dyna plate requires.
Nothing to go wrong.
Disadvantages?
More wire in the hull to get tangled.
KellysEye
Well-Known Member
The ground makes up half the aerial so it's very important. We had a steel boat which has one of the strongest signals an American cat had the same with copper foil in both hulls. Ground plates can't make up half the aerial. Also to connect the ATU to the aerial use copper foil until the exit point in the hull, we then used a small length of copper wire clamped above the insulator. Never touch the wire above the insulator when transmitting you will cook your hand from inside out, find somebody who smokes and you can light a cigarette on it.
oldvarnish
Well-Known Member
MM5AHO is right about counterpoises. I mentioned the KISS (above) which is the expensive way of doing it, but if you're uncertain about the various lengths etc then you might think it was worth the money.
But, yes, you can it on the cheap quite easily.
But, yes, you can it on the cheap quite easily.
Birdseye
Well-Known Member
This is a complete juju area! With a degree in physics and a ham radio licence I started off taking the issue of counterpoise design seriously. I've tried the lot including a few non conventional ones like connecting to the stainless wire lifelines running round the deck, to the rudder stock, the boat anode, a dynaplate, a lead keel . I could go on but wont.
I found sod all difference between any of them .
Try what anyone suggests. You can make an interesting pastime of it.
Currently I'm using a lead keel
I found sod all difference between any of them .
Try what anyone suggests. You can make an interesting pastime of it.
Currently I'm using a lead keel
duncan99210
Well-Known Member
Never actually fitted one myself but when talking to a local guru on the topic I asked him about using the cast iron keel. His response was along the lines of 'that'd do'. So if I ever do find the money to fit an SSB, that's what I'll do.
oldvarnish
Well-Known Member
I wonder if a lead keel would make a ground if it was epoxied, or would it become a counterpoise?
William_H
Well-Known Member
The difference does not matter. The epoxy will insulate the keel from the salt water (maybe) but the2 will form a capcitor which will carry the radio frequency AC through anyway.
Which brings me to the question of the OP regarding electrolysis corrosion. You can connect to any underwater metal part via a capacitor to isolate DC. The capacitor carries a lot of current on transmit so should be in the form of 10 or so ceramic capacitors in parallel typically 10000nf or .001 uf in a high voltage type like 600v. (still very cheap)
I had a friend who fitted an SSB to a Beneteau. He obviously took short cut or failed to provide the earthing (couterpoise)
Performance was hopeless and on transmit all the switch indicator lights flashed to his voice. Indicating power not getting out. Do try to get a decent earth/ counterpoise good luck olewill
