ssb ground plate

[Birdseye]

yes I know that you can go out and spend lots of £ on a sintered bronze ground plate but what I would be interested in hearing is someone who has had a flash of brilliance and thought up an equally effective really cheap alternative.

 

[Bilgediver]

yes I know that you can go out and spend lots of £ on a sintered bronze ground plate but what I would be interested in hearing is someone who has had a flash of brilliance and thought up an equally effective really cheap alternative.

Keel? DOn t forget that ou also need a good conductor for the RF ground. Ships used 75 mm copper foil but a good multistrand might do such as welding wire

 

[Roberto]

About £10 of suitably cut radials from a 5-wire electric cable, loosely thrown inside the aft lockers. I have used it on mine plus a good number of other people boats.

If you do not want to measure and cut the wires then you can buy the commercial "KISS" ground for a ready made solution, though it's an identical thing with a different price tag

 

[Birdseye]

I have tried using the 3 tonnes of epoxy encased lead that hangs below the boat but I get lots of feedback into earphones and mike. My problem is that despite having all the correct bits of paper, I dont really understand aerials and propagation so I dont really know where my problem is. The set up is a backstay aerial, an auto atu a meter away from the bottom of the aerial and the keel as a ground plane about 4 meters away. The aerial insulators are very close to the top and bottom of the backstay which might also be an issue.

 

[Danbury]

Buy a steel hulled boat...

I'll get my coat...

 

[Birdseye]

Dont forget your hat as well. And that pile of rust you left behind.

 

[Gerry]

We got rid of the ground plate and installed an http://www.kiss-ssb.com/ . It's simple to install and has worked very well for us. ON our last Atlantic crossing we were frequently told that we were the loudest boat on frequency(!) and often the only boat that could act as a relay........
Cannot recommend it highly enough.

 

[rogerthebodger]

I second that and with proper paint and prep no rust.

 

[Danbury]

You might want to contact Bob at http://www.sailcom.co.uk/

I did my LRC with him... very knowledgable/helpful and I think he can supply the KISS system.

No link, just satisfied customer.

 

[Birdseye]

About £10 of suitably cut radials from a 5-wire electric cable, loosely thrown inside the aft lockers. I have used it on mine plus a good number of other people boats.

If you do not want to measure and cut the wires then you can buy the commercial "KISS" ground for a ready made solution, though it's an identical thing with a different price tag

Can you give me a few design details please. As it happens I only use the ham 80m band for chatting to friend and the 40m band occasionally so I guess I only need two radials. Is it as simple as a 1/4 wavelength wire for the mid point of both bands, strapped together and connected to the earth terminal of the ATU?

 

[William_H]

Can you give me a few design details please. As it happens I only use the ham 80m band for chatting to friend and the 40m band occasionally so I guess I only need two radials. Is it as simple as a 1/4 wavelength wire for the mid point of both bands, strapped together and connected to the earth terminal of the ATU?

The radials are one way to get the counterpoise for the HF aerial. As you suggest one wire at 1/4 wavelength for each band. 1/4 wavelength at 80 metres might be difficult to stretch out in most modest sized boats.
The other option which might be how the above radials work is to run wiring and even a foil layer inside the hull. (presumably GRP) This can act as acapacitor to the sea water. You will need a large area as the hull will be quite thick.
So I don't really know the answer. A connection to the keel is likely to be long lead causing problems. I can only suggest what I would do which is to have as much wire as possible and perhaps foil under floors and in lockers plus connection to the engine earth. You might want a large isolating capacitor here. See how you go.
The modern auto tuners will tune almost anything even without an earth counterpoise but that does not mean it will radiate effectively.
Beware if indicator lights for lighr systems start flashing when you talk. This is an indication power is hanging around not getting out. good luck olewill

 

[coopec]

Posted by William-H]
"The other option which might be how the above radials work is to run wiring and even a foil layer inside the hull. (presumably GRP) This can act as a capacitor to the sea water. You will need a large area as the hull will be quite thick"

I have read something along the same lines. The author of an article on ground plates suggested laying copper mesh over a large area of the bilge (bigger the better) and then earth it to a submerged ground plate. The author suggested that "tricked" the radio into thinking it had a large ground plate.

 

[KellysEye]

>I have read something along the same lines. The author of an article on ground plates suggested laying copper mesh over a large area of the bilge (bigger the better) and then earth it to a submerged ground plate. The author suggested that "tricked" the radio into thinking it had a large ground plate.

We knew an the crew on an American 42 foot cat. When they had it built they had copper foil built in to both hulls and thus had a strong signal. The foil was not connected to a submerged ground plate. It's not necessary on any ground unless the only ground is the submerged plate. Most boats ground the SSB radio by linking anything metal inside the boat including the engine.

>Can you give me a few design details please. As it happens I only use the ham 80m band for chatting to friend and the 40m band occasionally so I guess I only need two radials. Is it as simple as a 1/4 wavelength wire for the mid point of both bands, strapped together and connected to the earth terminal of the ATU?

If you have an ATU you don't need radials for specific frequencies. The ATU tricks the aerial into thinking it's the right length for any frequency. The aerial should be about 35 feet and makes up half any wavelength, the rest is the ground. As said steel boats are the best for strong signals because the whole hull is the ground

 

[jwilson]

Not in any way a tech expert on SSB but I usually got the job of using the thing as I did not get seasick. The boats that had the best transmission reception were those where the ground was a big thin foil plate glued to the inside of the GRP hull - better than a couple of boats with fancy external grounds - one had gold plated bits. The aeriel was always an insulated backstay.

 

[coopec]

We knew an the crew on an American 42 foot cat. When they had it built they had copper foil built in to both hulls and thus had a strong signal. The foil was not connected to a submerged ground plate. It's not necessary on any ground unless the only ground is the submerged plate. Most boats ground the SSB radio by linking anything metal inside the boat including the engine.

I am certainly no expert in this field but by linking anything metal to the engine isn't that like linking it to a ground plate? Surely any electrical charge will go through the engine, the prop shaft and the propeller? Maybe I am overlooking something?

 

[ip485]

Very receNtly installed an icom and used the kiss system connected directly to the tuner. Works superbly well and very eady - an excellent solution.

 

[geem]

Not in any way a tech expert on SSB but I usually got the job of using the thing as I did not get seasick. The boats that had the best transmission reception were those where the ground was a big thin foil plate glued to the inside of the GRP hull - better than a couple of boats with fancy external grounds - one had gold plated bits. The aeriel was always an insulated backstay.

I installed my Furuno set in 2005 to my last boat before crossing the Atlantic. I followed the Furuno installation manual. We wired 50 mm copper tape through the bilges of our cat in each hull. We grounded the keel cooler for the fridge, the rig by attachment to a cap shroud and that was about it. We used a 26 ft commercial whip antenna and had fantastic reception and transmission. We relayed for a number of boats on the crossing.

 

[Birdseye]

The radials are one way to get the counterpoise for the HF aerial. As you suggest one wire at 1/4 wavelength for each band. 1/4 wavelength at 80 metres might be difficult to stretch out in most modest sized boats.
The other option which might be how the above radials work is to run wiring and even a foil layer inside the hull. (presumably GRP) This can act as acapacitor to the sea water. You will need a large area as the hull will be quite thick.
So I don't really know the answer. A connection to the keel is likely to be long lead causing problems. I can only suggest what I would do which is to have as much wire as possible and perhaps foil under floors and in lockers plus connection to the engine earth. You might want a large isolating capacitor here. See how you go.
The modern auto tuners will tune almost anything even without an earth counterpoise but that does not mean it will radiate effectively.
Beware if indicator lights for lighr systems start flashing when you talk. This is an indication power is hanging around not getting out. good luck olewill

The auto tuner seems to be tuning OK - the problem is that the outgoing signal is weak, the incoming signal is if anything weaker and there is a large amount of feedback on transmission. As for grounds I have tried using the keel, the anode, even the boarding ladder dropped down into the sea.

 

[KellysEye]

> Surely any electrical charge will go through the engine, the prop shaft and the propeller? Maybe I am overlooking something?

The ground is the radio's earth. I'm not aware of any electrical charge through the engine etc, if there were people wouldn't link metal up.

 

[coopec]

> Surely any electrical charge will go through the engine, the prop shaft and the propeller? Maybe I am overlooking something?

The ground is the radio's earth. I'm not aware of any electrical charge through the engine etc, if there were people wouldn't link metal up.

I don't follow of your last point "I'm not aware of any electrical charge.................." Please elucidate.

Isn't the propeller like an external grounding plate so that if you connect your copper mesh/foil to the motor that is like connecting it to an external grounding plate?