New SSB install - ground-strap via diesel tank?

[Idylles15.5]

I have a massive iron keel on my Idylle15.5. Its not encapsulated, so how well would that dissipate a lightning strike? Thats what I'm asking I guess. I tapped the top of one of my keel bolts and then attached my copper tape to it with another bolt threaded in. I just figured what could be better then a 10 thousand pound lump of iron in the water? I don't know? any ideas?

[Idylles15.5]

I also attached my braid strap from my standing rigging in this manner.

[ka4wja]

Phil,
I just saw your thread here....and by happenstance I've been working on some detailed info regarding Proper HF-SSB Radio Installation Tips/Techniques!

Have a look at this addendum here...
http://www.cruisersforum.com/forums/...ml#post2590481

And, this new thread...
http://www.cruisersforum.com/forums/...tc-198305.html

I think they will help you.



As for specifics...

Please never use "braid" for RF....and especially not on a boat....use copper strap or even regular old wire...but not "braid"...please... Not even "tinned-copper braid"...nor even SS braid...please..
I've heard of people using SS strap, but copper is a lot easier to bend / conform to a shape and connect to...as well as easier to work with and cheaper, too...
(in many decades of RF, I've never seen braid used in high RF environs that worked for more than a few weeks....and even seen it melted in tank circuits! and those have never been near sea water!)
GEORGIA COPPER - Comparison of Braid, Strap, Wire
Braid in coax (or even stranded wire) is protected from most of the issues of constant making/breaking contact in the many wires of the braid...but bare braid is problematic in these types of installations, and is not recommended by any RF engineers I've ever met...
But, of course, the choice is yours!


And, when connecting the copper strap to SS, you can sue some conductive grease (like Penatrox-A) or other water-resistant grease / sealant, thereby reducing corrosion issues...

And, although I think you're over-thinking this....Other than not using "braid", and using copper strap, your plan is not only acceptable, but tying in both your SS tank and the structure of your arch/davits/etc., is a very good approach! (maybe a bit over-kill, but a nice idea...and btw, you may find that the area of the tank and all the arch/davit structure provide all the antenna ground that you need, as by the time you've run the 14'+ to the thru-hull, quite a bit of the antenna currents may already be taken care of by the large surface area of the tank and all the arch/davit structure...

(but, fyi....I recommend running a strap directly to the thru-hull, and another to the tanks....and any wire or strap the short distance to the arch/davit structure....it might seem like a waste, and it might be...but, it gives redundancy of connections...)

Georgia Copper - COPPER GROUND STRAP for GROUNDING AND BONDING

GEORGIA COPPER - Copper ground strap

GEORGIA COPPER - Copper ground strap

GEORGIA COPPER - Comparison of Braid, Strap, Wire


As for lightning coming hitting the mast and coming down the backstay, and blowing the tuner, etc....not to worry, you should have no isues with your fuel tank...(my fuel tanks have been part of my antenna ground / RF ground for 14 years now....and I've taken a direct lightning strike, blowing out most of my electronics, and never even effected the fuel tank level gauges!! but, fyi, I do have my mast directly grounded to a keel bolt, of my 9750lb external lead keel...)


Btw, I didn't read any of the other answers, so sorry if I'm repeating something that someone else wrote...

Hope this helps.

Fair winds..

John

[Cavalier]

Originally Posted by ka4wja

Phil,
I just saw your thread here....and by happenstance I've been working on some detailed info regarding Proper HF-SSB Radio Installation Tips/Techniques!

Have a look at this addendum here...
http://www.cruisersforum.com/forums/...ml#post2590481

And, this new thread...
http://www.cruisersforum.com/forums/...tc-198305.html

I think they will help you.



As for specifics...

Please never use "braid" for RF....and especially not on a boat....use copper strap or even regular old wire...but not "braid"...please... Not even "tinned-copper braid"...nor even SS braid...please..
I've heard of people using SS strap, but copper is a lot easier to bend / conform to a shape and connect to...as well as easier to work with and cheaper, too...
(in many decades of RF, I've never seen braid used in high RF environs that worked for more than a few weeks....and even seen it melted in tank circuits! and those have never been near sea water!)
GEORGIA COPPER - Comparison of Braid, Strap, Wire
Braid in coax (or even stranded wire) is protected from most of the issues of constant making/breaking contact in the many wires of the braid...but bare braid is problematic in these types of installations, and is not recommended by any RF engineers I've ever met...
But, of course, the choice is yours!


And, when connecting the copper strap to SS, you can sue some conductive grease (like Penatrox-A) or other water-resistant grease / sealant, thereby reducing corrosion issues...

And, although I think you're over-thinking this....Other than not using "braid", and using copper strap, your plan is not only acceptable, but tying in both your SS tank and the structure of your arch/davits/etc., is a very good approach! (maybe a bit over-kill, but a nice idea...and btw, you may find that the area of the tank and all the arch/davit structure provide all the antenna ground that you need, as by the time you've run the 14'+ to the thru-hull, quite a bit of the antenna currents may already be taken care of by the large surface area of the tank and all the arch/davit structure...

(but, fyi....I recommend running a strap directly to the thru-hull, and another to the tanks....and any wire or strap the short distance to the arch/davit structure....it might seem like a waste, and it might be...but, it gives redundancy of connections...)

Georgia Copper - COPPER GROUND STRAP for GROUNDING AND BONDING

GEORGIA COPPER - Copper ground strap

GEORGIA COPPER - Copper ground strap

GEORGIA COPPER - Comparison of Braid, Strap, Wire


As for lightning coming hitting the mast and coming down the backstay, and blowing the tuner, etc....not to worry, you should have no isues with your fuel tank...(my fuel tanks have been part of my antenna ground / RF ground for 14 years now....and I've taken a direct lightning strike, blowing out most of my electronics, and never even effected the fuel tank level gauges!! but, fyi, I do have my mast directly grounded to a keel bolt, of my 9750lb external lead keel...)


Btw, I didn't read any of the other answers, so sorry if I'm repeating something that someone else wrote...

Hope this helps.

Fair winds..

John

John,

This is excellent -thank you!

Out of interest, what goes wrong with the braid? Is it its lack of environmental robustness, or is the fine-wire mesh of the braid incapable of taking some of the transient antenna currents? i.e. if the braid was encapsulated in epoxy, would that help, or does braid just degrade quickly whatever one does? On paper they seem like a good idea - but, as a highly experienced RF engineer, you recommend that I stay away from it, and I will heed your advice willingly - I just wondered what the Achilles heel was!?

Phil

[Paul Elliott]

Copper braid will corrode fairly rapidly in a marine environment. It's good when you need flexibility, but otherwise copper strap is more robust and just as good. Unless the braid wires are individually insulated (and they aren't), there is no extra effective surface area.

[ka4wja]

Phil,
First off thanks...but I'm not a professional RF engineer (I majored in physics), I just studied HF, etc. as an amateur...I've made my living in microwave, Satcom, wireless RF systems, etc...


As for "braid"...here my issues...
a) corrosion....which can be somewhat mitigated by using "tinned-copper" or SS...
But, even if using tinned or SS braid, you can still develop "semi-conductors"....all of those small wires moving around...not good in an RF environ...(causes RFI as well as possible intermittent RF conductivity)
If the braid is "encapsulated" (whether inside the jacket of a coaxial cable, or under epoxy, etc.), then much of this taken care of....but you'd still be better off with strapping..

b) thousands of small wires, making and breaking contact...again causing RFI, etc...

c) increased resistance / impedance, compared to strap...

I've seen braid used in DC circuits, no problem....but in RF environs, it can be problematic (not in all cases, but why take the chance?)
And, when you put it near sea water, well it then becomes very likely to be a problem, very quickly...

I've seen braid used in RF tank circuits by questionable engineers (it's cheap and easy to work with), and have seen it melted and/or burned...
Now, to be sure, it unlikely that you'd ever develop enough RF current in your ground system with a 150-watt radio to ever cause this to happen...but, still....braid just doesn't make sense (at least to me, or any RF engineers I know).

And, I will concede that if using tinned braid and it's encapsulated in epoxy, there is no real issue....but that's a lot of work to go thru...
If you want to do this, you should be fine...but, in my opinion you'd be happier just using copper strap...



Finally, as I wrote earlier....I think you're over-thinking this a bit...you don't have to re-invent the wheel...
Just install the system correctly, and use the best antenna ground / RF ground you can afford the time/money to install, and you'll be good-to-go!


Hope this helps.

John