View Single Post
  #3   Report Post  
posted to rec.boats.electronics
Lynn Coffelt
 
Posts: n/a
Default use aluminum toe rails as SSB ground?

Recently read a suggestion saying you could use aluminum toe rails and
your
lifelines as part of your SSB radio grounding system. Just run foil from
the antenna tuner ground to the toe rail bolts?
Seems easy to do so I'm wondering if it really would improve your

grounding
system.

I've had good results using a toe rail counterpoise for HF SSB systems.
It is particularly useful of sailboats on which the metal loaded keel attach
bolts are either not used or non-existent. (the big lead or iron keel slug
being probably the best RF ground) There are a couple of thoughts here that
might be helpful:

1. The toe rail is usually more than one piece on each side of the vessel,
so those pieces, where they join, end to end, should be linked with a short
copper strap at each end's attach bolt (below decks, of course).

2. The attach bolts sometimes have enough 5200 sealant around them that they
make poor electrical contact with the toe rail itself. Be sure that there is
actually good electrical contact there (ohmmeter comes to mind).

3. Since each side of the toe rail becomes a leg of the counterpoise, and
the shear length of the rail comes closer to what the HF SSB tuner is
looking for, feed it to the tuner's ground stud from the extreme end of the
toe rail...... short copper strap is best, one strap to each side of the
vessel. Oftentimes the tuner in the lazerette or under a cockpit seat is
convenient. (especially if a fairly short antenna lead to the back-stay is
contemplated).

4. If the tuner is located in the lazerette (or fairly close), don't forget
the rudder post has excellent ground possibilities. It's either direct
contact or capacitance through paint or fiberglass to sea water are perfect!
A stainless steel hose clamp and some flexible, braided copper cable work
pretty well here. Keep it simple here, as it will seldom be free of moisture
(or sloshing sea water) the connection here will deteriorate over time, and
should be cleaned up before any offshore adventures.

All vessel RF ground system connections should be considered
"temporary" unless they are soldered or welded. They deteriorate with time,
even if the vessel is stored all winter on land. Take 'em apart, scrape and
clean and tighten 'em regularly before squirting and smearing some silicone
sealant (or grease...........your choice) around them.

Old Chief Lynn