Mobile Ops & Installing the “Sorta Base”
Now this is my primary mobile VHF setup:
And work continues on my primary “base station” (which is also sorta mobile) – the boat… below I’m constructing the high voltage cable that will connect my (end-fed) wire to the antenna tuner. After putting ring terminals on both ends,
I found that I needed a different terminal on the antenna end to fit around a half-inch bolt (instead of connecting to the bolt with a hose clamp as originally planned. So this is the tuner end of the feedline (soldered, crimped & shrink-wrapped):
and this is the antenna end:
Nice since there’s only two feet between the bottom end of the antenna (essentially a forty-five foot long wire, the top end of which is 50 feet up off the water, the lower end less than five feet off the water, a.k.a., salt water counterpoise) and the AH-4 coupler.
Now, I had to descend into some deep dark places on the boat to connect the antenna feedline and route the copper strap comprising my RF ground connection to the sea.
Here, I’m bidding good-bye to sunlight for awhile to make the feedline connections:
and again to route copper strap, the unbalanced (coax) feedline and tuner control line:
and this is where the RF ground strap will terminate – on the backside of two sintered bronze blocks on the OUTSIDE of the boat’s hull (bottom). What you see in the pic below are the plywood backing plates (and connecting bolts) INSIDE the hull, below the engine room floor boards.
Note the heavy green wire lower left that ties to the ship’s bonding system (DC ground). Obviously, that will have to come off as I intend keeping my RF ground separate from my DC ground (obviously?).
For approximately ten feet or so, the 3” wide 22 mil thick copper strap runs along the inside of the boat’s bottom a mere 1.5 inches (thickness of the hull) from the best practical counterpoise in the world–sea water.
That’s 30 square feet x two = 60 square feet (two sides) capacitatively coupled to the sea through the hull.
Plus the two bronze blocks (one boasts the equivalent surface area of 100 square feet, the second half again as much) will be directly connected between the strap and the sea via four bronze bolts and two gold-plated ones smothered in Ox-Gard and mechanically bolted lock tight.
That’s about as good an overkill on “the bottom half of my near-vertical (sloped) multi-band dipole” as I can contrive!
Tomorrow, I finished the copper strap install and start (and hopefully finish) on the feedline and control line to the radio.
The final step will be the power run from a new 30A breaker on order that will reside on an auxiliary breaker panel with eight gauged power cable.
Gettin’ close, radio fans!
73 dit dit
