K0GKJ – Just Another Ham
The New QTH – A Floating Shack

HF Install on Boat Almost Finished

A radio shack aboard a liveaboard boat falls somewhere in between a shack at the house and a mobile rig in the car. Best of both worlds, I say!

I’m borrowing on my experience with mobile ops as well as gyrations in setting up a QTH at the house. Add to that those aspects of an HF rig on salt water and it makes for a fascinating exercise.

Mobile power rules of thumb:

  1. Use heavy gauge wire to minimize (12VDC) voltage drop. I’m using 8 gauge – even though my total run is about 25 feet (round trip). Marine practice dictates soldered connections which I then wrapped in Scotch Super 88 heavy electrical tape and covered all with marine grade shrink tubing: hf radio install 002
  2. Fuse positive and negative DC power cables as close to the battery(s) as possible…  hf radio install 003
  3. I also doubled up my protection on power with a 30A breaker which will go on this panel (notice the empty spot near the bottom: hf radio install 020

Snaking cables was one of the more challenging aspects of this installation.

Worst nightmare for any boat owner is drilling holes in his boat. Check out the two holes below (left hole drilled through 1.5” of the pilothouse bulkhead for the antenna feedline and tuner control line; the right hole through over two and a half inches of teak paneling and plywood bulkhead for power line from batteries !  hf radio install 008

Ultimately, I’ll have a neat electrical installation (I’ve been pretty fastidious on this phase of the install so it lasts a good long while as trouble-free as I can make it): hf radio install 018 

and the final result is actually sort of anticlimactic in appearance, but I’m hoping orgasmic in practice!

hf radio install 019a 

Since this baby will be just forward of my right shoulder as I’m sitting in my La-Z-Boy, I’ll need some sort of lap desk to operate from. Another design challenge!

I had to tear up much of the pilothouse to snake all the wires and get access to all those better-forgotten spaces:

hf radio install 011

hf radio install 012

INCLUDING uninstalling (temporarily) one of the bolted in safes on board):

 hf radio install 010

Unique to a marine installation is the technique for creating a strong RF ground, or counterpoise, via a combination of coupling to the salt water ground through the hull of the boat as well as direct (electrical) attachment TO the salt water via fixtures on the bottom of the hull that has bronze studs penetrating the hull. Here’s a view of the attachment from the antenna tuner located in the left rear corner of the boat to the bronze blocks in the bottom of the right side of the boat halfway forward – a place I seldom visit under the floorboards of the engine room…

Attachment via two bronze nuts, washers, lock washers and gobs of Ox-Gard to the smaller (twelve inch long) bronze block – the wood is the “backing plate” inside the hull to which the bronze block on the outside of the hull is securely bolted:

 copper etc 003

Forward of that twelve inch block is a larger eighteen inch long block. The RF ground copper strap is mated to its four bolts similarly…

copper etc 004

and here is a view of the two in tandem:

 copper etc 005

I then sprayed as much of the thirty feet of copper strap as I could with clear lacquer to protect it (at least partially) from tarnishing. In and of itself, that shouldn’t affect performance. It’s more just to increase its longevity. I figured any clear lacquer would do;

copper etc 008 

Notice the bronze floor latch in front of this cheapo Wal-Mart lacquer. The reason it still is untarnished after many months of walking on it? Yup.. sprayed it with the same stuff back then.

Now I have to climb the mast (54 feet high), take down one of the two backstay wires, saw about fifteen inches out of it to install an insulator, and that should just about get me on the air after I put that wire (antenna) back aloft and get my new breaker delivered. Oh yeah!

73   dit    dit


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