Here goes... this is a primer, there's a lot to learn here. My best advice is to hire a professional for this installation
. It really pays off in performance. DISCLAIMER: I do this for a living; I don't want to do yours <grin>
Ketches present some specific difficulties as well as a few unique opportunities.
Let's deal with the issues that AREN'T unique to ketch
(and, for that matter, yawl and schooner rigs).
A good installation has:
--good, tight connections everywhere
--a proven ground/counterpoise system (trial and error here)
that tunes easily and radiates well.
Only the last, the antenna, is unique to multi-masted vessels.
As posted here by Bill Trayfors (WA6CCA, search for his posts) and others, a good, solid power supply is critical. Wires of at least 6awg should run directly to the battery
system. Crimps should be very strong and heat shrunk. If you experience a voltage drop at the rig consider a voltage booster such as the outstanding units from TGE
(The N8XJK Super Booster
They are easy to install and will guarantee your radio 13.8 volts even when house batteries
are down to 10 or so. They really work
Antenna connections should be professionally soldered and heat shrunk as well. For boat
installations we recommend either RG-213 or LMR-400 Flex. These are much sturdier and have less loss than the more common RG8X. Where they pass through hull
areas Blue Sea Cable Clams work
Don't underestimate how much the boat may move; Kenwood sells good mounts for both the rig and remote head
; bolt them in with good washers and secure all wires every 18"
You don't mention the tuner you intend to use. I strongly recommend the SG-230
but this advice works for any similar unit.
Counterpoise/RF ground issues are a bit more complex. Search for posts here and you'll have a year of reading material. I've found that every installation is different. As a rule
I prefer multiple "radials" cut to 1/4 of the expected operating frequencies. For example, if I'm going to be working on the maritime net (MMSN/14.300 USB), a 20 meter band, I'd have a couple of 20 meter radials, 1/4 of 20 is 5 meters or about 16 feet. Double that for 40 meters, etc. In my case they are strung around insulators on the top of the engine
is a fairly successful attempt to simplify that. It works, while other things may work better. I also like to tie the ground system into above waterline metal such as toe rails and life lines where practical. Connecting to thru hulls and/or "dynaplates
" helps also and may reduce the receiver noise
. You'll note this is full of "mays" and "mights." While the science is pretty well developed in this area practical installations are largely trial and error to see what works best.
Now for that is unique to ketches...
Multi-mast rigs have issues with detuning that others don't. They have far too many wires in far too many places for a traditional split backstay to work well. What I settled on after three years of testing:
Insulated the STB MIZZEN SPREADER TIP, MIZZEN STB CAP SHROUD
, and the TRIATIC STAY, jumped between them with SS wire secured with u-bolt clamps. Bottom fed the "inverted L" antenna via a 4x1 UnUn transformer available from Balun DesignBalun Designs LLC - High quality baluns and ununs at reasonable prices
. You could skip the transformer but it really helped keep the radiation on the antenna and not in the "shack;" LINE ISOLATORS such as the T4 from RadioWorks The RADIO WORKS
help a great deal also.
We've had great success with this set up. I notice that your rig picture doesn't show a triatic stay but I'd say an "antenna stay" between the main mast
and mizzen jumped to a mizzen cap is the best antenna for a ketch. It keeps most of the radiated energy outside the other rigging
Again, this is really a job for a professional in my opinion.
Contact me directly for more info,