Join Date: Aug 2006
Location: Arlington, VA
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Re: Still holding its own - HF Radio
Excellent article by Jeff, and a good summary of the value of SSB and of installation basics.
I install SSB's professionally, and I have just two things to add.
1. Fusing/circuit breakers. Jeff's right that good clean power to the radio is essential, and the example he gives is right on: AWG6 marine cable for runs up to 20' round trip, AWG4 for longer runs. However, you need a fuse or circuit breaker in BOTH the positive and the negative wires, located close to the house batteries. And, most circuit breakers will not meet ABYC specs insofar as ampere interrupt capacity (AIC) is concerned. AIC must be in excess of 5,000 amps, and only the new high-AIC Blue Sea Systems breakers will meet this standard. Much easier to use fuses. Two common types are OK for this purpose: ANLs and MRBFs. The smallest ANL you can find is 40A. MRBF's come in 30A sizes and up.
2. RF Grounding. This is a little understood part of SSB installations. The implication in Jeff's article is that wire can't be used because RF travels on the outside of conductors, so only use wide copper, etc. This is WRONG, despite how often you see it repeated in manufacturer's instruction manuals and in texts on SSB. If that were true, how would a wire dipole work? And how come it's the STANDARD against which all antennas are measured?
The use of aluminum toerails, lifelines/pushpit/pulpit structures, metal rubrails (like on Island Packets), and other solutions can work fine, but sometimes are a lot of work to implement. Radials, both tuned and untuned, work very well. There's no need to physically couple to the seawater. In fact, the evidence is that elevated radials work better than buried radials. One of the simplest effective solutions is to use the KISS-SSB Radial Counterpoise System....very easy to install, and it works as advertised.
Again, thanks to Jeff for his excellent summary of the use and value of SSB to the cruising community.