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#51
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Yacht Rf ground and radials
For use in salt water, a number of Cu alloys have "excellent" corrosion
resistance. Among those that are available are the Admiralty Brasses (C44300 with As or C44500 with P). They have about 25% conductivity wrt to soft Cu. (Brass is mostly Cu and Zn.) Phosphor Bronze (C52100) is also a candidate with 13% conductivity. This is particularly good for antenna wire use. Pure Cu is expressed as having "good" resistance. Find a thin plate of Admiralty brass and bond Cu or phosphor bronze wire to the plate. Put the assembly into the water as "ground" and you are done. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: |
#52
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Yacht Rf ground and radials
Reg Edwards wrote:
You are all making a song and dance about it. And it seems I don't know the words. Whatever the ground electrode system happens to be, the impedance to Earth cannot possibly be less than the series impedance of the connecting lead. Which can be quite high at HF. Yes, but who's to say where the connecting lead begins. Simply imagine the antenna extending all the way to the ground electrode system and the tuner inserted, say four feet above it. The tuner may need some RF choking, of course, but ground lead impedance is now near zero ohms. In my opinion, the most effective ground will always be a short, thick, direct connection from the radio equipment to the internal hull of a metal boat. Not so practical a solution from inside an FRG hull. If you like, you can connect whatever else you have in mind in parallel with it, probably at the other end of a long lead, and it won't make the slightest improvement in performance. Certainly true for a metal hull in sal****er. Just use your loafs. And Happy sailing! ---- Reg, G4FGQ. 73, Chuck ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#53
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Yacht Rf ground and radials
In article ,
"Reg Edwards" wrote: You are all making a song and dance about it. Whatever the ground electrode system happens to be, the impedance to Earth cannot possibly be less than the series impedance of the connecting lead. Which can be quite high at HF. In my opinion, the most effective ground will always be a short, thick, direct connection from the radio equipment to the internal hull of a metal boat. If you like, you can connect whatever else you have in mind in parallel with it, probably at the other end of a long lead, and it won't make the slightest improvement in performance. Just use your loafs. And Happy sailing! ---- Reg, G4FGQ. True, except most of the folks discussing Rf Grounds here aren't working with metal hulled vessels. They are dealing with wood or plastic (Fiberglass) hulls, where an effective RF Ground is significantly harder to build. |
#54
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Yacht Rf ground and radials
Reg Edwards wrote:
A 6" square plate makes an adequate ground when immersed in salt sea water. That is unless the transmitter power exceeds 10 kW. I wonder.... It has been awhile since I checked, but does AES or HRO still sell those 8 ft "water rods" ? ?.....George |
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