Peter -- on this side of the pond, it's common to use a completely-isolated backstay for the antenna. I'd be concerned about getting RF burns if you don't isolate at the top (using the mast and the rest of the stays/shrouds as antennas); and depending on your transmit power, you'd need quite a large relay to switch the mast/rigging in or out of the circuit anyway.
Are you using an antenna tuner between the radio and the antenna? Most SSB installations I'm familiar with use an auto-tuner along with the fully-isolated backstay. See if this helps: http://www.yachtcom.info/backstay/index.html Fred Street -- Minneapolis S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( On Jan 11, 2013, at 4:08 PM, Colomba <colo...@peter-gottwald.de> wrote: > Good day > > last October I made my ham radio licence. Whatever, hard stuff. > Of cause my main idea is to bring the ham radio onto Colomba (C&C34) and I`m > wondering ho to install the antenna. Perhaps someone had same idea and some > solutions. > > In the moment I`m modelling the boat incl. rigging with 4nec2 and the results > are interesting ... and a little bit confusing. Up to now I made two setups > of antennas, one separate on the stern with max 8m long wire in a glasfibre > tube, app. 10° showing aft from the vertical. I`m not very pleased to have > such antenna, much to complicated for mooring etc. Also it seems that this > antenna will not work without a huge ammount of losses even if matched by an > antenna tuner. > The other possibility is to use the aft stay. It`s isolated, so in general no > problem. But, it`s funny ... isolated no chance to match it on 40m band, 80m > is possible but not really good. 20,15 and 10m are working. Than I`ve tried > to use the aft stay without an isolation in the top. Result was interesting. > 80m working good, 40m perfect, 20 and 15m do not work, 10m excellent. That > the 10m is working coupled to the whole rigg is realy surprising me. My idea > is now to place a relais in the top to have a circurit with the rigg or to > isolate the aft stay. Of cause, under all circumstances I have to match the > antenna with an automatic tuner, but I want to reduce losses in the tuner as > much as possible. > > Perhaps someone has his/her own experience and can give me some advices. If > someone is interesting in the nec file, please give me a note.
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