Jochen, As Michael says, we discussed this at length last year, and you may find some interesting posts in the paddlewise archives. I have experimented with various VHF setups and this may help you some: # My boat is a Klepper, so I have lots of room! and options for attaching stuff like antennae, fixed transceivers, batteries, etc! Not that I carry all this stuff on every trip! # I have used homemade antennae, with RG58 lead. # I stripped back 17 and three-quarter inches of the RG58, that is, cut back the outer covering and the metallic mesh surround. This gives you a length of transmit and receive inner wire which covers the VHF marine frequency bandwidth. I taped this to an ex army break apart whip antenna which conveniently folds down to roughly four sections of three foot lengths. [ Apologies for the 'imperial' measurement] Still figure in the 'old'way! # I made up my own antennae because I wanted something I could fold down and stow, but which would give me height if needed, but was light weight. # This set up lifts the business end of the antenna about 12ft off sealevel. Remember, it is the 'antenna line of sight' that is the vital ingredient in successful VHF communication. That is, the higher the antenna the better. [ Which gives yachts a distinct advantage with top of the mast antennae] # Remember also, this homebrew antenna has a short life. Seawater is anaethema to all your connexions. On the Klepper I can either use the standard mast step to rig the antenna, and I have also homemade a step behind my seat. # I have used this antenna set up with both my hand held and fixed 25w transceivers. The extra height certainly gives you an 'edge' , and I have made successful boat to shore communication over 25 miles which is about the limit for close to sea level VHF without the use of repeater stations. # The 'whip' in an antenna will certainly affect your VHF capability. Shakespeare, a reputable antenna manufacturer has actual recordings of how antennae are affected by sea states. [They may still have them on their web site] Your transmissions are affected by the angle of your antenna in relation to the receiving antenna. Vertical is best, which sometimes is not possible in a kayak! And the whip on a high antenna in a big sea is enough to degrade the signal. Transmit/receive may often be achieved equally well by the 'rubber ducky' antenna on a handheld, except at extreme range. So you have a trade off between weight, battery power/capacity antenna height, wave action, distance to your receiving station, if you know that, possible disruptions to transmission ie, headlands, islands etc. # I have no knowledge of European conditions in the VHF medium, but I guess it is crowded. In that case 25watt transmit power may be useful to 'dominate'. But it is the antenna, not the transmit power! You can achieve reliable communication on 1 watt most of the time! # I repeat, the efficiency and height of the antenna is the crucial factor in reliable VHF. # The brand of radio you mention is not known to me, but is presumably European. As someone has mentioned, standards of 'waterproofness' vary. Assume that nothing is 'waterproof' and you will be OK. # Bear in mind that on your full power , ie 25w, you are drawing five or six amps out of your battery on transmit. You really want a good reason to pump out that much electricity. And you may find that your radio transmit circuitry is designed to operate on the assumption that your battery is fully charged. This is important, below a certain state of charge, you may be able to receive, but not transmit. I use a solar panel to charge my battery on trips. This may not be a solution in an environment where there is significant cloud cover. # You mention paddling across busy sea lanes. This anti-collision device looks a practical aid which draws very little power. >http://www.survivalsafety.com/c_a_r_d.htm Good luck! Peter Rattenbury *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
I don't think I've seen anyone mention this so far so I will. If you're going to install a VHF radio in your kayak, it still might be a good idea to carry a handheld. A VHF radio in your kayak isn't going to help if you get separated from your boat. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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