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How to use a simple SWR meter and what it means to your VHF
One thing to consider and weigh in is the actual difference to the
receiver you're talking to...on-the-air...where it matters. Look at any receiver or transceiver with a pseudo-calibrated S-meter. Notice the DB scale above S-9. See how the marks are 10 dB apart? This is also true down the scale. So, before you all go hauling 7/8" hardline up the mast and boring huge holes in the fiberglass to route it, the difference on-the-air, where it counts is that instead of your signal being S-9 on somebody's meter with 7/8" hardline and $200 connectors, you're RG-58 signal will only be S-8.5 and noone will notice any difference....(c; More CB myths. Most boats only have a 25-50' coax run. What I DO recommend is a good Belden foil shielded cable, which will require proper crimp connectors to make it work, not PL-259's from WalMart. The 100% foil shield will keep locally generated noise OUT of the cable on receive on its way from the antenna to your sensitive receiver. You won't have to listen to the cheap straight plugs marine engine manufacturers love to put in outboard and inboard motors, instead of the resistor plugs they should be using. The foil coax will also get a little more signal to the antenna on transmit, but "big deal"....(c; On Thu, 13 Nov 2003 09:33:27 -0500, Vito wrote: Marcus AAkesson wrote: On Wed, 12 Nov 2003 15:41:08 -0500, "Jim Woodward" jameslwoodward at attbi dot com wrote: 4) What do you like other than the cheap white crap for antenna cable? I used Belden 9913 (solid center conductor) on Swee****er. Is that still a good choice? RG214 or similar which is silver plated Cu in both conductor and shield. Raw copper will in time oxidize and deteriorate in the salty environment. I have seen some really ugly cables after only 5-6 years. Check out http://www.therfc.com/attenrat.htm Common RG-58A (the white crap) looses 7.4dB/100 ft at 200MHz. That's over half your signal used to heat the coax! RG-8X (mini-RG8 - the other white crap) is almost as bad at 5.4 dB/100'. Belden 9913 is excellent at only 1.8dB/100. RG-214 has 3.3dB loss/100' but as Marcus suggests may have better corrosion resistance. Of course if money, size and weight are unimportant there's LDF5 (c: Larry W4CSC "Very funny, Scotty! Now, BEAM ME MY CLOTHES! KIRK OUT!" |