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#1
posted to rec.boats.electronics
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Antenna wire for SSB
I'm planning on installint a 23' whip antenna on my boat with a antenna
tuner. I wondering what wire (size, type and grade) I should use from the tuner to the antenna (not coax cable)? |
#2
posted to rec.boats.electronics
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Antenna wire for SSB
"Wet-n-Wild Bill" wrote in
m: I'm planning on installint a 23' whip antenna on my boat with a antenna tuner. I wondering what wire (size, type and grade) I should use from the tuner to the antenna (not coax cable)? #12-14 is fine, but the most important thing is it should be something that won't corrode like stainless strap with holes drilled for the tuner's output terminal. Copper is just eaten..... The other most important thing lots of installations forget is this strap is part of the ANTENNA and is NOT a transmission line. It should be as short as possible and MUST NOT BE AGAINST OR NEAR ANYTHING CONDUCTIVE, or it will make that object part of the antenna solution. I see this wire neatly tywrapped to metal rigging to make it pretty all the time. Of course, then the RF couples through the insulation on the wire and gets sucked off into the rigging, or a metal box or some neat fitting they put it through, sucking up the RF energy instead of radiating it. The energy, unlike AC power, flows AROUND the conductor, not through it, exactly. It radiates from it, as part of the antenna. So, if you get it near any wiring, say some cables for other electronics because you're trying to hide it from view, all those cables will be RF "hot", REALLY hot at some frequencies where the impedance at the bottom of the whip is quite high, and can destroy the equipment the cables are hooked to or at least screw up their electronic operation. One guy said every time he talked on HF/SSB, his radar reset and the screen went crazy on his digital display. Further investigation found the tuner hidden away under the flybridge console to keep it pretty with the tuner to antenna link wire neatly tywrapped to a cable bundle going that way. The whole cable bundle was RF "hot" when the transmitter was on. On receive, of course, he heard every data bit that switched in the cable...on his HF receiver. Keep this wire far away from anything and screw the "pretty" if you want to get a good signal on HF/SSB. The tuners are waterproof, mount it right under the whip and feed the coax and control cables through the bulkhead. And NO TYWRAPPING TO THE HANDRAIL, EITHER! |
#3
posted to rec.boats.electronics
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Antenna wire for SSB
"Wet-n-Wild Bill" wrote in message m... I'm planning on installint a 23' whip antenna on my boat with a antenna tuner. I wondering what wire (size, type and grade) I should use from the tuner to the antenna (not coax cable)? As usual, Larry's tips are worth listening to, but the standard wire used in these parts is GTO-15. It's high voltage insulation provides considerable mechanical "stiffness" so it is nearly self-supporting over short distances. Terminals are usually uninsulated crimp-on "ring" type that are slightly "wick-in" soldered from the "ring" end only. (after crimping with the proper tool, of course) Then two or three layers of UV resistant heat shrink tubing over the wire to terminal joint for a little mechanical support and water proofing. There are crimp-on "ring" terminals that have metal two or three times as thick as the usuall hardware variety, but darned if I can remember just who makes them. These thicker ones will last a long time. A couple of coats of painted on "liquid tape" on the completed connection will help keep the joint dry and corrosion free (ya suure)! Done carefully, the GTO-15 wire lead will last longer than the 23' fiberglass antenna. Good Luck Old Chief Lynn |
#4
posted to rec.boats.electronics
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Antenna wire for SSB
Thank for info!
I forgot to mention that the boat is all metal (aluminum). You stated that the strap should be short! my intent is to place the tuner three to four feet from the antenna and mount it exposed to the elements on the roof. Any problems other than Dacron Guywires need when mounting on an aluminum roof? Also on near by will be other RF cables for Weather Fax and VHF, where as my GPS and Radar are 14' away! Bill |
#5
posted to rec.boats.electronics
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Antenna wire for SSB
Forgot to ask!
The antenna coupler ground wi Since the boat is all aluminum can i use the cabin's aluminum mounts or must i run a foil to my central ground point? Bill |
#6
posted to rec.boats.electronics
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Antenna wire for SSB
"Wet-n-Wild Bill" wrote in
: I forgot to mention that the boat is all metal (aluminum). You stated that the strap should be short! my intent is to place the tuner three to four feet from the antenna and mount it exposed to the elements on the roof. That would require the use of standoff insulators to hold the strap, even insulated wire steadily away from the metal hull. If the wire is flopping around, moving back and forth near the metal hull, it will constantly detune then tune then detune the antenna, especially on some frequencies where the impedance at the bottom of the whip is high. The tuning solution needs to be fairly stable, so the wire needs to be stable. Any problems other than Dacron Guywires need when mounting on an aluminum roof? Also on near by will be other RF cables for Weather Fax and VHF, where as my GPS and Radar are 14' away! Don't let the wire from the tuner to the antenna anywhere near any other antennas. If it must be near other coaxial cables, these cables need their shields bonded to the hull as soon as they go inside the boat to prevent the outside of the coaxial shield from becoming an HF antenna, leading the transmitter's RF right into the connector on the equipment. Bonding is simple, out of the weather. Skin off a small ring of the coax's outer plastic shield, wrap some wire around the outside of the coax's braided shield, then ground that to the nearest screw into the metal hull. This will drain off the RF at that point to hull ("ground") so it doesn't follow the outside of the shield to the equipment the coax belongs to. Best would be small plate welded to the hull with coaxial connectors running through it, those double female through-the-chassis connectors with females on either end. The coax then uses standard coax connectors to connect the cut cables to the plate's ground plane. Mine is a 4X8" stainless plate with two U clamps to an 8' ground rod outside my ham station. The RF following the cables down from the antenna, bleeds off to the ground rod on one side. The RF going through the connectors, of course, is INSIDE the cable and is unaffected. The outside of the coax going into my house is RF free, now out of the antenna's big field. This is a bigger issue when you're running 1500 watts PEP SSB...(c; POWER is our FRIEND. |
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