Marine radio question for KAZ

[Rather Be Lucky]

Kaz, I read a previous post of yours pertaining to the length one can cut the antenna wire for the marine radio. I have mounted a Shakespeare Galaxy 4' Little Gaint (5401-XT) in my boat. I have routed the wire away from any thing that could cause any interference, and now want to cut the wire to the right length and solder the end. In your post you had given a minimum dimension and a multiple at which to cut the wire. I can't remember the numbers. I also think you were refering to an 8' antenna, but don't know if that matters. Could you please tell me those numbers again with my antenna in mind? Where do you measure from? The base of the antenna, where the wire comes out, tip of the antenna??? Any and all info will be greatly apreciated. Will probably have to pull the wire back, measure and mark it in the correct increments, and start over, but want it right. Thanks in advance, Swede

[Kaz]

Swede: I generally use the cutting measurements from the base of the antenna. But if the coax runs up into the antenna through an mount, then that should be the starting point. The numbers are; 3,5,7,9,etc times 17.9 inches (1/4 wave length of the frequency on Marine band), so the length of coax would measure 53.7", 89.5", or 125.3". Pick the length that works best for you, don't coil it just stuff it out of the way. I'm not sure if the length of the rod should be adjusted without checking it with a SWR meter or an antenna analyzer. Be careful when soldering the PL 259 connector on. The shield likes to short to the center conductor. I cut a piece of electrical tape in a small circle and punch a hole in the center to push the center conducter through before inserting it into the 259. This helps to keep the shield from shorting when you crank the reducer for the coax into the connector. Check for a distant weather station and if it come in fairly good, then it's OK to try to transmit to somebody else. If you hear nothing, loosen the the connector and keep just the center in the radio, and see if you hear any local WX. If you do, then the connector's got a short. Undo it and start over. Really the best is to find someone with a meter to check the output and the reflected power. If you can find a Ham Operator in your area, they'll have the test equipment to check it out. Most of the guys will do it for the fun of it. If your around the Twin Cities, I'll be glad to help....Kaz

[Rather Be Lucky]

Kaz, Thanks for the quick reply. The antenna came with 20 of cable with the end preped for the connector. That is how it was advertised in Cabela's (20'), I didn't measure it. So rather than pull it back, I'm going to do the math, subtract it from the 240", and go from there. Just wondering why they send an amount of wire that doesnt match the numbers your multiplier equals. 232.7" is slightly shorter than 20'. Should I just consider the cable to be 232.7" with the way it is intrnally connected, and do the math from there? Looks like I can only cut off 35.8", and I can even find room for that (without coiling), so will take a closer look and might not cut it at all. Thanks again for your help. You helped me a couple of years ago with a filter issue, so I knew who to ask. Swede

[Kaz]

Swede: 20' take or give a little, is 13 times the 17.9 inches. it may be only 19.39 feet, which is in the realm of saying 20'. If it's a little longer, then it will match at a little lower frequency, no problem. Solder the PL259 on without cutting and see how it works. you can always cut it later, putting it back is a big problem, LOL. Most of the time people don't need that much coax and cut it alot shorted...Kaz