That's true. Indeed, if you have an "antenna tuner" (built-in automatic or external manual) you don't even need to do that. That's what made them so popular in recent years; they "fix" impedance problems at the rig end without fiddling around with the antenna at all.
The issue then becomes feed line loss. It can get quite high, especially at the higher frequencies and with longer lengths of coax. It's not unusual to throw away 50%, 75% or more of your RF as heat along a coaxial line that way. But, if your antenna is designed to provide a decent match, or if you've done some adjustments 'on the ground' that suggest you're at least approximately correct, you're not likely to experience such drastic losses even though things will change when the antenna is raised to its final position. Doing measurements up on a tower is one of the major reasons for the popularity of the modern "antenna analyzers". They're self contained and small enough you can carry one up to the feed point. Most Hams only need to do that at rare intervals, which is why many Ham clubs have a "club analyzer" everyone's contributed to buying so members can borrow it on occasion. A much cheaper approach is, as Bill says, to cut some coax to a multiple of 1/2 wave, electrically. Then the impedance you see at the end on the ground will be the impedance at the antenna. The issue there is "how many times do you want to climb the tower"? Perhaps a buddy at the rig on the ground and you in the air with some HT's is the answer to that. Ron AC7AC -----Original Message----- Since I don't plan on hanging off the side of the tower to operate my station, isn't it more prudent to tune the entire "system", flaws, feedline and all if my main concern is what SWR my equipment, in my shack, sees? Charlie KI5XP _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
