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#11
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"Roger Halstead" wrote in message The tuning is quite different when I move away from resonance. One runs through trees and the other is over an open yard. Roger, Does the one that goes through trees change in SWR from day to day? Tam/WB2TT |
#12
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On Sat, 4 Oct 2003 16:23:16 -0400, "Tarmo Tammaru"
wrote: "Roger Halstead" wrote in message The tuning is quite different when I move away from resonance. One runs through trees and the other is over an open yard. Roger, Does the one that goes through trees change in SWR from day to day? It doesn't appear to, but as I always have the tuner in line and do a lot of band switching, I'd probably never notice. I can say that when switching from one of the other bands the tuner settings can be set very close by a chart. Nor do I remember having to retune with changes in the weather. One other thing to remember is that those trees are *wet* whether it's raining or not as far as the antenna is concerned. Roger Halstead (K8RI EN73 & ARRL Life Member) www.rogerhalstead.com N833R World's oldest Debonair? (S# CD-2) Tam/WB2TT |
#13
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The effect of a tree is hard to predict. If it's wet, and if it contacts
your antenna at a high impedance point, then the tree will become part of the antenna. It's going to be a pretty lossy conductor, so chances are that it will rob the antenna of some signal by dissipating it. But I can see situations, though unlikely, where it could conceivably improve things. Few of us can put up the ideal antenna, so they're all compromises of one kind or another. We just do the best we can under the circumstances. You have to weigh the nuisance of center feeding or other modifications against the possible benefits, and make your choices. But if you want to improve your reception, something is going to have to change. Roy Lewallen, W7EL Nick C wrote: Roy, Yes, thanks. That confirms most of what I already knew. About that tree question though... that one threw me. I thought for sure, if the tree was wet (which will be about 99% of the time from now on)... would 'remove' the energy from any signal hitting the wire..? The reception quality with aspect to it's wavelength makes sense, and I understand that. And yes, I have thought about using a dipole, but you clarified one point -- that it's not multiband. Although there are a few vendors who sell these SWL type antennas. Most are end-fed, but there are a few that are center-fed. Center feeding would be a lot harder for me to set up -- a lot more coax cable to run to my rig! PS. My coax is actually pretty horizontal. I have to fling it over some other objects, so it actually stays about 90% horizontal. My computers/tv/video don't seem to affect it too much with coax. My old set up -- with just plain incoming wire... was really bad with QRM -- as expected. Thanks -Nick n7zya |
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