Sorry, typo..."data knowns" not data knows...R
From: BVARC [mailto:[email protected]] On Behalf Of Rick Hiller via BVARC Sent: Tuesday, December 22, 2015 11:20 AM To: 'BRAZOS VALLEY AMATEUR RADIO CLUB' <[email protected]> Cc: [email protected]; 'Gary Sitton' <[email protected]> Subject: Re: [BVARC] Coiling ends of a dipole? A method to approximate the appropriate add-on length is to use a transmission line program, TL Details or ARRL's TLW.....IF you know the antenna feed Z and IF you know the feedline length in ft or w/l..then you can use the TL calculator to show you the TL's source end Z, as you add length a bit at a time. TL Details is dynamic-changes as you change the input fields and TLW is static, changes only when you push the enter key after changing the input fields. If you don't like computers, then use a Smith Chart, but you still need data knows to work it out. HI W5RH From: BVARC [mailto:[email protected]] On Behalf Of Gary Sitton via BVARC Sent: Tuesday, December 22, 2015 10:58 AM To: BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected] <mailto:[email protected]> > Cc: Gary Sitton <[email protected] <mailto:[email protected]> > Subject: Re: [BVARC] Coiling ends of a dipole? Michael: I have a similar 2nd floor shack situation (see QRZ page K5AMH). It's very possible to put a few feet or more of ladder line inside the shack and loop it to save space. An antenna analyzer should show you about how much feed line to add to solve the problem. What kind of antenna tuner or balun arrangement are you using? I have a highly modified Johnson KW MatchBox which is entirely floating from the ground (case) internally. This assures virtually perfect feed line current balance, i.e. no common mode currents. BTW, I have an interest in astronomy also and have a very nice vintage QSL collection here; every hear of Southern Rhodesia? 73, Gary K5AMH On 12/22/2015 00:06, Michael Rapp via BVARC wrote: Hi all, Thanks Josh, Rick, and Gary for the suggestions. It never occurred to me to try to adjust the length of my ladder line. I can't do too much here....my antenna mast is affixed to my house and my shack is on the second floor. The ladder line comes off the feedpoint and makes a nice arc into my second story window. If I have the feedline too long it will sit on a part of a roof overhang that goes over part of the first floor. Still, if I can just lengthen it enough to get a match on 40 meters, I'll be happy. Looks like experimenting time! -- /*/-=[Michael / KT5MR]-=/*/ _______________________________________________ BVARC mailing list [email protected] <mailto:[email protected]> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
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