[TowerTalk] "Great Spider" Antenna and G5RV Question

Mary-Frances R. Bartels ki0dz@juno.com
Mon, 25 Aug 1997 12:43:02 MST


Greetings Towertalkians,
   Over the weekend I built a very simple antenna for 6M.  I know that 6M
is officially VHF, but I the design could be reasonably adapted for 10M. 
Anyway after building a J-Pole that I couldn't get to load below a 2.8
SWR I decided to take the advice of someone else who suggested what he
called a 1/2-wave dipole with radials to help decouple the antenna from
the line.  I built it and put three radials on the braid (actually along
the last few inches of the wire that I then soldered to the braid).  I
ran the great spider (except for the fact that it only has four legs and
a long neck, it kind of looks like a huge spider, or, er, maybe a
Martian...) up my spruce tree which I am presently using for a tower.  It
is now at a height of 20+ feet and works better than the regular dipole
installed in my attic.  Sure, it has a narrow bandwidth, but that should
be no problem with the HF bands and is fine with my on 6 because my
primary interest is in the SSB portion.  Just a little piece of info to
pass on to others who may be building their own antennas.
   Now, my question...  I use a G5RV for my HF work.  It is strung from
the spruce in the front yard and ends in a tree in my backyard.  Since it
was one of my very first amateur radio antennas, I bought it
preassembled.  It came with the usual 70+ feet of thin coax attached to
about 30 feet of twinlead and possibly a balun from the antenna itself. 
I know that this sort of arrangement is fairly common.  My problem, if
you could call it that, is that I don't NEED the 70+ feet of thin coax. 
With the few antennas I have now (and it is only four) I already have a
mess of coax in the attic.  I'd like to use a smaller run of the thin
coax from the G5RV and probably use thicker, RG8-type stuff.  Has anyone
here any experience with deviating from the "standard" G5RV feed system
described above?  Is it reasonable to use less coax?
   Lastly, don't know if I've mentioned it here (think I may have) I'm
still in the market for an MFJ-259 antenna analyser.  Was wondering if
anyone wanted to part with theirs (I know, just about as much as Subaru
owners want to part with their cars) or knew of a retailer that charged
less than the $200+ price for it.
   Thanks for the bandwidth.
                                                        73,
                                                        Mary-Frances

Mary-Frances R. Bartels                         (((#)))     ^     ^
Amateur Radio Callsign: KI0DZ  DM79lt Denver, CO   |         ^ - ^
***Let ME scan your photos and documents!***    -------      (o o)
Ind. Rep. of Watkins products #92389            |ooOoo|    >{  |  }<
http://www.qsl.net/ki0dz                        -------           RRR)*

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