Re: [TowerTalk] G5RV

[Mahlon Haunschild <mahlonhaunschild@cox.net>]

Mike,

What you are experiencing with your G5RV antenna is as it should be. 
The G5RV is resonant antenna (but not 50 ohm impedance) on 20 meters, 
and presents reactive (but reasonable) loads to the transmitter on all 
other bands.  It is this way because the 102' length of the flat top is 
a 3/2-wave dipole on 20 meters; the 31' ladder-line section is supposed 
to act as an impedance transformer on that band to transform the 
feedpoint impedance to circa 75 ohms.

Louis Varney intended his antenna to be used with an antenna tuner from 
the get go (except on 20 meters, of course).

See Louis's article in the ARRL Antenna Compendium, vol. 1, pgs 86-90 
for further details.

regards,

Mahlon - K4OQ

KD8OK wrote:
> All, 
>
> I recently put up the G5RV that my wife purchased for me at Christmas.  After putting it up and taking it down 4 times, I must confess that I am at a loss.  
>
> Some background:
>
> My property is large enough for a G5RV, but not for an 80 meter inverted vee.  So I elected so ask "Santa wife" for the G5RV (one of the premanufactured ones available at the local ham radio store).  
>
> The antenna is supported by approximately 33' of mast at the center and slopes down to approximately 11 feet at the ends.  (High enough to keep the kids out of it.)  The ladder line is held away from the pole all the way down approximately 5 or 6 inches with a couple of wooden standoffs that I fabricated.  I also tried coiling about 7 or 8 - 6" turns of coax at the feed point per a suggestion I saw on a web site although this didn't seem to have any impact on the performance or SWR.  I also tried changing the length of coax feeding the antenna, but still not difference.
>
> My concern is this, while I get a good SWR on 20 (about 1.5 at 14.200), I am unable to make the antenna work on any other band without using a tuner.  The SWR on any other band is at least 4:1 or higher.  I had a G5RV about 20 years ago and seem to remember that it had a decent SWR on 80, 40 and 20.  I tried to play with the length of the wire, adding several lengths to the ends, but still could not find a resonate point on any other band.
>
> While I don't mind using a tuner, I am wondering if I am missing something.  I verified all of the dimensions (102' of wire and 31' of ladder line).
>
> Any idea?  I hope that I am not stirring up a hornets nest with this question.  
>
> Thanks in advance...
>
> KD8OK  -  Mike 

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