Delta Loop Alternative to G5RV/Windom

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From: James R. Duffey (ji3m@scubed.scubed.com)
Date: Wed May 17 1995 - 14:08:27 EDT


I would suggest that you look at a delta loop fed with open wire feeders as
an alternative to either a G5RV or Windom. I have a 30M delta loop fed with
5M of open wirefeeder. This makes it 40 M from one end of the feedline to
the other, and my TS 850S internal antenna tuner loads it up well on 80,
40, 20, 15, and 10 with a 1:1 coiled coax balun connection. The 850s loads
it ok on 30, 17, and 12 with a 4:1 ferrite choke balun. An external tuner
should have no problem handling it on all bands.

If it is installed low, less than a half wavelength, tieing the feeder ends
together and feeding it as a vertical against a counterpoise (or ground)
results in a lower angle of radiation. This extends the range to 160 M as
well.

You could make an 80 M delta loop fit between the two trees, split the wire
length between the loop and the feedline to make access to it easy. Keep
the loop above 60 M or so and below 75M or so for the best results on both
80 and 40. Just as in a centerfed longwire, there is considerable breakup
of the radiaiton pattern at high frequencies and the main radiation lobes
may end up in directions that are not interesting. A smaller loop for the
higher bands may be more useful.

The delta loop has at least one advantage over the Windom/G5RV; higher
radiation resistance which results in higher efficiency and broader
bandwidth.

The G5RV feeders can also be tied together and used as a vertical on 40,
80, and 160.

Don't use long runs of coax with the G5RV as the losses will eat your power
on bands where the SWR is high. Bringing the ladder line to the tuner and
omitting the coax altogether will help this problem greatly. You can use
300 ohm twinlead to enter the house.

I did not create this wisdom, Moxon, G6XN, in his book "HF Antennas for All
Locations" advocates loops fed with open wire feeders as simple all band
alternatives to center fed Zepps, G5RVs, Windoms, and commercial trapped
verticals.

Good luck. Let us know what you decide.
Duffey KK6MC/5

James R. Duffey ((505) 764-3143)
Maxwell Laboratories, S-Cubed Division
2501 Yale Blvd SE Suite 300
Albuqueruqe, NM 87106-4125
ji3m@scubed.com


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