[SCCC] K7JA's broadband, ladder-line fed dipole ANT at Visalia?

[Bill Haddon]

The K7JA antanna is a Zepp antenna, as described in Chapter 8 of the ARRL
Antenna Handbook, N6BV Ed.

i.e. a center fed wire using 450 or 600 ohm ladder line into a tuner with
an appropriate Balun.

If each leg of the Zepp is around 0.64 wavelength the broadside
(bidirectional gain) increases to about 5 dBi (3dB gain over a dipole).
Thus a 20m DE Zepp has an overall length, in feet, of 1.28 * (468/14.1) =
42.5 feet (probably not to critical).  That length, which is close to the
K7JA's 40 feet, will give excellent performance on 20m and very
satisfactory performance on 40 m.  It can be loaded on 80m with a good
tuner. The 3dB points (in DE Zepp configuration) are about 15 deg either
side of center  vs. about 45 deg for a standard dipole.  So if optimized to
the East Coast, it will may not be so good for Europe, but will be ok for
ZL/VK and N. Africa.

I'm currently using a 40m DE Zepp at about 75 feet.  For domestic contests
it's performance if outstanding on both 40 and 80 m and v. good on 30m.

If you're just using this type antenna as a 2nd antenna for contests, it
may be best to avoid the DE  Zepp length so broaden the coverage.

There could be increased noise pickup on the feedline. Better to use Bev.
receiving antennas if you have the real estate.

Using this type of antenna for20, 40 and 80m Q's I've had several Pacific
div wins in ARRL SS, low power.

73 Bill n6zfo
(NCCC)





On Fri, Jun 8, 2012 at 12:55 PM, H Lawrence Serra <hlserra at sbcglobal.net>wrote:

> Did anyone take notes on Chip K7JA's broadband, ladder-line fed dipole ANT
> talk at Visalia? I think it was about 40 ft each leg, fed by a certain
> length of ladder line fed to an ANT tuner. Chip suggested it as an
> emergency ANT or a supplemental contesting ANT for directions 90o to your
> beam heading.
>
> 73, Larry N6NC
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