[Towertalk] GAO Challenger DX

[Steve Katz]

Interesting comments, Jim.

I don't have a 40m beam, myself, but we do at the contest station (K2XR) and
always maintain some vertical antennas to supplement the beam.

The 2L 40 at 90' works well; however, using a GAP Voyager (ground-mounted,
obviously) or wire slopers off the 140' tower at the site are great "go-to"
antennas that can easily outperform the 2L beam on occasion, depending on
propagation and path.  To use just the beam, always, would be silly.  I find
myself frequently switching to the Voyager or a sloper, to see which works
best for a given DX contact, and use that one to make the call.

Based on my various experiences in winter-months DX contesting from stations
having a mix of antennas, if I had to choose just ONE good 40m system to
stick with forever, I'd use a full-sized vertical like the Voyager for
transmitting, and a couple of Beverages, or a small rotary loop, for
receiving, most of the time.  Only problem with the vertical appears to be
that DX signals are all "S9+" and so is the noise....

WB2WIK/6

"If everything seems under control, you're just not going fast enough." -
Mario Andretti

> -----Original Message-----
> From:	Jim Shaw [SMTP:Jim@shawresources.com]
> Sent:	Monday, October 07, 2002 10:08 AM
> To:	TOWERTALK@contesting.com
> Subject:	RE: [Towertalk] GAO Challenger DX
> 
> 
> In general, I agree that the big variable at low heights (less than 1/2
> WL)
> is the ground. Always thought low HF horizontal dipoles are DX
> problematic,
> particularly on the low bands.
> 
> Its not clear to me if you are restricting your points to traditional 1/4
> WL
> verticals with radials, or if you intended the comments to apply to all
> verticals including 'vertical dipoles'.
> 
> I have been real interested in the FORCE12 move into 'vertical dipoles' of
> one flavor or another.
> 
> (See http://force12inc.com/sigmainfo-005.htm)
> 
> They managed to get a positive QST review (OCT 2002) on their 'stealth'
> Sigma 5 (9 ft or so high radiator on 20-10M). But they have several
> 'fuller
> size' models that they claim are 'DX-pedition proven'.  And, although it
> may
> be marketing hype (aimed at GAP?), they claim very high efficiency for
> their
> vertical dipoles even when mounted just above the ground!  Their use of
> 'capacity hats' to shorten their vertical dipoles seems quite practical to
> me as it avoids the issue of traps.
> 
> A consideration in favor of vertical vs horizontal dipoles for DX (e.g, on
> 80M where a 1/2 WL 80M dipole is 140 ft) is that dipoles must be rotatable
> to achieve omni directional coverage.  Or you may need two or three to
> cover
> all directions.  Even with efficient shortening, they can be
> geographically
> problematic as well as difficult to get high enough.  But, for those able
> to
> use 'brute force', these are not issues.
> 
> To me, each has pros and cons and circumstances will tend to result in
> choosing one over the other.  I try to know the strengths and weaknesses
> of
> each so I can use the best for the situation.
> 
> 73 de Jim WA6PX
> JGShaw@Alumni.HAAS.org
> 
> -----Original Message-----
> From: towertalk-admin@contesting.com
> [mailto:towertalk-admin@contesting.com]On Behalf Of n4kg@juno.com
> Sent: Monday, October 07, 2002 6:23 AM
> To: TOWERTALK@contesting.com
> Subject: Re: [Towertalk] GAO Challenger DX
> 
> 
> Ground Reflections from Horizontally Polarized antennas are
> very efficient, suffering only 1 to 2 dB loss regardless of how
> poor the conductivity of the ground.
> 
> Ground Reflections from Vertically Polarized antennas are
> HIGHLY dependent on the ground conductivity and are typically
> much higher than for horizontally polarized antennas unless the
> reflections are over Salt Water.
> 
> On the Low Bands, verticals are often better than (low) dipoles
> for DX where a 1/2 WL high 80M dipole needs to be 140 ft up!
> 
> Tom  N4KG
> 
> 
> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices, 
> See http://www.mscomputer.com 
> 
> Wireless Weather Stations now $349.95. Call Toll Free, 
> 888-333-9041 for additional information.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk