Interesting idea Thor.
If you like, you can line up REFLECTORS for each band
with 0.15 WL spacing to get directivity on each band
without interaction. Lower frequency Directors create
destructive interaction the higher frequencies which is
why 3L arrays require traps or multiple 'sleeve' elements
to isolate the lower frequency elements.
Tom N4KG
On Sun, 31 Mar 2002 "Thor Hallen" <thorh@worldnet.att.net> writes:
> Bill:
>
> I assume that your primary interest is DX from your post. Since
> towers or
> out of the question, it would seem that you are limited to
> verticals. You
> can improve the efficiency of a single vertical with a ground
> screen. You
> can improve the directivity and gain by going to a vertical array. I
> live in
> a restricted antenna neighborhood and have had good results using a
> screwdriver vertical mounted in the center of a 16 by 20 foot
> rectangular
> ground screen made from aluminum screen door material. The ground
> screen was
> covered with barkdust so as to not be visible. I have enhanced the
> performance on 15 meters by adding a parasitic director and
> reflector. The
> array was optimized using AO for maximum front to back ratio to
> minimize TVI
> that my neighbor was complaining about. With my neighbor to the
> rear, the
> array is pointed towards Europe and Africa. The measured F/B ratio
> on 15
> meters ( the only band that causes TVI )is appoximately 40 dB. The
> screwdriver and parasitic elements are short enough as to barely be
> noticeable above the fence top from the street. I get signal reports
> on 15
> meters comparable to others in the area with towers from Europe and
> Africa.
> I have gotten several skeptical responses when I describe the
> antenna that I
> am using. The antenna is also quite respectable on the other HF
> bands except
> 80 meters where the efficiency is less than 10%. The pattern is
> essentially
> omni directional except on 15 meters.
>
> Best Regards,
> Thor K5AGE
>
>
>
> -----Original Message-----
> From: towertalk-admin@contesting.com
> [mailto:towertalk-admin@contesting.com]On Behalf Of Bill Axelrod
> Sent: Sunday, March 31, 2002 6:37 PM
> To: Towertalk@contesting.com
> Subject: [Towertalk] Antenna choices in a restricted neighborhood
>
>
> I'm looking to tap the collective wisdom of this group. I live in
> an
> antenna restricted neighborhood. (Please no flames - there are real
> reasons
> why some of us live like this) While transmitting antennas are not
> allowed,
> I have been able to put up two - a Gap Titan and a G5RV as an
> inverted Vee
> with the apex at 36 ft. My back yard is rectangular, about 95 feet
> by 40
> feet. The vertical has been up for about 7 years so I figure I'm
> pretty
> safe from the Antenna Police.
>
> While I've done marginally well with this setup (~285 countries and
> DXCC on
> all bands 80 through 10), I know my set up is far from optimum. I
> want to
> do better. Short of putting up a tower and beam which surely would
> attract
> the Antenna Police, I'm looking for ideas on what I could do to get
> the best
> antennas I can in my available space and within the restrictions
> given.
> That limits me to two ~36 ft support poles and two PCV pipes at 10
> ft
> holding the ends of the Vee (similar in visibility to what I have
> now).
> I'd like to avoid (or minimize) the use of a tuner to aloow quick
> QSYs.
> Now, I use the Gap from 40 to 10 and keep the Vee tuned to 80
> meters. Cost
> is not the limiting factor.
>
> I would appreciate any ideas the group may have.
>
> Thanks and 73... Bill K3WA bill@axelrods.org
>
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