[Elecraft] Antenna suggestions, resent
Ron D'Eau Claire
ron at cobi.biz
Sat Sep 28 19:15:38 EDT 2013
Dale's suggestion would also minimize the RF field directly under the
antenna and noise pickup from within the building. I'd probably go with a
trap vertical or a pair of verticals for 40 through 10 meter coverage since
a 1/4 wavelength on 40 is a full wavelength on 10 -- way too long for best
low-angle radiation.
73, Ron AC7AC
-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dale Putnam
Sent: Saturday, September 28, 2013 11:49 AM
To: elecraft at mailman.qth.net; k2vco.vic at gmail.com
Subject: Re: [Elecraft] Antenna suggestions, resent
Hi Vic, You have a perfect place, I love it. No.. not a lotta real estate..
but it is wonderful How about... a "a high as you can" vertical on the top
of your "shack" to be.. with 30 - 40 radials laid out and held in place with
sand bags, bricks, or the like.. maybe just tied to the edge... make them
long enough to reach the edge of the roof. If you can getthe vertical to be
43 or so ft high.. that's even better. Base feed with an auto tuner.
Second... a wire beam.. laid out at a convenient height on the big roof..
built to face East. or a J-K beam to face e-w. Look at the Great Circle map
to face to where you want to talk tothe most. Yes.. it would take a bit of
planning ahead... but you could even rotate it.. say for the all asian
contest... or for the TX QP.. move it a day ahead of the event.For the
domestic contests... face towards the middle of the country. No problem.
The vertical will do dx very nicely from there... and the wire beam would do
domestic nice too.Good L uck, Oh.. and for vhf.. a J-pole does great from
that high.
Have a great day,
--... ...--
Dale - WC7S in Wy
> Date: Sat, 28 Sep 2013 11:37:32 -0700
> From: k2vco.vic at gmail.com
> To: kl7uw at acsalaska.net; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Antenna suggestions, resent
>
> Here is a diagram of my space (use fixed width font):
>
> ----------------------------
> | | | |
> | | | |
> | | | |
> | ----------------- |
> | |
> | |
> ----------------------------
>
> The small rectangle on top is a small building (10'x20') on top of the
> roof of the 10-story apartment building. Actually, it will be my
> bedroom (and, I think, shack). The larger rectangle is the roof area
> at my disposal. It is about 10' x 30' plus the areas at the side of
> the building. The rest of my apartment is below the roof.
>
> I would love to put a little roof tower on the building with a beam on
> it! But as far as I know, that is not allowed.
>
> I am thinking about verticals, about 3 fiberglass masts holding up a
> shortened 40m dipole, etc.
>
> For 6 and 2 m I have 3 element beams which are small enough that they
> will be allowed.
>
> On 9/28/13 8:01 AM, Edward R Cole wrote:
> > Vic,
> >
> > Too bad you cannot consider a yagi for 20-10m. That would sit on a
> > mast secured to the small roof-top building. So a 30x 10 foot
> > space? I wonder if the 20x10 foot building extends beyond the 30x20
area?
> >
> > It it extends so total length is 50-feet You could put up a doublet
> > across the length, either horizontal with 8 foot droop on both ends
> > for full length half-wave on 40m or perhaps a pole in the center for
> > inverted-V. Another idea is 50-foot with 8-foot legs at
> > right angles but horizontal at the same height. Or consider a
> > 120-foot horizontal loop if there are places for four support poles.
> > Being on roof of ten stories means the wire does not need to be very
high.
> >
> > An automatic tuner at the roof would finish off any multiband
> > antenna with single coax run to shack. To add 6m/2m simple solution
> > is a base-loaded 5/8 6m wave vertical (could be a mobile whip).
> > They load fine on 2m as well (trick of VHF mobile stations).
> >
> > 73, Ed - KL7UW
> > ----------------------
> > Date: Fri, 27 Sep 2013 21:47:41 -0700
> > From: "Vic, K2VCO" <k2vco.vic at gmail.com>
> > To: elecraft Reflector <elecraft at mailman.qth.net>
> > Subject: [Elecraft] Antenna suggestions, resent
> > Message-ID: <52465F6D.9060505 at gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > I just realized that my previous message was sent in html format.
> > Which means that the reflector stripped the text! That explains some
> > of the answers...
> >
> > Here is what I meant to ask:
> > --------------------------------------------------------------------
> > --
> >
> > I am moving to an apartment on the top floor of a 10 story building.
> > I have access to the roof which has a 30' x 10' flat space. On one
> > edge of this space is a building 9' high with a flat roof of about
> > 10' x 20'. I can put up antennas on top of this little building and
> > on the flat area mentioned above.
> >
> > But there is a catch: the antenna has to be either a wire antenna,
> > or substantially vertical. If vertical, it can't exceed 29' in
> > height above the roof of the small building. Beams not allowed!
> >
> > I want to operate on 40 through 15 meters. The antenna needs to be
> > able to handle 1500w.
> >
> > I prefer horizontal antennas because of the extra gain and lower
> > noise pickup. I prefer a balanced antenna because of noise and RFI
> > considerations. But I'll consider other options if there are
> > overriding advantages.
> >
> > Suggestions
> >
> >
> > 73, Ed - KL7UW
> > http://www.kl7uw.com
> > dubususa at gmail.com
> > "Kits made by KL7UW"
> > ______________________________________________________________
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> >
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>
> --
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
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