[ARC5] Antenna for small yard

Fri Oct 21 23:33:56 EDT 2016

Wouldn't those impedances assume a really good ground radial system?

On 10/21/2016 11:25 PM, J Mcvey via ARC5 wrote:
> Ok, just for fun I modeled a vertical close to ground .
>
> The results for 80 centered on 3.75 MHZ for 33 feet ( 10.065M) was 6.57-j357 
> which is in the tuning range
>
> I modeled my 23 foot (7.015M)  wire vertical on 40 meters centered on 7.15 
> MHZ  and I  got 12.9-j265
> and for the 18 foot (5.49M) wire it was  6.57-j397
> which is also in the tuning range as I have actually verified.
>
> Models aren't the end-all , but I thought the results were compelling...
>
> -Jim M
>
>
> On Friday, October 21, 2016 10:45 PM, George Babits <gbabits at custertel.net> wrote:
>
>
> I've been watching this thread and finally decided to comment.  We are
> talking ARC-5 here and they were all designed to work into a pretty raunchy
> antenna - - - mid-fuselge to vertical stabalizer of an aircraft.  That could
> be anything from a B-25 or C-47 to a B-29.  Something in the order of 25 to
> 45 feet.  The roller inductor in the ARC-5 transmitter is the matching
> network and/or loading coil.  If the ARC-5 transmitter is original it should
> work into just about any length antenna.  Antenna theory and or "modeling"
> just doesn't fit in this case.  String up what you can, adjust the roller
> coil for maximum current (or field strength) and have fun.  Why make it all
> so complicated?
>
> By the way;  when I was in highschool and couldn't have an antenna,  I
> loaded the gutter/down spout system and did just fine on 80 and 40 meters.
>
> The more we learn and the more gadgets we have to measure things,  the more
> difficult it becomes to be satisfied with the simple way of getting a signal
> out.
>
> 73,
> George
> W7HDL
>
>
> ----- Original Message -----
> From: "Jim Wiley" <jwiley at gci.net <mailto:jwiley at gci.net>>
> To: "J Mcvey" <ac2eu at yahoo.com <mailto:ac2eu at yahoo.com>>; "Glen Zook" 
> <gzook at yahoo.com <mailto:gzook at yahoo.com>>; "AKLDGUY ."
> <neilb0627 at gmail.com <mailto:neilb0627 at gmail.com>>; "Mike Everette" 
> <radiocompass at yahoo.com <mailto:radiocompass at yahoo.com>>; "ARC-5
> List" <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>>
> Sent: Friday, October 21, 2016 8:10 PM
> Subject: Re: [ARC5] Antenna for small yard
>
>
> > Keep in mind there is nothing anywhere that says an antenna must be
> > "naturally resonant" or any specific length whatever to be a good
> > radiator, nor  is it necessary for an antenna to have a low SWR at 50
> > ohms to radiate well.  There IS a requirement that the antenna (and
> > feedline)  be adjusted in such a way that a "conjugate match" exists
> > between the transmitter and antenna. The antenna should probably be at
> > least 1/4 wavelength at the lowest frequency being used,  but don't be
> > afraid to try shorter, longer or even random length wires.
> >
> > If the feedline is of low loss construction (think open wire feeders),
> > and the antenna coupling unit (antenna tuner) is properly adjusted, any
> > reflected power will simply bounce up and down the feedline until it is
> > eventually radiated.
> >
> > Antenna theory is complex at best.  Consider the next two points:
> >
> > (1) One of the best books on the subject is "Reflections" (or
> > "Reflections II")  by Walter Maxwell.  Get a copy and read it, I
> > guarantee it will open your eyes.  You should probably have your own
> > copy.  New or used are equally good.
> >
> > (2) Along with a copy of "Reflections",  you should have a recent copy
> > of the ARRL antenna book.  A brand new copy is not required. Anything
> > within the last 10 years will do.
> >
> > Do NOT let some inexperienced or ignorant person try to convince you
> > that a SWR above 1:1 will deduct from your signal, this is simply not
> > true. I have successfully used HF antennas at SWRs exceeding 10:1 - the
> > trick is matching the transmitter to the  load.  If you can do that, the
> > antenna WILL radiate.
> >
> > Also, keep in mind that ANY antenna is better than no antenna!
> > Experiment and try different approaches.  Someone suggested folding
> > (bending) the radiating element so it fits into the available space.  By
> > all means try that approach.
> >
> > The suggestion by Glen Zook (on this reflector) to use a "L" shaped
> > antenna 9 by 24 feet is a good one.  Be sure to have a good "ground"
> > connection in the event you are using a single wire antenna.  Having the
> > best ground connection you can manage is critical to good performance
> > for this configuration.
> >
> > Finally,  these suggestions pertain mainly to HF antennas.  Antennas for
> > VHF and UHF have different considerations.
> >
> > - Jim, KL7CC
> >
> >
> >
> >
> >
> > On 10/21/2016 5:01 PM, J Mcvey via ARC5 wrote:
> >> Yeah, where there's a will there's a way! Not to mention that a 24 ft
> >> square has a perimeter of 96 feet and a 33.9 foot diagonal.!.
> >>
> >> Maybe 18ft is an optimal short length for 40 meters?  I was able to
> >> load up to 23 ft of wire on 40. I was testing to find out how long was
> >> too long.
> >> My thinking was once you are below 1/4 wavelenth, it's not really a
> >> resonant antenna anymore, or ar least not a good one.
> >> The E amplitide increases per unit length, so wouldn't longer be better?
> >> Next up: propagation tests?
> >>
> >>
> >> On Friday, October 21, 2016 7:50 PM, Glen Zook via ARC5
> >> <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>> wrote:
> >>
> >>
> >> Run 9-feet vertically and 24-feet horizontally.  Will work very well!
> >>
> >>
> >> Glen, K9STH
> >>
> >> Website: http://k9sth.net <http://k9sth.net/>
> >>
> >>
> >> ------------------------------------------------------------------------
> >> *From:* AKLDGUY . <neilb0627 at gmail.com <mailto:neilb0627 at gmail.com>>
> >> *To:* Mike Everette <radiocompass at yahoo.com 
> <mailto:radiocompass at yahoo.com>>; ARC-5 List
> >> <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>>
> >> *Sent:* Friday, October 21, 2016 6:46 PM
> >> *Subject:* Re: [ARC5] Antenna for small yard
> >>
> >> Please tell me how I'm supposed to fit a 33 foot antenna into a 24
> >> foot yard.
> >>
> >>
> >>
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