[ARC5] Antenna for small yard

Fri Oct 21 23:25:43 EDT 2016

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-j265and for the 18 foot (5.49M) wire it was  6.57-j397which 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>
To: "J Mcvey" <ac2eu at yahoo.com>; "Glen Zook" <gzook at yahoo.com>; "AKLDGUY ." 
<neilb0627 at gmail.com>; "Mike Everette" <radiocompass at yahoo.com>; "ARC-5 
List" <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> wrote:
>>
>>
>> Run 9-feet vertically and 24-feet horizontally.  Will work very well!
>>
>>
>> Glen, K9STH
>>
>> Website: http://k9sth.net
>>
>>
>> ------------------------------------------------------------------------
>> *From:* AKLDGUY . <neilb0627 at gmail.com>
>> *To:* Mike Everette <radiocompass at yahoo.com>; ARC-5 List
>> <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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>

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