[ARC5] Antenna for small yard

[AKLDGUY .]

Hi Jim

That's some good advice. My initial inclination was to use 300 ohm TV
ribbon, which I still think is a good idea. I'd like to use it if possible.
I built a tuner consisting of a coil, link fed with 2 turns at the center,
and with a BCB 3-gang capacitor across the coil as a split-stator
capacitor. This tuner worked very well. With two 560 ohm resistors in
parallel across two taps on the coil, I was able to put 5W into the
resistors (they got too hot to touch in 3 seconds). I have no doubt that
the same would happen if the taps were connected to 300 ohm ribbon with the
resistors out at the end of the ribbon. So I could easily match to a 300
ohm antenna.

73 de Neil ZL1ANM


On Sat, Oct 22, 2016 at 3:10 PM, Jim Wiley <jwiley at gci.net> wrote:

> 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
>
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