> >What would you suggest in it's place given:
> >
> >1. Less than 100 feet long.
> >2. Covers 1.8 - 30 Mhz.
> >3. No antenna tuner.
> >4. Feed it with coax.
> >5. Put it up in an afternoon with a couple of poles.
> >6. $200 or less.
> >
> >Thanks,
> >Barry
>
> I'd eliminate requirement #3. Then, I'd put up a 100' doublet, and feed
> it with open wire or 450 ohm transmitting twin-lead. Run the open wire
> right to the house, then use a balun before going inside. Use the
> shortest possible run of solid dielectric RG-8 / RG-213 to get to the
> tuner. Some transceiver auto-tuners can handle this antenna directly.
>
> 100 feet is a bit too short to cover 1.8 MHz. But, as long as it is high
> enough, this antenna will do OK for the other bands.
> Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@radio.org
> I like AA4LR's solution, though I'd try it without the balun at the
>house first, and I'd droop and/or dogleg as much wire as possible off the
>ends and give that tuner a fighting chance on 160m!
>73, DavidC AA1FA
I can contribute a suggestion. Bill and Dave are right about a multiband
doublet. They can and do work well.
Make a doublet and feed it in the center with ladder line. Transition the
ladder line to shielded-parallel lines where it enters the shack (2 pieces
of rg-58 - connect per ARRL antenna book). Connect to an inexpensive tuner
with internal balun similar to MFJ 949. Sorry, but you've got to have a
tuner!
Now, here's the neat part. No ground radials will be required. Also, you
can greatly extend the doublet's low frequency resonance by capacitively
end-loading it, the most efficient way of loading an antenna.
Connect 25 foot or so 'tails' to each end of the doublet and let them hang
down. Attach another cross piece, as long as you have room for, to the
bottom of each tail, such that the composite, end-load attachment looks
like an upside-down "Y". Attach and tie off tag lines to spread and secure
the tails. This way, your tag lines extend and become part of the
capacitive end-load. Terminate the copper and switch to rope at least 8
feet above the ground for safety.
You will be amazed at how much loading you can achieve.
You will have many lobes of covereage with good gain on the higher bands,
and even have some coverage off of the ends, thanks to the tails. On 160,
it will be almost omnidirectional, and good for close-in contacts ('cloud
warmer').
An attempt at an ASCII art illustration follows:
**************||****************
* || *
* || *
* || *
* * || * *
* * || * *
* * * *
I have a friend, Mickey, KU4KW, who simply added coils, wound on PVC forms,
to the very end of his short doublet, and can load it in many places on
160M.
Have fun!
--...MARK_N1LO...--
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