[Antennas] Portable antenna suggestions

Wed Dec 30 22:26:16 EST 2015

Long before these existed, I built many homebrew
end fed half waves. The problem for you is that
you probably don't have the components you need
on hand, so you're back to the time problem.
Possibly order the antenna and have it shipped
directly to your destination.
What you need (for 20 meters) is a coil of around
2.5 uH, adjustable by clipping onto individual
turns. You can wind your own coil if necessary.
Use the ARRL handbook formula for inductance.
You also need a capacitor of about 50 pF rated
at 500V. If possible, bring several values,
like 39, 43, 47, 51, 56, 62, 68 pF. Dipped micas
work well. In a pinch, you can make a
capacitor from a piece of coax. At 32 pF per
foot, you need a foot and half. Start with the
coax long (say 2 feet) and select the turn
on the coil that has the lowest SWR on 20 meters.
If it is not 1:1, then trim a little off the
coaxial capacitor and readjust the coil. Repeat until you
get to 1:1. The capacitor connects between
the shield of the feedline and the antenna.
The coil connects between the center conductor
of the feedline and the antenna. It is desirable
but not essential to make the feedline a multiple
of 35 feet for least RF in the shack issues.
Good luck.
73
Rick N6RK
On 12/30/2015 5:26 PM, Tim Billingsley wrote:
> On Dec 30, 2015 6:28 PM, "Richard Karlquist" <richard at karlquist.com> wrote:
>>>> http://www.lnrprecision.com/endfedz/
>>>> ---
> Looks pretty cool!
>> Anyone have plans for building one?
>> We launch in 5 days and 3 of those are weekend & holiday I don't imagine
> they could get it here except at considerable added cost to me. Not looking
> to bolster Fred Smith's account that much.
>> Just about to the point of throwing the Pixie Ii, a roll of speaker wire
> and the old speed-up in the suitcase and not sweat it. Minimalist QRP LOL
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