[Elecraft] K2 --- Park Portable Antenna

[Ron D'Eau Claire]

As Vic pointed out, a center fed half wave (i.e. center fed "dipole") is
probably the most efficient and easiest to erect, especially on 20 meters
where it's only 32 feet end-to-end. Such an antenna provides a low
impedance, letting you use coaxial feeder if you use a feed line.  

Keep in mind that it does *not* need to be in a straight line. It can be
erected in various ways. For example, if you throw one end over a tree so it
drops vertically to the rig, the other half can run horizontally near the
ground, making a very efficient "vertical". Such an arrangement will be
somewhat directive in the direction you run the horizontal segment near the
ground. 

Optionally you can use feed line and make an inverted "V" 

Skip the coax and use a reasonable length of 300 or 450 ohm window line for
a feeder (just hook one side of the twin lead to the center pin on the
antenna jack and the other side to the chassis ground) and you can use the
antenna on any band from 40 through 10. On 40, where it's only 1/4
wavelength overall, it'll be 1 or 2 dB "weaker" than a full half wave, but
that's pretty darn good. 

On higher frequencies you'll actually see a little "gain". .

Ron AC7AC 

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of k7hbg at dslextreme.com
Sent: Sunday, July 06, 2008 5:38 PM
To: elecraft at mailman.qth.net
Subject: [Elecraft] K2 --- Park Portable Antenna


Hi Vic;
 Your advice of launching a long wire into tree punched my "lets do
something" button. I think I'll take my K2 out to the park next week and try
getting on the air with a tree vertical as you suggested. Twenty meters
should have some life in it and with this in mind, what form would this
simple antenna system take? I have a KAT100 which I could take along to
match it.

Regards, Bob K7hbg




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