[Elecraft] Best antenna for K2

Thu Oct 16 21:39:01 2003

Mike,

At the International Lighthouse Weekend, and again for a special event 
station at the Harvest Faire a couple of weeks ago, I used some Windom 
antennas, also called Off-Center-Fed antennas.  The dimensions are 1/3-feed 
point-2/3.  I have one 135' for 80, one 67' for 40 and one 46' for 
30.  They cover even harmonics, but the 80 and 40 ones will work on 17 and 
12 with an antenna tuner.  The 80 meter one has a real tiny 1:4 balun In a 
plastic box good for 100 watts which is in the antenna and it is fed with 
RG58.  The other two are fed with 300 ohm ladder line with a low power 
balun on the ground then coax to the rig.  One thing not really appreciated 
by other than users of Windom antennas is they are very broad band.  If 
over 30' high, they have SWRs of generally less than 1.7:1 over all the 
fundamental and even harmonic entire bands and usually less than that, so 
you don't really need a tuner.

Another portable antenna worthy of note is a W3EDP antenna.  It consists of 
85' of wire and a single counterpoise of 17' laid on the ground.  You can 
throw one end over a tree and bring down the rest to the ground as a 
sloper.  It needs an antenna tuner.  I use a 1:4 balun between the antenna 
and counterpoise and a short length of coax and tune it with my KAT2.  The 
W3EDP antenna is written up in "Practical Wire Antennas" by John D Heys 
G3BDQ, available from ARRL.  You can also feed it with a short length of 
300 ohm ladder line and hook it directly to the KAT2 BNC with or without a 
balun.  Deduct the length of the ladder line from the 85' and the 17'.

For feed lines, I have made up some using a twisted pair of Teflon 
insulated, stranded #24, which is light for portable operation and is 
rather strong.  It has an impedance of about 200 ohms, which means you can 
feed a Windom antenna which has a nominal 200 ohm impedance at the feed 
point.  Hook the ends to the BNC on the KAT2 with or without a balun, and 
you are in business.  I got several hundred feet for practically nothing 
from someone on one of the reflectors whose name I can't recall at the 
moment.  Put out a call.

I believe most of the backpackers on the AT use a dipole.  One of my 
friends has a sea going canoe, he and paddles ashore and puts up an 
inverted V for 40 with a 20' mast.  He uses a RG-174 feed line.  Works.

Lots of possibilities.

At 03:56 PM 10/16/2003, Michael D. Heit KD7YLA wrote:
>Hi folks,
>  I want to use my K2 primary for back packing in the mountains of 
> Montana, Idaho and Washington, and next year, in Alaska. I want the best 
> antenna for that type of operation. Primary use would be QRP, DX. 
> Secondary would be SSB. I have seen a few online, and am leaning toward 
> one of the "portable type" with the bag and all. I was wondering , since 
> there is a lot of activity about just putting up a long wire, if this 
> would be as efficient as one of the other types?  I should think a 50 
> foot piece of wire would suffice? You guys and gals out there on this 
> list are experts at this, may I be privileged to pick you collective 
> brains about this question?
>Thank you very much for any and all replies I will get. By the way, my 
>"normal" rucksack ( an A.L.I.C.E. Large with all gear for extended hike of 
>minimum 2 weeks) weighs in at about #80 start of trip, may get to #60 by 
>end of 2 weeks. This predicates taking 2 batteries, and I am exploring the 
>use of a solar panel to keep top charge of one battery while using another.
>
>--
>73, de Michael Heit KD7YLA
>"Real Hams do it at a high frequency"
>
>
>---
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73, Chas,  W1CG
K2 462b, 3571 