[Elecraft] Longwire with K2/KAT2/BL1
Ron D'Eau Claire
rondec at easystreet.com
Thu Jun 3 17:54:01 EDT 2004
Did you model it over a real earth? It should be darn near omni-directional
on any band below 14 MHz. Be sure you are looking at the pattern at the
right elevation. It'll be a very high-angle radiator on either 40 or 20.
(You need to get up between 30 and preferably closer to 60 feet for good
low-angle radiation on 40. 30 feet is preferable on 20 meters). At 10 feet
the gain will be about 6 dbi or so, but straight up on 40 meters. It'll be
closer to 0 dbi down at 20 or 30 degrees above the horizon.
The buddipole will have higher losses in general. It's an inescapable effect
of ohmic losses in the system. That doesn't mean that it won't get "out",
just that it won't radiate as efficiently as a longer antenna. And, oriented
vertically, it might have as much or better gain down at low angles of
radiation. Where it'll come up "short" if used vertically is very little
high angle radiation for short skip.
On 20 meters a 100 foot wire will show a number of lobes due to it's length
but with the antenna only 10 feet up they will all be at 45 degrees or more
above the horizon - not much use for anything but short skip. At longer
distances where the directivity becomes important the gain is well down and
the pattern nearly circular again.
80 will be like 40, only moreso<G>. Virtually omni-directional with a huge
lobe straight up that will do well for short skip.
I'd feed it against a 1/4 wave counterpoise No need at all for a balun.
Ron AC7AC
-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Daniel Reynolds
Sent: Thursday, June 03, 2004 2:23 PM
To: elecraft at mailman.qth.net
Subject: [Elecraft] Longwire with K2/KAT2/BL1
I was doing some propagation modeling for my buddipole antenna using
ICECAP/VOACAP AREA programs,
=====
My questions for the list...
How would you attach this 100 ft wire to a K2 with KAT2 and BL1 (balun
mini-kit)?
Would use the balun or would you leave it out?
Would you use a counterpoise? If so, how long?
=====
For those of you interested - it looks like that a 100 ft wire (at 10 ft)
running NE to SW would give me a better presence to the NE and SW on 80m
(amazingly... not broadside NW and SE), and it would do a lot better than
the buddipole does on 20 and 40m (only the buddipole might go up quicker
than this antenna).
If the 100 ft wire performs well, and compares favorably to the computer
modeling, then I may be running a 200 ft wire for Field Day. The 200 ft wire
running NW to SE would drive my QRP signal on 80m clear into New England
(from Oklahoma City) in the evening. It would also do a great job on 40 and
20.
72/73,
Daniel / AA0NI
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