Tom and all,
One of the KX2 Field Testers found that a 58 foot resonator and a 26
foot counterpoise worked well on 80 through 10 meters.
I use half those lengths for 40 through 10 meters.
No feedline, both the radiator and the counterpoise are connected
directly to a BNC to Binding Post adapter on the KX2.
The direction of the counterpoise does not make a lot of detectable
difference. Antenna modeling may show some difference, but working
quickly in the field may not allow you to set up the "perfect" situation
- use what you have available.
The KX2 internal tuner is a wide range tuner that might even be able to
match a metal window frame or the proverbial "bedsprings".
Let's face it, this is a compromise antenna that can be thrown into a
tree and give us the opportunity to make QSOs in the field. For home
station use, a proper antenna up in the air will be better.
73,
Don W3FPR
On 9/8/2018 9:50 AM, Tom McCulloch wrote:
This is probably NOT what you are looking for but it's about random
length antennas...it goes back to Jan 29, 2017.
hope this helps:
I'd call an ad-hoc antenna that works on multiple bands with an ATU a
"Kinda-Random Antenna" (KRA). (Apologies to linguistic purists.)
A simplified definition might be:
A. long enough to work within the maximum limits of the ATU's
L-network on the lowest band used
B. presents a reasonably low impedance on all bands used (e.g.,
doesn't look like an end-fed half-wave)
ATUs have limited monotonicity and granularity, as well as stray
impedances, so in practice there is a third criteria:
C. tunable on each band used despite specific L-network idiosyncrasies
This third criteria is the hardest one to predict for a given ATU
design, as the idiosyncrasies vary with PCB layout and actual component
values. They may only impact the highest bands, or for a particular
antenna, the bands on which Q is the highest. For our ATU designs, we
try to minimize strays and keep the network monotonic by using tightly
toleranced capacitors and toroidal inductors.
While a wide range of wire lengths will meet the requirements of a "KRA"
in the field, we've found from experience that something in the 25'-28'
range works on all bands from 40 meters up, and roughly twice this for
80 meters up. Since it's impossible to predict the effect of ground
losses, obstructions, deployed wire angles, etc., you may occasionally
need to add or remove wire to obtain resonance on all bands used.
73,
Wayne
N6KR
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
