[Elecraft] K2 and wire antenna

[Ron D'Eau Claire]

It's very hard to say, Jim, because that sort of antenna will show a huge
range of possible impedance values at the transmitter depending upon the
feeder length. An unmatched feeder like that acts as an impedance
transformer based on its length. That's why you so often see comments like
"change the feeder length if the tuner can't find a match". (I suspect most
people who suggest that never tried to figure out what to do with excess
balanced line, even "twinlead"!) 

Another approach many use is to add a 4:1 balun at the rig. Or switch a
balun between 1:1 and 4:1 (Elecraft makes such a balun whose ratio can be
changed by throwing a switch). That often does the job because it does the
same thing as changing the length of the feeder: the impedance the rig sees
is different and, hopefully, within in the tuning range of the ATU. 

Your MFJ tuner has a much wider matching range than just about any other
design. That's the good side of a T-network tuner. (The negative side is
that it can be very lossy if not adjusted according to the instructions or
if it must match a very low impedance. With your 40 meter antenna, the
impedance isn't likely to be low enough to be an issue on any band from 3.5
MHz up. ) 

Elecraft uses an L-network which is also very, very good, and very low loss
but it doesn't replicate the whole range of your T-match network. So it's
possible it may not provide a good match on ALL bands without providing a
balun or changing the length of the feeder. 

Ron AC7AC

-----Original Message-----

This is a test message and a question.  If the message gets through, that 
part works fine.  Now for the question:  My current QTH is a city lot that 
has several large oak trees in the back yard.  The trees have been there 
over 30 or 40 years and I will not be able to do much more than trim a very 
few limbs that get too close to other structures.  My HF antenna at present 
is an inverted V configuration hung from one of the trees at about 40 feet 
off the ground (also the yard is not level, there are several slopes) and 
the end points tied to another tree on one side of the yard and a fence on 
the other side.  The antenna was cut for 40 meters.  The feed line is an 
unknown length of 300 ohm television twin lead coming into the attic then 
through a closet to the radio.  My current radio (not an Elecraft) has an 
MFJ-941B tuner between the antenna connection and the actual feed line.

Would the K2 with an internal ATU be able to work with this antenna/feed 
line combination?

Thank you,
Jim  KD5VXH