[Elecraft] [KX1] KX1 | KXAT1 ATU questions

[Bill K9YEQ]

Daniel,

A half wave end fed at 40 meters will have extraordinarily high impedance.
Shorten it and you find the KX1 will tune.  The suggestion to use an antenna
analyzer may be a very good option as well.  Then you will know.  There
isn't enough tuning range in the tiny KX1 auto tuner.  If you look through
the archives, you will find some good suggestions from Wayne.


73,

Bill
K9YEQ


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Daniel Paul Perez
Sent: Sunday, January 03, 2010 8:53 PM
To: elecraft at mailman.qth.net
Cc: chesapeake1787 at post.harvard.edu
Subject: [Elecraft] [KX1] KX1 | KXAT1 ATU questions

My KX-1 has KXB3080, KXAT1, KXPD1 options.  I am having trials and 
tribulations with the KXAT1 tuning my KX-1.

My configuration was Cobra Senior Ultralight up 60-66' at one end 45-50' 
at the other with center up about 55-60' | 81 feet of 450 ohm ladder 
line runs that runs about 1' foot through a casement window | Balun 
Designs 4:1 4113t current balun | 3' coax with 239 - 239 connectors 
[703+] OR an amphenol 239/BNC adapter [KX-1].

In this config my Icom 703Plus tuned all bands and forward power was a 
bit diminished.  The Elecraft KX-1 would not tune 40M only.  KX1 is 
getting respectable power and swr on 80, 30 and 20 and 40 will throw a 
high power value and r9.9.

Getting some advice from this reflector (Thanks to Dale - WC7S in WY) 
and the antenna manufacturer I then switched out the 3 foot coax with a 
25 foot coax between the balun and transceiver.

In this config my Icom 703Plus tunes all bands at near SWR 1.0 and 
forward power is exactly at what is set.  The 703Plus works like a champ 
and even better in this config.  Now the Elecraft KX1 has high SWR r9.9 
on 80, 40, 30 and reads between r3-r5?? on 20M with respectable power 
levels on all bands.  I would have thought the KX1 to perform better as 
well?  Now the 703 is perfect and the KX1 is down on all 4 bands?

Could someone help me understand why this might now be?

I realize the KX1 tuner is smaller capacity than the Icom internal tuner 
- but this antenna configuration is quite respectable.  I read many 
anecdotes of the sorts of "I threw a wire up in a tree with my KX1 and 
it tunes and works lots and lots of countries."  This isn't exactly 
throwing a wire in a tree but a fairly standard antenna setup.  Is there 
not enough overall power from the KX1?

I put a call into Elecraft before/at the holiday and they are getting an 
answer for me on my previous question as to how to get the KX1 to send a 
continuous wave when the KXAT1 is in bypass for the external tuner.  It 
appears to me that it sends dits or dahs when ATU is set to external 
tuner ATU == CAL.  I would try to study the situation more with the THP 
HC200-AT autotuner but I'm unclear at the moment what the theory/design 
is with the KXAT1 in bypass mode.

I thank you for your advice and thoughts in advance.

Dan
Ad1p


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