I would say try it with an analyser, see what you get, can't hurt
may help you resolve your problem

Al
----- Original Message ----- 
From: "Daniel Paul Perez" <daniel.pe...@fshsociety.org>
To: <elecraft@mailman.qth.net>
Cc: "Daniel Paul Perez" <chesapeake1...@post.harvard.edu>
Sent: Tuesday, December 22, 2009 10:21 PM
Subject: [Elecraft] [KX1] Help sought KX1 high SWR on 40 and balanced antenna


Hi all!

I’m having a hard go of it with Elecraft products.  I had a bad
experience with a K2 that just never worked right at my QTH.  Gary at
Elecraft looked at it twice and said it was extremely well built and an
excellent sounding radio.  Not for me.  I finally sold it – I never ever
heard a clear voice on it.

Subsequently, I purchased an Icom703Plus and it is connected to a Cobra
Senior Ultralight up 55-60’ at one end 45-50 at the other with center up
about 40-45’; 450 ohm ladder line runs about 1’ foot through a casement
window; to a Balun Designs 4:1 current balun; to a 3’ coax with 239 –
239 connectors. The radio tunes up on all bands with respectable swr and
power.  I turn it on and I use it – CW, LSB, USB.  Good reports and work DX.

Though having had really bad luck with a QRP K2 I really enjoy reading
about Elecraft products and reading this reflector.  There are many
really bright, helpful, engaged and kind folks here.  So … I decided to
go it again with a KX1.  KX1 was built by Don Wilhelm in July 2009 and I
have no doubt it is built extremely well.

When I hook the KX1 to the same antenna using an amphenol 239/BNC
adapter e.g. Antenna setup is KX-1 | bnc/239 converter | 3 feet coax 239
both ends | Balun Designs Current Balun 3Kw model 4113t | 450ohm window
ladder line | through casement window | Cobra Ultralite Sr. it is
getting respectable power and swr on 80, 30 and 20.  Though 40 will
throw a high power value and r9.9.  My first thought is there’s
something up with the KX1 – I’m still not sure.

Examples:

Before with Antenna I was getting:

3 525 p3.5 r1.1
7 025 p6.3 r9.9
10 112 p4.5 r2.5
14 025 p3.0 r1.6

With 50ohm dummy load at the end of the 3 foot coax (this is the only
coax in the equation both scenarios – previously goes into balun), I get:

3 603 p4.2 r1.0 ||||.||
7 125 p4.2 r1.0 .
10 145 p5.5 r1.0 .
14 025 p3.5 r1.0 ||||.||

I have a Diamond SX-200 meter and a Tokyo Hypower HC 200AT auto-tuner in
addition to the KXAT1 and the Icom’s internal tuner.  So I set out to
try to understand this antenna’s properties e.g. un-tuned native swr,
forward power and reflected power.  I tried turning ATU to CAL and
measuring SWR on the diamond meter on all 4 bands and it is pretty much
all over the map – it’s also hard to manually Cal the meter without
being able to key down.  I tried this with the KX1/HyPower as well and
saw swr’s in the 1’s, 2 and 3’s and sometimes higher.  In both cases the
external tuner or meter were between radio and balun.  I do not have
something right with the KX1/Hypower my though understanding is that I
set menu KX1 ATU to CAL to turn off tune, press buttons to ATU or key
down and press tune on HyPower.  I got a very inconsistent set of
results with the HyPower.  I thought of using an analyzer but am told
the Cobra Senior is really difficult to analyze with something like the
MFJ259/269.

  I tried connecting just one side of the Cobra Sr. to the HyPower wire
lead and was amazed at the magnitude of difference in sound – the KX1
simply came to life crackling and buzzing with all sorts of CW – really
astounding.  Was fine with coax, but simply amazingly louder with the
long wire.  Trying to tune the wire with KX1/HyPower gave SWRs in the
4s, 5s, 6s.  Tried the other wire as well with same result.

I’m genuinely trying to figure out how to figure out what and if there
is a problem with the Antenna.  I’m also trying to figure out what is up
with the KX1.  Dummy load yields good power and SWR 1.0.

Before I decide to hastily part with the KX1 and call it quits with
Elecraft – I thought I’d ask for some help and guidance to help me
understand how to make this antenna better or to understand its native
properties and to be able to turn on an Elecraft radio / this Elecraft
radio, use it, hear it and have no issues.

Thanks for your help.

Best,

Dan
AD1P
chesapeake1...@post.harvard.edu


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