Vic,
Before you write off truly balanced tuners in favour of the T-network +
balun g, it would be interesting to measure and compare the current in
each wire of the feeder (while transmitting a carrier) when using the
Matchbox and then the T-network + balun?
73,
Geoff
LX2AO
On April 05,
I am not sure I know how to do this. I have a device that I made
http://www.qsl.net/k2vco/sniffer/rfsniffer.html
to measure current but it gave me anomalous results when I tried it on the
matchbox. I
found that when I measured the currents about 4 inches from the matchbox they
were equal,
but
Vic et al,
The currents on a particular wire of a two wire feedline, will always
be the vector sum of differential current and common mode current.
This is not the same thing as forward and reflected, which are both
expressed in the differential current. The tuner will be able to
control the
Did the Sniffer give you similar anomalous results when you were using the
T-network + balun? Also I assume that the indoor run of 450 ohm window line
well clear of any object which could affect it.
I suggest that we go off List should you like to discuss this further.
73,
Geoff
LX2AO
On
I use a fan dipole as well (40, 20 and 10), and IIRC from modelling it,
putting a 17m wire in the mix really messed up the match. You might want to
try removing the 17m dipole and see if there's a better match.
Barry W2UP
--
View this message in context:
creative about placing my dipoles closer to
the house and yet out of sight. I am open to any reasonable ideas.
Dave - KO4KL
-Original Message-
From: Adrian [mailto:vk4...@bigpond.com]
Sent: Wednesday, April 04, 2012 10:51 PM
To: 'David Stratton'
Subject: RE: [Elecraft] K3 power reduction due
Adrian,
I've been looking at putting up an OCF antenna to replace my 102' doublet
fed with ladder line. Can you tell me what frequencies on 80 through 10
meters your OCF antenna is resonant? Also, how much of each band can you
cover with less than 2:1 SWR? I'm interested in the CW portions of
Speaking of balanced lines and tuners, I recently did an experiment that
surprised me.
I have a dipole fed with 600-ohm open-wire line (and some window line indoors).
I usually
tune it with a Johnson Matchbox, a fully balanced link-coupled tuner.
I was lucky enough to get my hands on a
Vic,
Where was the frequency of the GDO with respect to the band the tuner
was set to? If it was below the band of interest, I would expect
something like that - the T-Network is a high pass filter.
73,
Don W3FPR
On 4/5/2012 12:28 PM, Vic K2VCO wrote:
Speaking of balanced lines and tuners,
One related question, when speaking of the efficiency of a balanced
feedline + balun and tuner, what would be a best/worst case scenario for
the loss introduced by the balun+tuner? Would loss vary significantly by
frequency for a nonresonant antenna? I'm trying to develop an intuition
about the
All the tests -- signal comparison and noise tests -- were done on the same
band, to which
the tuner was tuned (40m).
On 4/5/2012 12:23 PM, Don Wilhelm wrote:
Vic,
Where was the frequency of the GDO with respect to the band the tuner was set
to? If it
was below the band of interest, I
] On Behalf Of Matt Murphy
Sent: Thursday, April 05, 2012 12:53 PM
To: d...@w3fpr.com
Cc: Vic K2VCO; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 power reduction due to high SWR
One related question, when speaking of the efficiency of a balanced feedline
+ balun and tuner, what would be a best
73, Ron AC7AC
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Matt Murphy
Sent: Thursday, April 05, 2012 12:53 PM
To: d...@w3fpr.com
Cc: Vic K2VCO; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 power
April 2012 5:53 AM
To: d...@w3fpr.com
Cc: Vic K2VCO; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 power reduction due to high SWR
One related question, when speaking of the efficiency of a balanced
feedline
+ balun and tuner, what would be a best/worst case scenario for the loss
Dave,
The KPA3 will throttle back power at or above the SWR = 2.0 point.
Actually, I am not certain about the K3/10 - it may or may not reduce
power above SWR = 2.0,. but I would suggest that your goal for antenna
tuning be less than SWR = 2.0.
I you have resonant antennas, then it should be
It all depends on just what he means by 72 ohm cable TV coax.
If it's the low quality coax used around your TV's, you might be right.
But if it's the 1/2 CATV hardline or the smaller drop cable, the loss
will be much less.
These last two are quite good and have very low loss. I have used just
If I have to use your antenna, then my move would be to replace the 250'
of75 ohm coax with 250' of 450 ohm ladder line, check the fan dipole legs
are exactly the same to provide a balanced load.
You're on target about loss in the feedline, but ladder line is not a
good move here.David has
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