Thanks for the input Guy,
Actually, the lengths are just a result of me trying to get this antenna
optimized for 40m with my Yaesu 840 and the MFJ unbalanced tuner. This is my
first HF antenna, and I never intended for it to be a true multibander. And
yes - it never performed well on 20m at all.
Hi Daniel!
I too have a KX1/AT1, and in fact, noticed this issue on the KX1 before I
was even done building the K2. I just hooked the KX1 back up, and I'm
getting nearly the same results.
40m 8.1:1
30m 1.3:1
20m infinity:1
It's been a while since I've used it outside, but I used to hook it up
Dave,
It is of great interest that your KX1 tuner could handle the tuning if
you connected it directly to the balun. Fact is that the KXAT1 range is
quite limited due to only having 3 inductors and 3 capacitors to switch
in and out trying to find a match - the KAT2 has 8 of each and has quite
daniel.pe...@fshsociety.org
To: elecraft@mailman.qth.net
Sent: Friday, January 15, 2010 10:02 PM
Subject: Re: [Elecraft] [OT] High SWR on 20 and 40
Dave,
Thanks for posting this.
I'm going through the exact same exercise with my KX-1 KXAT1 and
Icom703+. Glad to know I'm not alone. The Icom
Dave,
Have you tried putting a dummy load in line and seeing if the tuner will
tune 1:1 with it?
This might tell you if the problem is in the tuner. You could also place the
load further along the coax and see if the problem disappears.
My KAT2 can tune almost anything it seems, but it is
Dave and all,
Are you aware that you can use both tuners in tandem? You can set the
manual tuner quickly for a close match and then let the internal tuner
refine the match.
For instance, you have an antenna that is difficult to match, but you
already have a list of setting for a close match
Of course two tuners doubles the tuner losses. Tuner losses amount to
10 to 15% per tuner, sometimes higher. If you're not folding back power
after the first tuner does its match and it's under about 1.8, don't
bother. There is nothing real to be gained.
If you need both tuners, the real
There is one benefit to a low match at the tranceiver. Most builtin power
meters are only accurate at 1:1. If you're trying to ensure you are qrp
and your transmitter measures output power to maintain that level you need
to ensure the match is correct.
jim ab3cv
Brian,
While all that is true, the operating convenience that is afforded by
using that method can be more significant than the added loss - it all
depends...
An L network usually is a low loss tuner. All the Elecraft tuners are
of the L network type, as are many other 'auto-tuners'
The old
There are many kinds and configurations of tuners, each one having
differing weak spots. There is not a single one outside of military
prices which does not have impedance ranges that are inappropriate for
the particular tuner design. Some tuners use CONTINUOUSLY variable
inductors AND
Dave - If an antenna suddenly changes its behavior, the cause is usually a
broken connection somewhere, or a problem with the feedline, either shorted or
open. So check these all first. It is easy for there to be a break in the
ladder line, particularly if it uses a solid conductor that is hard
Hi James,
Thanks so much for the extremely informative reply! I will dig deep into a
lot of your suggestions later tonight. I think I may have overcomplicated
the issue, so let me see if I can give it a shakedown.
First off, lets forget everything besides 40m. That's really the band I am
It sounds like you have a broken/shorted wire somewhere. For testing, could
You run coax all the way to the antenna and see how that does? If you
Antenna is insulated wire, don't overlook the possibility of a break in the
Antenna itself. With 67 feet of wire, you should get a fairly decent
Dave,
No, you are not an idiot, nor drunk, but you may be confused by the
impedance transformation effects of a feedline.
I suggest you take a look at the ARRL Handbook or Antenna Book chapter
on Transmission Lines, especially the sections dealing with transmission
line matching sections if
), trim the length of
the wire for minimum SWR at your frequency of interest and get on and operate.
Wes N7WS
--- On Sat, 1/16/10, djmd d...@fuse.net wrote:
From: djmd d...@fuse.net
Subject: Re: [Elecraft] [OT] High SWR on 20 and 40
To: elecraft@mailman.qth.net
Date: Saturday, January 16
Hello,
I have been trying to troubleshoot my antenna system, and have been trying
to avoid the dreaded high swr post, but I've run out of ideas, so I'm
turning here.
First let me explain my system. 67' dipole fed by 16' of window line. That's
connected to an Elecraft balun. From the balun,
Dave,
Is that a 1:1 balun or a 4:1 balun. Usually a 1:1 works better, but
whichever balun you are using, try the other one and see what happens.
Do you have an antenna analyzer? or can you borrow one? If so, what is
the impedance at the end of the coax? Both the resistive and reactive
shack is the pi-net in my L4-B.
--- On Fri, 1/15/10, Don Wilhelm w3...@embarqmail.com wrote:
From: Don Wilhelm w3...@embarqmail.com
Subject: Re: [Elecraft] [OT] High SWR on 20 and 40
To: djmd d...@fuse.net
Cc: elecraft@mailman.qth.net
Date: Friday, January 15, 2010, 1:45 PM
Dave
It's the BL-2 switched balun that I have been using, and have tried both
modes. Forgot that detail. I have also tried one of those baluns built from
PVC - can't remember the manufacturer. It's a 1:1 as well. Same results.
No analyzer yet, but I really should think about getting one. Planning on
oh, and yes, I was definitely getting a 1:1 on the KAT2 between the radio and
the dummy load. I put the dummy load in at all points and saw 1:1.
--
View this message in context:
http://n2.nabble.com/High-SWR-on-20-and-40-tp4401077p4402311.html
Sent from the [OT] mailing list archive at
Dave,
If you did not disconnect the KAT2, then please tell us the setup (all
the connections) when you have SWR readings below 1.5.
That may be capable of providing some sort of clue.
73,
Don W3FPR
djmd wrote:
And re: your follow up - all the testing was done with the KAT2. I have
never
The 16 feet of window line makes me wonder if you're not trying to do
a half-size G5RV, but got the top dimensions wrong. It would be 51'
(instead of 67 which is REALLY bad on 20 meters), or a little longer,
say 54' if you wanted to load on 17m and 12m.
My K2/10 and the auto tuner will match
Dave,
Thanks for posting this.
I'm going through the exact same exercise with my KX-1 KXAT1 and
Icom703+. Glad to know I'm not alone. The Icom is able to tune just
fine and when I switch the KX1 does not tune all bands – not on 40M.
The KX1 tuner is optimized for shorter lengths
Dave,
Thanks for posting this.
I'm going through the exact same exercise with my KX-1 KXAT1 and
Icom703+. Glad to know I'm not alone. The Icom is able to tune just
fine and when I switch the KX1 does not tune all bands – not on 40M.
The KX1 tuner is optimized for shorter lengths of
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