I don't think so.
The K3 tuner is in bypass. The LP-100A is next in line, followed by the
tuner (no amp yet) followed by the fan dipole. The tuner is showing the
tuned SWR. The LP-100A sees only the tuned SWR and the K3 tuner is off so
it should see the same thing that the LP-100A sees.
The LP-100A and the tuner generally agree (the LP-100A is digital and the
tuner uses crossed-needles, but it's close). The K3 is consistently lower.
73,
Michael / N6MEF
-Original Message-
From: John Gaynard [mailto:jgayn...@columbus.rr.com]
Sent: Thursday, January 01, 2009 11:24 PM
To: 'Michael E Fox (N6MEF)'; elecraft@mailman.qth.net
Subject: RE: [Elecraft] k3 SWR readings seem generous
Isn't the LP100A giving you the actual SWR, not the tuned SWR since the
LP100A is getting current samples from the feedline to the antenna and is
independent of the K3 tuner. The K3 tuner is making the K3 see 50 ohms.
The LP100 is telling you the actual SWR that exists prior to the K3 tuning
it to the 50 ohm. I have the LP100 using it with a SteppIR BiggIR vertical
and also a Gap Voyager vertical for 160m and 80m. The LP100 reads around
1.04:1 on the SteppIR on 40m as does the K3 (shows 1 bar), which is close to
what my old Diamond meter use to read. However, the Gap SWR is around the
2.3:1 range when the K3 (or PW-1 tuner) reads about 1.5:1 or less. I then
realized it was showing me the real SWR, not the tuned SWR.
I think I am correct in this assumption.
John K8WDN
-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Michael E Fox (N6MEF)
Sent: Friday, January 02, 2009 1:18 AM
To: elecraft@mailman.qth.net
Subject: RE: [Elecraft] k3 SWR readings seem generous
I noticed the same thing. My factory-assembled K3 is reading 1.0 SWR while
my LP-100A and tuner both agree on about 1.4-1.5.
Michael - N6MEF
--
Message: 45
Date: Thu, 1 Jan 2009 17:47:04 -0800
From: Mike Scott m...@paxsen.com
Subject: [Elecraft] k3 SWR readings seem generous
To: Elecraft@mailman.qth.net
Message-ID: 7a956b0039b848bd89a04d31855c4...@dbqj5v71
Content-Type: text/plain; charset=us-ascii
I have been working on antennas today and have a puzzle. I am finding that
the K3 SWR indications are unbelievable generous.
With my 40M inverted V fed with RG8X (50 ohm) coax I see that the K3 seems
generous in the SWR indication on tune with ATU bypassed. I have noticed a
slight change in SWR with K3 power setting so the following was taken with
K3 tune power set to 100 watts. If I set it to 10 watts the discrepancy is
greater...
SWR SWR SWR
Freq. K3 VA1 Daiwa
7.00 MHz 1.3 1.922.0
7.05 MHz 1.2 1.921.9
7.1 MHz 1.2 1.981.95
7.15 MHz 1.3 2.262.1
7.2 MHz 1.9 2.602.3
7.25 MHz 1.5 2.882.6
7.3 MHz 1.6 3.322.7
The Daiwa is the CN-101L cross needle meter. The VA1 is the Autek Rx Vector
antenna analyzer. The VA1 does not have a tuned input so it is possible
that it can be fooled by local broadcast stations. I don't suspect this
issue here as there aren't any close by broadcast stations that I am aware
of. The Daiwa and the VA1 tend to agree pretty well anyway. The K3
measurements are the outliers. This antenna on a Tenna Dipper shows
minimal SWR at 7.040 MHz, just where I tuned it a few years ago. The LED
does not extinguish indicating higher than 1:1 SWR at the minimum. If you
look at the numbers, I guess I don't believe the K3, Do you think my antenna
is below 1.6 to 1 across the entire 40M band?
So now on to 20M dipole fed with RG58 (50 Ohm Coax)...
The Tenna Dipper fully extinguishes at 13.805 MHz indicating that my antenna
is bit too long but is close to 1:1 at that frequency.
FreqK3 VA1 Daiwa
13.81 -- 1.12--
14.0 MHz1.11.241.31
14.1 MHz1.11.301.70
14.2 MHz1.11.551.85
14.3 MHz1.21.691.85
RG58 may have some losses on this band so perhaps all of the SWR indications
are generous, some more than others. The dipole is a low one and probably
isn't 72 ohms at the feed point.
Mike Scott - AE6WA
Tarzana, CA (DM04 / near LA)
K3-100 #508/ KX1 #1311
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