Posted by
Craig - AE6RR on
Mar 20, 2012; 7:03am
URL: http://elecraft.85.s1.nabble.com/How-accurate-is-the-K3-SWR-meter-tp7387785p7388256.html
If you have an SWR greater than 1:1, there will be standing waves on the
coax between the K3 and the external SWR meter and the length of the coax
between the two will change the SWR difference and it will vary with
frequency due to the change in wavelength of the piece of coax.
If the SWR is 1:1 (try with a dummy load), the two meters should both read
1:1.
Try a very short piece of coax or a PL-259 to PL-259 coupler between the
radio and the external meter and see if that gets you a closer reading. In
any case as stated below it is the SWR at the final amplifier that counts.
73,
- Craig, AE6RR
-----Original Message-----
From:
[hidden email]
[mailto:
[hidden email]] On Behalf Of Vic K2VCO
Sent: Monday, March 19, 2012 6:59 PM
To:
[hidden email]
Subject: Re: [Elecraft] How accurate is the K3 SWR meter
If the K3's antenna tuner is not set to 'Bypass' then there will almost
certainly be a difference, since the external tuner is reading the SWR
between the output of the internal tuner and the antenna, while the K3's
reading is between the K3's final amplifier and its tuner. This difference
can be very great, because the internal tuner is doing its job!
If your K3 does not have an internal tuner or you have set it to Bypass,
then there may be a small difference due to inaccuracies in the tuners, and
stray inductance and capacity in the K3's output circuitry. You can ignore
this -- I would use the K3's reading in this case because it represents what
the K3's final amplifier is seeing.
On 3/19/2012 6:42 PM, Robert G. Strickland wrote:
> I am pretty new to the K3 world and just getting acquainted with the
> radio. I have a Vectronics Vector 500 antenna tuner with a cross
> needle swr meter. I notice a disparity between the swr readings on the
> K3 and on the antenna tuner. So, how accurate is the K3 swr reading? I
> can imagine that the Vector cross needle reading is not particularly
> accurate, but I don't know that for fact. I don't have access to a
> high quality swr bridge, so I'm trying to figure out which reading to
trust.
> Any comments are much appreciated.
>
> ...robert
--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/______________________________________________________________
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