[Elecraft] [K3] SWR - Numerical Indication

[Bob McGraw K4TAX]

Yes, the K3S SWR display can show a 1.0:1 value.  But in my case,  it 
does not exactly agree with another instrument in the feed line system. 
     As to why you are showing two different values, as minute as they 
are I might add, you are measuring 2 different places in the feed line. 
   In my thinking, it is physically impossible to put two  SWR bridges 
in the same place electrically.

In theory the SWR on a given line should be the same at all places, but 
maybe not since there is loss of some minute value in the line.      
Since you are measuring on antennas, common mode current, may be the 
contributing cause.  Difference in measurement calibration, may be a 
factor as well.

VSWR bridges are calibrated with some specific value of load. Ideally, 
it is 50 ohm non-reactive, but it could be 49 ohms or 51 ohms or some 
other value.   Just because a load says "50 ohms" on the label is no 
real indication that is actually fact.    To that end, I have 3 dummy 
loads which are "50 ohm" loads according to the label but none are not 
true 50 ohm loads.    I do have a Celwave load that says 50.5 ohms on 
the label and measures 50.5 ohms per my General Radio bridge.    The 
others are +/- something, but good enough to evaluate a ham transmitter 
or amplifier.

Frankly, a difference between 1.1:1 and 1.0:1 won't make any realistic 
difference in any form or fashion other than to appease the operator.

73

Bob, K4TAX



On 7/27/2018 9:58 AM, Dick Dickinson wrote:
> I've noticed that I'm not showing a reading of less than 1.1:1 SWR on my
> antennas per K3 SWR Numerical Readout.  K3EZ will record 1.0:1 SWR in band
> sweeps.
>
> Can the K3(S) Numerical Display show 1.0:1 SWR?  If so, is there a likely
> reason why K3EZ will show 1.0:1 while my K3 will only go as far down as
> 1.1:1?
>
>
> Dick -  KA5KKT
>
>
>
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