Re: [K3] SWR - Numerical Indication

Posted by John Oppenheimer on Dec 02, 2018; 11:55am
URL: http://elecraft.85.s1.nabble.com/K3-SWR-Numerical-Indication-tp7643839p7646730.html

Hi Dick,

An EZNEC and SimSmith model of the on ground 1/4 wave vertical:
https://www.kn5l.net/images/SS-KA5KKT-vertical.png

SimSmith R1 represents ground loss, the value set to establish a 50 ohm
load at the transmitter, G in SimSmith.

According to the models, the 7 to 7.3 MHz SWR is a little below 1.3.

A flat measurement using the K3 SWR meter seams reasonable. My
suggestion is to use a Antenna Analyzer to measure the antenna and system.

John KN5L

On 12/2/18 12:16 AM, Dick Dickinson wrote:

> I have a full-size monoband vertical for 40 meters.  Simple architectural
> aluminum tapering from 1 ¼” (?) in 6’ telescoping sections.  The radial
> field is designed to provide a 50 ohm match at the feed point…12 – 13’+
> radials.  It is fed directly…no matching device with RG-213 from the remote
> antenna switch about 50’ away at my tower.  The coax from the rig to the
> remote antenna switch is estimated to be ~ 50’ in length.  A lot of the time
> running K3EZ to sweep the band (typically 20 watts), it will indicate a
> 1.0:1 SWR from 7.0 MHz to 7.3 MHz in 20 kHz steps.  Occasional deviation
> from one K3EZ run to another might be due to variations in moisture content
> of the ground or less than perfect connection to the vertical…an uncommon
> situation.  The K3 shows the same readings.
>
> Is this 1.0:1 SWR across the entire 40 meter band curious or remarkable?

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