[ICOM] ICOM 718 SWR meter

[Gary P. Fiber]

Do you have or access to a good known dummy load?  Something to take the 
antenna reactance out of the picture?
i can tell you what ever the SWR meter reads on the IC-718 is also going 
to be the controlling factor so far as power out is concerned.
Could be an SWR adjustment problem or some other issue on the IC-718.
I generally like to get to a known starting point like a good flat dummy 
load.

Anyway my opinion.

Gary K8IZ
.

On 2/26/2011 4:32 PM, Patrick Schwarz - KB8RTZ wrote:
> Curious if anyone else has checked the SWR meter built into the IC-718
> with the SWR meter of an antenna analyzer such as the MFJ-269?
>
> Here is the setup:
> Antenna - Hustler 6BTV
> Analyzer - MFJ-269
>
> Process of tuning the antenna prior to purchasing the antenna analyzer:
>
> Connected a 25 foot feedline (RG8U) between the antenna and transmitter.
> Per the antenna manual, tuned the antenna on 10m, 15m, and 20m. 30m on
> down did not tune well or at all. Ground radials helped, but not enough
> below 30m. Came to the conclusion that my tuning skills left a lot to be
> desired so invested in an analyzer.
>
> Process of tuning the antenna with the antenna analyzer:
>
> First, reset the trap lengths to factory lengths, then overall tube
> lengths to suggested starting lengths using ground radials. Connected a
> 9 foot feedline (LMR-240) between the antenna and analyzer, manually
> tuned the antenna per the manual. Disconnected the analyzer and tuning
> feedline from the antenna.  Reconnected the transmitter feedline (this
> time a 75 foot feedline (RG8U)).
>
> Checked the SWR at the transmitter feedpoint with the analyzer. The
> results at the antenna with the tuning feedline and at the transmitter
> feedpoint were comparable. Disconnected the analyzer and reconnected the
> transmitter. The SWR meter built into the IC-718 measured relatively
> close results on 10m and 15m. The SWR on 20m was a little higher than
> measured by the analyzer, higher yet on 30m and 40m, and worse yet on
> 75/80m (granted, 75m is not fully tuned yet).
>
> Seems as though one or the other is incorrect. The SWR at the antenna on
> say 7178KHz on the MFJ reads 1.6. The SWR at the transmitter feedpoint
> using the MFJ reads 1.6. The Icom SWR meter reads 2.1 or so requiring a
> little tuning.
>
> Has anyone else noticed these types of results?
>
> Thanks,
>
> Patrick...KB8RTZ...
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-- 
Gary Fiber K8IZ
GROL PG-19-6691 with shipboard radar endorsement
Washington State resident