Hi Bob--This is the most simple and accurate explination of the problem
and solution yet posted. Your direct post to me said many truths.
Ten-Tec forever!!
73, Ariel, K4AAL
Robert McGraw wrote:
>
> After seeing much discussion on SWR indications regarding TenTec
> equipment I couldn't sit by and not put in my thoughts.
>
> SWR is a relative value which is determined by comparing 2 values.
> Hence, Standing Wave RATIO. The TenTec radios do not have provision for
> setting the forward meter calibration. Hence they are calibrated at
> typically 100 watts output. At that point the reflected (SWR) value is
> close to correct. At lower forward power, the SWR value indicated is
> less than actual. Situation normal.
>
> Regarding SWR meters reading different values at different points in a
> transmission line, i.e. radio and tuner. This is most commonly caused
> by current flowing on the outside of the coax between the tuner and
> radio. In most cases it is small enought not to cause operational
> concerns but will make meters read slightly different. Adding a ferrite
> choke with 5 to 7 turns of coax in line between the tuner and radio will
> most often correct the concern.
>
> The most accurate method of determining SWR is to measure forward power
> and reflected power and then calculate the SWR ratio. The cross needle
> meters do a good job of doing this for you.
>
> Happy New Year and happy SWR computing.
>
> 73
> Bob K4TAX
>
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