SWR Quandry

[WB8JBG]

I have a Kenwood 940 S with auto tune. I am putting up a new beam. THe SWR when using an out board meter shows a SWR of 1.5 and 50 watts out. If I use auto tune the SWR on my rig shows 1.5 and wattage of 150, but at the same time the out board meter shows an SWR of 5 to 1 and watage of 150. Am I just tuning the the out board meter or is the rig showing the correct SWR and power. Got me stumped. TNX

[K4ICL]

Try connecting the external swr bridge with a different coax cable.

Worth a shot...

AL

[KE3WD]

When using an internal auto tuner, you must rely on the internal metering.

This is because the auto tuner gets inserted between the power amp of the rig and the antenna jack.

The antenna output jack at that point will become something other than a 50 ohm output as the internal tuner inserts L and C to come up with a match.

Placing an SWR meter after that won't tell you anything of value really.

The antenna tuner, properly called an antenna matching unit, and the antenna must be viewed as one -- the antenna system -- at that point.

Only metering resource you have when using an internal tuner is the metering on the rig itself.


73,

[HAMNERD]

TURN OFF AUTOTUNE IF YOU CAN AND ADJUST THE SWR WITH AN EXTERNAL OR INTERNAL BRIDGE, BUT GET A TRUE READING WITHOUT THE TUNER. YOU WILL NOTICE A DIFFERENCE WITH THE LOWER SWR AND NOT JUST A TUNER TELLING THE RADIO WHAT IT WANTS TO SEE.