Is there a way to read the L and C values of the ATU and/or to manually set them?

rssutton9 · April 2021

I have a 6400 feeding a 132 ft. end-fed antenna. Using the ATU it takes several attempts on 75 meters to get a good match. I'd like to lift the hood and see what the atu is doing.

Mike-VA3MW · April 2021

@rssutton9 What version of SmartSDR are you using?

Also, don't for the internal tuner is only designed to do an 3:1 SWR or less reliably. Don't confuse the ATU in the 6400 with a proper antenna tuner that can far exceed that operational range.

73

John KB4DU · April 2021

This is a common limitation of internal tuners. They are intended to support operations with an antenna that is resonant in the band but is being used at a frequency slightly off the resonant point. An end fed antenna could have a feedpoint impedance of 3000 ohms or more (60:1). Its going to need an impedance matching transformer.

Mike Steventon · May 2021

On page 13 of the 6400 and 6600 user manual it quotes:

8.3 - 300 Ohms (80m – 10m) 6.7 - 150 Ohms (160m and 6m)

-for the atu range.

I find it quite good on my long wire, but you cannot beat a decent manually operated Palstar AT2K to have control over the rubbish I **** in my back garden!

rssutton9 · April 2021

Thanks. I wasn't aware of its limitations. I use v3.2.31.

Mike Steventon · May 2021

Is there a way to read the L and C values of the ATU and/or to manually set them?

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