General block diagram

This is NOT A TRUE automatic antenna tuner, but this can be useful for semi automatic adjustement of long wire or vertical antenna in portable operations on low bands, or for magnetic loop automatic tuning.

Motor is ~ 3 rpm low voltage DC, and CV1 , air variable, with no ends of strokes.

First circuit: Automatic direct reading SWR meter and Wattmeter …

Old revision 2 circuits picture

Shielding of circuits is necessary.

Second circuit, If you want to make an "Antenna Tuning Unit"

With supply 13.8 V, if your SWR bridge detectors output exceeds 11 volts, you have to increase the supply voltage (up to 30 volts) in order to have at least about 3 volts more in supply than detectors voltage. You can also change the bridge design (with EXCEL sheet)

 

SWR Bruene bridge picture

Front plate & meter scale

Download file for PCB's and schematic diagrams:  SWR+ATU F1FRV.zip 

Link to SWR Bruene bridges, calculations and EXCEL design sheet

Meter scales can be made with F5BU’s freeware “GALVA” available on the net, or in LINKS pages.
Nota: GALVA can import files created with WB6BLD’s software “METER” 

In download file there are example files for GALVA SWR meter scales

That’s All Fox ! ! ! !

Dominique - f1frv@free.fr OR

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