ANTENTOP- 01- 2017 # 021

Simple ATU

Simple ATU

Credit Line: Forum CQHAM.RU

Note from I.G.: I found schematic of the tuner on infinite pages at the ham forum at www.cqham.ru. The design was present by amateur with alliance Svoy- 3000. Of course I have decided make and test the ATU. It was not the same ATU that shown in the schematic because for inductors I used plastic cans from Drug Store that had a little different diameter and L1 and L4 were wounded directly above L2 and L4.

My test showed that the tuner worked very well! I recommend use L5 with short antennas on 160 and 80 meters- matching much better then without this one.

(Svoy does not use L5 in his practical design).

Svoy - 3000

It is very simple tuner that without complicated switching could work at all amateur HF Band- from 160- to 10 meters. I tested this tuner with my ICOM- 718 with horizontal low height wires antenna in 5 and 10 meter length (it was used a counterpoise in 10 meters length) feeding by 5 meter length of coaxial cable and with different resistive loads.

I did not measured efficiency of the tuner by measuring means. However I measured field strength by MFJ FSM MFJ- 801. I measured field strength from antennas matching by the home made tuner and matching by the MFJ- 941 VERSA TUNER. It was occurred that the tuner worked almost similar to MFJ- 941 VERSA TUNER. I used usual air capacitors from an old tube receiver. Those ones began arced already at 50- Wt power in. So for high power it needs to use capacitors with big gap between plates.

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