Topband: W8ji ATR-10 design 160M?

[Paul Christensen]

> So what different bout your tuner, is it like the ATR-10 design?

Nothing special.  It's just a symmetrical balanced tuner with a pair of 
synchronized roller inductors and a large vacuum variable cap (with a very 
small minimum C and large max C) that's switched with a pair of vacuum 
relays.  A 1:1 coaxial choke is used on the input since the circuit is 
symmetrical.  In fact, it's really just a variation of the AG6K tuner 
described in QST some twenty years ago.

I went with this design since I'm presently restricted to wire antennas. 
And due to the presence of switch-mode appliance noise, the goal was to keep 
the open feeders as far away from the house as possible.  Balanced open 
lines are capable of a high degree of balance but on receive, their ability 
to cancel noise is dependent on the orientation of the line to the direction 
of the noise source.  If you look at early literature from the 1930s, open 
feeders often used transposition blocks.  I own several different types made 
by E.F. Johsnon as display pieces.  Nice concept -- I'm not sure how 
satisfied I would be with using them.  Anyway, to better deal with the 
household noise issues, the tuner is located outside of the house, in a 
weatherproof enclosure.  LMR400 is then used between the tuner and shack.

Paul, W9AC