[Hallicrafters] SX-100 Mark1 and Mark2 defferences

[Jim Liles]

Good morning Reymond:
Three of the major differences between the Mark1 and Mark2 are the IF is aligned at 50.75 instead of 50.kHz providing better sideband rejection and more importantly the BFO feedback effect on  AGC is reduced significantly (The BFO signal rolls backward through T5 and T6 to the AGC detector).  Also, added, is slow AGC for SSB.  Last, the BFO signal is tapped from the plate side of the BFO transformer rather than the grid.  Net result,  you can turn the RF gain to max for SSB and enjoy a significantly improver radio.  The Mark1 IF can simply be aligned to 50.75kHz, the AGC requires a switch and capacitor, and the BFO a wire move and capacitor.  Kindest regards Jim K9AXN