[Boatanchors] COST of radio SX-25

[james.liles]

The SX-25 works well except for band 4.  It uses two RF amplifiers which actually degrade the radio.  Why?  Band 4 was added as an after thought and the tracking of the pre-selector circuits begin above and end below the local oscillator from one end of the band to the other.  Two RF amplifiers simply compound the problem with sensitivity.  I corrected my SX-25 band 4 by adding a half turn to each coil and a moveable shorted loop around each coil.  Enables tracking adjustments with a Grid Dipper which can be used on the band 4 coils.  There is no other solution except maybe the S-40 coils???  Haven't tried that though.  Lastly the warble on band 4 is the output of 6K8 LO/mixer tube doing some FM gyrations --- haven't looked at the reason yet --- looks like spread spectrum on a spec analyzer.  Good luck --- that radio is a great piece of history.  Kindest regards Jim K9AXN