[ARC5] "Bandspreaded" R25/ARC-5

[J Mcvey]

This R-25 had a 3/4 completed "ham-ering"  that piqued my curiousity. I reversed all of the mods EXCEPT the tuning gangs which had all but three rotor blades removed in each section. The original setup used 75 pf in each section to compensate for the missing blades. Even with the trimmers unmeshed, the max frequency was 1.9 MHZ.Changing the compensation caps to 50 pf micas allowed tuning  from 1.7MHZ to 2.05 MHZ with approx 50% trimmer mesh.
I thought that  I was going to hate this mod, but I have changed my mind. It actually was joy to use on 160 meters. The wide spread and vernier action makes tuning very easy, In fact , dialing in SSB was quite easy as opposed to the usual "fine touch" it requires on a normal ARC set. CW was very easy.Sensitivity was excellent as the bench test had indicated.


Other items to be addressed:Takes a long time to stop slowly drifting downward 
Need to find a dial with bad paint or badly scratched to make a calibrated dial. This one is too good to repaint.IFs are very broad.Thought the ARC's had an AGC, but loud stations  overload the radio. It's annoying when a close station is talking to a distant one.

 
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