[Kenwood] SM-220

[Rob]

What is the range of frequencies displayed by the 220 panadapter?  Is  
it dependent on the width of the 8 MHz IF filter?   To me it seems  
that would make it so narrow as to not be very useful.


> Personality, the SM-220 is getting to be
> less of a value to have in the long run. Visual transmitter monitors  
> are
> easily attainable using an off-the-shelf type flea market scope and a
> simple RF pickup.


I made an inline RF voltage pickup by taking one of those cheap CB swr  
meters and drilling a hole in the cabinet and adding a BNC jack, and  
running a wire from the jack's center to the pot that adjusts the  
forward set level for the meter.  Since the meter needs a diode to  
power it off of picked up RF, a tap off the pot that varies this  
source to the meter gives a variable level to the BNC jack so the  
scope has a signal from the exciter for that part of the trapezoid  
display, for making sure the amp is linear.   Cheap five buck flea  
market swr meter--millions of them were made for Midland, Lafayette,  
Allied...the older ones in steel cabinets were pretty well made.  the  
pickup on the high power side of the amp can be as little as a coil  
wrapped around the feedline....

73

rob / k5uj