[AMRadio] Trapezoidal pattern scopes

John Lawson jpl15 at panix.com
Wed Dec 27 12:54:15 EST 2006

On Wed, 27 Dec 2006, D. Chester wrote:

> One problem with monitoring the trapezoid pattern all the time is that it 
> will burn a dark vertical line onto the face of the scope tube, where the 
> unmodulated carrier appears.

   Quite likely, on an old, cheap scope with a crappy CRT.

   And cheap scopes are available everywhere - folks at swapmeets throw 'em 
away at the end of the meet...  so you can easily have a few of the older 
Eico, Heath, RCA, etc. lying about waiting to be pressed into Monitoring 

   Also, the Resourceful AM Ham could easily make a little diode 
detector/amplifier type thingy and use it to blank the Z-axis (or dim it 
substantially) during periods of no mod.

   I have done the above - and I also snagged a Central Electronics MM-1 
scope, which, when it's HV issues are sorted out, will be used here at the 



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