All signals to some extent or another have noise in them. This is why instrumentation utilizes filters in order to block unwanted frequencies and such. Noise can interfere with sensative instrumentation that is working on a small scale voltage, etc. Utilizing an instrument like a multimeter will not show this situation.. you truly do need a signal analyzer which can capture and magnify the signal. You can then see if there is a fluctuation in the frequency as well as eronious noise in the main signal... think of a nice smooth oscillating line like you'd draw with a pencil... then redraw that line but instead of being smooth make the line very shaky and jagged as you retrace the original line. that'd be one example of noise...

i own a 5-0-5 and an RCBS digital. i use the digital more than the ole beam though... i find if i get close and trickle some in and give the pan a little nudge it'll upset the scale and instead of taking forever to update it'll pop to the actual measurement. I also tend to calibrate just to make sure it's thinking straight before i sit down to do any loading... if i am weighing every charge i'll often check to make sure the scale is staying zero'd. my RCBS tends to be a little finicky now and again... but for some reason i dont care to fiddle with the beam... the one thing that really bothers me when iam being ANAL is the 0.05 gr resolution of the digital... if you are .48 it is going to say .4 if you are .52 it's going to say .5... kinda silly to worry about now that i think of it... but with the beam you still have to eyeball it and wait for the oscillations to settle and hope there isn't any significant friction to stop the beam from moving when it is just creeping home...

the greatest asset to my reloading venture has been an RCBS hand primer... a good cheap progressive loading press like the Lee turret is nice to just throw together plinking loads for the revolver too...

Jamie