[Lowfer] Interesting nite...

[Michael Sapp]

John & Eric & All: Interesting capture extremes for me last nite....

      2014-07-11 04:44   WG2XIQ   0.475622   -33   0   EM12mp   1   WA3TTS   EN90xn   1743   55 


      2014-07-11 09:40   WG2XIQ   0.475620   -11   0   EM12mp   1   WA3TTS   EN90xn   1743   55  



The -33 catpure occured several minutes after having placed an extra 100uF cap across the output of a 
small 3A Rad Shack linear supply I was using to power the FT-817 IF receiver.  Just on a whim I had placed my Tek
O-scope across the 13.8 terminals of the supply and had noticed I had about 5mv PP of FT-817 audio
coming back through a LM317 set to 9.9V and 1mh + 100uf line filter between the FT-817 and B+ regulator. Yet,
this 5mv PP audio was present at the supply terminals. Not sure if the extra cap helped or not, as it did not quench the 5mv PP audio at the supply terminals....

I did try the multi-cap-shunt-resonance-killer thing and quickly found out not to bypass a 100uf cap with a .001 or .047
as all that did was raise the high frequency response noise level--substantially so.....best to stick with 1uf or 
higher I suppose...which lead me to read Application Note 1325 from Intersil on capacitor bypassing.....

So many "little things" make a difference at these frequencies.....73, Mike wa3tts