[AMPS] "Experts" Resistance to Resistance

[Rich Measures]

*Proceedings of the Institute of Radio Engineers*, 
September, 1935.  


"PARASITES AND INSTABILITY IN RADIO TRANSMITTERS"  
by G. W. FYLER, General Electric Company, Schenectady, New York.  

	" ...  Methods of locating and eliminating parasitic circuits are 
discussed.


"A PARASITIC in radio work is any spurious oscillation taking place in a 
vacuum tube circuit other than the norrnal oscillation for which the 
circuit is designed. ... ... "
... ... ... 
-  "Conclusions:
  In the elimination of parasites from a transmitter, the circuits should 
be kept as simple as possible to prevent complex resonance conditions.  
Radio !requency choke coils and shunt-feed circuits should be kept at a 
minimum.  Wide band neutralization circuits are desirable. The grids of 
vacuum tubes should be effectively by-passed capacitively to the cathode 
through a capacity and inductance added next to the plates of the tubes 
to eliminate shortwave (VHF) parasites. If necessary, the plate or grid 
parasitic circuits should be damped with resistance. ... ... "
--------
In the 1926 and 1927 Radio Amateurs Handbook, F. E. Handy recommended the 
use of resistance wire to reduce parasitic oscillations.  In Oct., 1988, 
an article about the use of resistance wire to reduce parasites apeared 
in *QST*.  In 1996, tests were performed with a HP Z analyzer which 
indicated that, all other things being equal, VHF suppressors made from 
resistance wire provide an improvement of roughly 40% compared to 
copper-wire suppressors. 

 .  Where's the beef? 


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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