[AMRadio] need help


esieb at sympatico.ca esieb at sympatico.ca
Wed Oct 19 11:45:50 EDT 2005


I'd have used an MFJ 259B to actually measure the input Z.  Alternatively, 
you  can always use a  small tuner to "tune" the input.  I do that anyway 
with my Drake L4B, (use a small MFJ mobile tuner with meter).

4-400's, eh?  Nice amp!  If your plate voltage is high enough, you ought to 
get serious power out of that baby!

73, Ed, VA3ES


From: Edward B Richards <zuu6k at juno.com>:

I want to drive a linear amplifier with a rice box that requires a 50 ohm 
load.
The linear amp uses an input to a 170 ohm, 80 watt swamping resistor to 
ground, then
through a .001 mfd capacitor, then through a VHF parasitic suppressor
consisting of  4 turns of wire around a 47 ohm resistor, to the grids of
a pair of parallel connected 4-400A tubes.

What I need to know is the impedance of the input. Is it close to 50 ohms
or do I need to use a matching network between the rice box and the
linear amplifier.





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