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"Have you ever noticed" (Now I sound like Andy Rooney) how different =
the plate load impedance/component value charts (C1, C2 L1 L2) for a =
given plate load change markedly between different publications ?
I have noticed in the 23 edition of the "Radio Handbook" the chart for =
the Pi-L network has values for the Q of 10. In the 1998 "ARRL Handbook" =
the chart for the same plate load impedance has about the same values =
(within 5 % ) and that chart is for a Q of 12. I have also noticed that =
different publications give the formula for calculating the palate load =
impedance different as well. Some books give a "K" value of 1.8 (23rd =
radio handbook), and the some give the "K" value of 1.57 ???
In the information sheet that I have from Eimac on the 3CX800A7, this =
sheet says that the plate load impedance value for the tube operating at =
2200 VDC and a plate current of .5 amp is 2700 Ohms. This makes the "K" =
value 1.56.=20
All of the values for "K" are for the tube operating in class AB2......
On another note, I also have observed that the overall efficiency and =
low quantities of heat, and the reliability of the tank components of =
H.F. amplifiers that have a relative low value of plate load impedance =
(1500-2000 Ohms) seem to be more efficient and run much cooler than the =
high plate load ( 3500-4000 Ohms) amplifiers.=20
I would like to hear what Rich, Dick Erhorn (sp. ?) and Carl have to =
say about the conflicting information.............
Just curious and its time for a "new" discussion here on the amps =
reflector........
73 and thanks
Jim W7RY
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<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>"Have you ever =
noticed" (Now I=20
sound like Andy Rooney) how different the plate load =
impedance/component=20
value charts (C1, C2 L1 L2) for </FONT><FONT color=3D#000000 size=3D2>a =
given plate=20
load change markedly between different publications ?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>I have noticed in the 23 edition of =
the=20
"Radio Handbook" the chart for the Pi-L network has values for =
the Q=20
of 10. In the 1998 "ARRL Handbook" the chart for the same =
plate load=20
impedance has about the same values (within 5 % ) and that chart is for =
a Q of=20
12. I have also noticed that different publications give the =
formula for=20
calculating the palate load impedance different as well. Some books give =
a=20
"K" value of 1.8 (23rd radio handbook), and the some give the=20
"K" value of 1.57 ???</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>In the information sheet that I have =
from Eimac=20
on the 3CX800A7, this sheet says that the plate load impedance =
value for=20
the tube operating at 2200 VDC and a plate current of .5 amp is 2700 =
Ohms. This=20
makes the "K" value 1.56. </FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>All of the values for "K" =
are for the=20
tube operating in class AB2......</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>On another note, I also have observed that the =
overall=20
efficiency and low quantities of heat, and the reliability of the tank=20
components of H.F. amplifiers that have a relative low value of plate =
load=20
impedance (1500-2000 Ohms) seem to be more efficient and run much cooler =
than=20
the high plate load ( 3500-4000 Ohms) amplifiers. </FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>I would like to hear what Rich, Dick =
Erhorn (sp.=20
?) and Carl have to say about the conflicting=20
information.............</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Just curious and its time for a=20
"new" discussion here on the amps =
reflector........</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>73 and thanks</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Jim W7RY</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV></BODY></HTML>
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