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Ameco AC-1 problem
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March 14th 04, 06:54 AM
Uwe
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in article
, N2EY at
PAMNO wrote on 3/13/04 15:42:
In article , Uwe
writes:
When I increase the plate voltage to 325V my 2. grid runs about 280V and the
plate current increases to about 65 mA. I don't really dare to do that
without knowing the max values on that tube.
I guess I could lower the 2. grid voltage by increasing the value of the
resistor connectd to it.
I don't know if that would lower my plate current to what you get.
Uwe,
How are you tuning up the transmitter? Are you adjusting the plate capacitor
for minimum current?
73 de Jim, N2EY
Jim,
Sofar I have connected a scope to the antenna and tuned for max waveform eg.
highest voltage. That is also the setting where my dummy load with bulbs is
brightest.
The original instructions for the AC1 explain how to tune but use
expressions like 'turn the capacitor clockwise' which is useless to me when
I am not using their exact part.
They have an alternative way to tune by inserting a mA meter into the key
lead but I do not get the little dips in current they are describing. For me
it is more of a linear increase in current from the highest capacity setting
(lowest current) to the setting where the cap is all open and the current is
highest.
The way things are the max output occurs more or less at the lowest anode
current of my power supply (about 35mA at 200V B+).
Why do I tune for minimum current??
73 Uwe KB1JOW
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