[Amps] Input Matching for 8877 on 2m
David Smith
vk3hz at wia.org.au
Fri Dec 12 12:04:15 EST 2003
I'm building an 8877 amp for 2m - K1AGB grounded-grid stripline design - and
I'm having problems with the proposed input matching circuit (which is the
same as for the more popular W6PO design).
The original circuit uses a T type match with a blocking cap and variable
inductor with a "white slug" in series with the input, then a variable cap
to ground, then a fixed inductance to the cathode of the 8877. I can't find
a source for the variable inductor, so I wonder if anyone can suggest
alternatives?
For example, can I change the circuit values and use a variable cap in place
of the variable inductor? Can anyone point me to a suitable site with info
on calculating the values for such a matching circuit. According to the
article, the 8877 input is equivalent to 54 ohms in parallel with 26 pF.
Thanks,
David Smith
VK3HZ
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