Try a 3/4 wavelength stripline. Get the design info from W6GGV's
articles published in the Nov. '80, and Jan. through April '81
issues of Ham Radio.
Steve, K0XP
On 1/5/2024 12:28 PM, Jim VE7RF wrote:
YC-156 is good up to 150 mhz.? ? It will be used on 144 mhz.?
?
Yes, the 8877 has a 38.5 pf? between cathode and grid....and is
good up to 250 mhz.??
?
Question is.... how the hell do u make a tuned input for 144
mhz, with a whopping 92.5 pf of input C ??
?
With a conventional Pi tuned input....and an overall network Q
of '4'? ?( input Q = 2.2)? ( output Q = 1.8)
It's then? C1 = 49.1 pf? ?L= .04 uh? ? C2 =? 56.1 pf?
The input C is WAY more than the? required C2 value.? ?Note
this is based on a 35 ohm input Z.?
......................................................................................................................................................................................................................................................................................................................................................................................
?
OK, here's what might work....increase the overall network Q to
'8'? ? ( input Q =4.4)? ?( output Q = 3.6)?
It's then C1 = 96.8 pf? ?L =? .02 uh? ?C2 = 114.4 pf? ? Note,
this is based on a 35 ohm input Z.??
trying to fabricate a .02 uh inductor will be a trick. A
straight piece of copper strap might just? work.?
?
Jim? ?VE7RF
--
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