[VHFcontesting] Doorknob Capacitor Resonances

[Jim Worsham]

Hard to confirm without the actual device in hand but I will say that I wouldn’t be surprised.  You need to take the individual Cs out of the circuit and sweep them to see where they series self resonate (their impedance will be very low).

73
Jim, W4KXY

Sent from Mail for Windows 10

From: Steve Kavanagh via VHFcontesting
Sent: Friday, November 10, 2017 12:18 PM
To: vhfcontesting at contesting.com
Subject: [VHFcontesting] Doorknob Capacitor Resonances

I'm evaluating a low pass filter (for 6m) I acquired recently, which does a dandy job up to 250 MHz or so, but it has a few spurious responses between 300 and 500 MHz.  It behaves like the 50 pF/7.5 kV and 100 pF/5 kV doorknob capacitors it uses must be self-resonant in this range.  Can anyone confirm this?

73,
Steve VE3SMA
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