Re: Power output on 20 meters.
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John? VA7JBE
I might suggest using LTSpice to play with adding parallel caps and with adding series traps.?
This lets you juggle component values to match particular needs, and to see the probable
attenuation these changes might provide.
Arv? K7HKL
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On Fri, Aug 17, 2018 at 12:58 PM John VA7JBE via Groups.Io <va7jbe= [email protected]> wrote: I have a QCX20 in the mail and I'm wondering if it might be worth replacing the LPF with one of the 'new' (1999) CWAZ filters presented by Ed W3NQN in QEX, .? Based on the simulations in the article, adding a capacitor in parallel with the middle inductor to create a tuned circuit increases attenuation at the 2nd harmonic and also reduces return loss in the 20m band (Figures 2 and 3.)? Has anybody tried playing with these filter designs before?? Also, which capacitors should I use?? The article recommends the Philips 680 line of ceramic capacitors but I've been having a hard time finding them.? Would any 100V, NP0/C0G ceramic capacitor of reasonable tolerance do?
Cheers,
John VA7JBE
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