[CQ-Contest] W3NQN Bandpass Filters (Was: Re: 419bandpassfilters..
Marijan Miletic', S56A
s56a at bit.si
Sun Apr 1 12:47:03 EDT 2007
W0UN: The Dunestar filters are NOT 7-pole but rather 3-pole designs.
John, thanks for pointing my error! I am surprised with Dunestar modesty as they can claim 4 poles thanks to series resonances of losely taped inductor and capacitor combination. Applying the same rule to W3NQN, much better 8 poles might be considered at the cost of two additional serial inductors. I preffer to transfer RF energy at high voltage with a single capacitor.
Jukka, 10 m ICE BPF has only 16 db attenuation on 15 m. Even worse is only 11 dB attenuation of 15 m ICE BPF of 10 m signals. Your antennas are obviously spaced enough.
Another numerical mistake I made in my last post was on DL2NBU RX filters operating at 50/9 = 5,5 Ohms.
It was nice weekend with 9A hamfest and my tech presentation.
73 de Mario, S56A, N1YU
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