[CQ-Contest] W3NQN Bandpass Filters (Was: Re:419bandpassfilters..

[Jukka Klemola]

...
>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.
>
>73 de Mario, S56A, N1YU


I have a 4o4o4 on 10m, and a 4o4 on 15m on both towes, total 10 yagis
15+10m.
The closest spacing on both towers is maybe 2m or so.
That is 6 to 7 feet.

I think my antenna spacings are "maybe" too short.

In addition to ICE filters, I use stubs, K2TR design.
The stubs are made of 1/2" hardline.

I have no 15 to 10m nor 10 to 15m problems.
My improvement wish is to attenuate harmonic from 80CW to 40CW, 40 to 20
CW+SSB and 20 to 10 CW+SSB.
 
My thinking is these harmonics will not really help if I change to NQN
because the harmonics are created in the amps.

However, if I use only FT1000MP radios, the level of harmonics is bigger
than compared to harmonics using amps and all the filtering.

On 15/10m, if I remove the ICE filters using amps, the only phenomena I
get is wideband phase noise from band to band.
ICE filters attenuate enough so the phase noise goes below the noise
floor.
Of course the stubs effects on adjacent bands help a lot by K2TR design.

At least in my case ICE filters are good enough on those two bands.
Budget contesting is !


73,
Jukka OH6LI