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Re: Spurs - BPF fix? #ubitx

 

Allison

Re.? the Elliptical filter...moved spur trap to 23.8.?

LTspice IV - Cauer_Elleptical_Filter_dip_at_23.8_MHz.asc_042.png

I moved the trap frequency to 23.8 by changing value of L3.? Then R2 was changed
from 3 ohms to 0.5 ohms to give more attenuation.? This might work if the trap is not
too narrow to cover possible spur frequency range.? Attenuation is now 45 DB.?

Arv
_._


On Tue, Aug 14, 2018 at 9:08 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
Arv,

Interesting filter.? However how effect is it? at 23.8mhz (dial frequency of 21.2)?
Looks to be maybe 18db loss at that frequency.? It may be enough.


Allison

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