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Re: How to find the missing "Low pass filter at 30 MHz" article by W7ZOI #ubitx

 

Jerry and? Andy
the filter implemented by Andy looks performing nice.? Can als o try similar with the design of Eamon Skelton EI9GQ please.
?HE GAVE A GOOD GRAPH OF HIS? ROOFING FILTER.. One of my acquaintances vu3iia tried it with good results.
HEREIS THE LINK

?Regards
?sarma
vu3zmv

regards
Sarma
?

On Sun, Dec 31, 2017 at 8:13 AM, AndyH <ahecker@...> wrote:
I don't know what specific parts W7ZOI used.? There's very little power flowing through this filter, though, so it should be easy duty for the components.

I used these:



And the filter seems to work pretty well.



(ignore the trace prior to about 3.5KHz - that's below the range the Sweeperino can signal)
73
Andy, KG5RKP

On Thu, Dec 28, 2017 at 09:51 am, ohwenzelph wrote:
any one know the characteristics of the surface mount he ended up using? and could you transmit at uBitx powers thru that filter?
are there toroids that could be used instead, perhaps with shielding between sections? the standard values for 9 and 10 turns on the ones he used are not that close to what he was looking for.
jerry aa1of
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