Ceramic filter

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radium98
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Ceramic filter

Post by radium98 » Thu Sep 14, 2017 9:00 pm

Do it possible for any expert to give me the right bandwith of thoses two ceramics filters 10.7 mhz .
And what about if i put them all the same eg only with center frequency
And what if i remove them .
L have attached some pictures
Regards.
photo 1-12.JPG
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Analyser
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Re: Ceramic filter

Post by Analyser » Fri Sep 15, 2017 7:27 am


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Re: Ceramic filter

Post by sinus trouble » Fri Sep 15, 2017 11:27 pm

Hello Mr Radium :)
You may already know this? Not all, but most receivers use 10.7mhz difference between the local oscillator and the received signal for demodulation! Eg if you want to receive 50mhz? your local oscillator might run at 60.7mhz! The purpose of the ceramic filter is to suppress all other unwanted mixed harmonics and boost the 10.7mhz that you want! If you remove the filters, spurious crap will cause problems!
Heres a vid to show mixing principles!

I am as stupid as I look! :|

radium98
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Re: Ceramic filter

Post by radium98 » Sun Sep 17, 2017 8:07 pm

thank you both of you m8 for the very good explanations but i am still eronic :( i cannot lead to read the correct bandwidth of those two ceramic filters up :( oi need there bandwidth as on the schematic they said to use 10.7 mhz bandwidth respectively 280 and 180 khz if possible lead me to correct values if no can i use them in this case ?
pdf picture schematic inside rar file
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Re: Ceramic filter

Post by Analyser » Sun Sep 17, 2017 10:30 pm

Can't open the rar file.

radium98
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Re: Ceramic filter

Post by radium98 » Mon Sep 18, 2017 5:40 am

https://www.sendspace.com/file/ajatgv

starnge Analyser it work to me i mirrored to sendspace it is a pdf extension and forum do not allow pdf extension thanks for looking to try solving my problem

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Re: Ceramic filter

Post by Analyser » Mon Sep 18, 2017 4:47 pm

Ok, so the big (wider) filter marked T10.7S is a Murata SFT10.7MS3-A, and it has a 180KHz bandwidth.

The other smaller filter marked L10.7A is a generic 280kHz filter, equivalent to Murata SFE10.7MA5-A.

radium98
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Re: Ceramic filter

Post by radium98 » Mon Sep 18, 2017 6:37 pm

Thank YOU Analyser .HUG

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