lambdaanttech
Newbie level 6
Hi all ,
I'm looking for the design formulas for a cavity filter .
I want to build a cavity filter for 408MHz for radio astronomy purpose .
The idea is to place an adjustable tube inside another tube and working with coupling loops to form a cavity filter, just like the ordinary quarter wave cavity filters .
I have found a lot of information (pictures) on the net but haven't found the formulas how to calculate the resonance frequency , dimensions of the coupling loops , tube diameters etc ...
Anyone can advise me some links , formulas or a good book ?
I'm looking for the design formulas for a cavity filter .
I want to build a cavity filter for 408MHz for radio astronomy purpose .
The idea is to place an adjustable tube inside another tube and working with coupling loops to form a cavity filter, just like the ordinary quarter wave cavity filters .
I have found a lot of information (pictures) on the net but haven't found the formulas how to calculate the resonance frequency , dimensions of the coupling loops , tube diameters etc ...
Anyone can advise me some links , formulas or a good book ?
