Yet more Cavity filter measurements

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Len Spyker
Posts: 147
Joined: Sat Apr 28, 2018 6:48 pm

Yet more Cavity filter measurements

Post by Len Spyker » Sun Sep 07, 2008 11:58 am
















Hi guys

Today I built up my coax s/n 008 out of  experimental
bits and scraps.

A  hybrid between the original and the coax kits I made.

The hairpins were tucked under the coax tube bases (not into
the bottom plate) and tacked in place with silver solder.

The inner coax tubes were pretty bashed around and not smooth
at all.

The Base and Top were baked on the gas stove with solder
paste. Results:

Loss @ 1013  -6db 

-3db       2.6 MHz wide   

-60db    11 MHz wide

-90db    25 MHz wide

Note: The hair pin spacing to the wall  is
super critical and the inner post lengths are critical too.

Even tough some small amount of solder
leaks into the base of the coax tube (around the tube edges) with the solder paste
bake process  it does not seem to hurt.

 

My 2 year old coax #2 done as per original process and tested
independently by Rex Pearson in Queensland (a state in Australia)

Many thanks to you Rex.

Insertion
loss:               
4.23dB

+3dB
up                       
1014.18Mhz

-3dB
down                    
1010.76Mhz

 3dB bandwidth 3.42Mhz  Return loss ~ 9.5dB

 

+30dB
up                     
1016.42Mhz

-30dB
down                  
1008.66Mhz

-30dB bandwidth 7.76Mhz

 

+60dB
up                     
1024.6Mhz

-60dB down                  
1003.56Mhz

-60dB bandwidth 21.04Mhz

 

Len Spyker

 






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