[OFARC] Club Band pass filter project

[rusty-wilson at comcast.net]

I have managed to rescue 3 (so far) dead power supplies from recycle at the office. 

I might be able to round up a few more :) 

Rusty 



----- Original Message -----

From: "KG5IRR via OFARC" <ofarc at mailman.qth.net> 
To: "Ralph" <ke5hdf at sbcglobal.net>, "OFARC" <ofarc at mailman.qth.net> 
Sent: Saturday, September 2, 2017 9:17:09 AM 
Subject: Re: [OFARC] Club Band pass filter project 



Ralph, 

I’m checking with some friends that still work at HP. This kind of stuff gets thrown out on recycling pallets all the time. I suspect they won’t be returning to work for at least another week. Ground floor of the buildings are under water. 

-Barry 




From: ofarc-bounces at mailman.qth.net [mailto:ofarc-bounces at mailman.qth.net] On Behalf Of Ralph 
Sent: Friday, September 01, 2017 5:12 PM 
To: OFARC 
Subject: Re: [OFARC] Club Band pass filter project 




i have been unable to find junked computer power supplies 

does anyone ave a computer repair shop they can check? 

or another source of boxes?? 



KE5HDF 

Ralph 




On 08/01/2017 09:16 PM, Ralph wrote: 




a while back, the club built some band pass filters. 

With all the new members plus increased interest in projects, I have received comments about doing it again. 

a band pass filter will allow signals of only the selected band to bass through. All others are blocked. 

This is very useful when there is severe interference from some source or there are multiple radios working close together (like field day or other joint event) 



The only parts are some wore coils wound on PVC pipe and some capacitors, plus the coax connectors 

We assemble them in the metal case from computer power supplies. (photo attached) 

We have plans and part numbers for 10M, 15M, 20M, 40M, 80M 

plus plans and component values for other bands. 



My thought is we work together to 

understand the filter & demonstrate winding the coils one month 

everyone winds their coils and mounts them at home 

demonstrate mounting the capacitors one month 

everyone works at home to mount capacitors 

the next club meeting we test the filters 

( OPEN FOR CHANGE/COMMENT ... just no rock throwing please!! ) 



Please let me know 

are you interested in doing this project 

the band you want most 

a secondary band you would like 

I will then confirm the part numbers and cost for each filter (guessing about $40) 



73 

KE5HDF 

Ralph 





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