It's easy, a ELECTRICAL quarter wave length open stub or Half wave
shorted stub will give you a DEEP notch on the order of 25 to 32 db.
The electrical length is the mechanical length multiplied by the prop
factor. It's easiest done by cutting a bit long and pruning to length
using test gear to get the notch where you want it.
Good luck!
73
AC0Y
--- In Repeater-Builder@yahoogroups.com, "steve" <[EMAIL PROTECTED]>
wrote:
> Hi
> is there a fr,ee computer prog to work ot the lenghts of coax to
make notch filters ?. Iam starting to put together a 6mtr repeater
here in the UK, and need to play with coax to make a duplexer, can't
afford the prices of a ready made one.
> I don't fancy using heliax, OK it works, but looks a mess and takes
up so much space. So any ideas appreciated.
>
>
> 73
>
>
> Steve
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