David, try using one or two band pass only cavaties in
the receive side instead of the BpBr type. The BpBr
filters often do not discriminate against signals far
off the pass frequency, and you may not be getting
enough rejection out of your input cavities.
73 - Jim W5ZIT
--- David Epley <[EMAIL PROTECTED]> wrote:
> I have a repeater receiver overload problem I am
> trying to cure. The
> repeater is a 900mhz 927.7125/902.7125. There is an
> FM broadcast station 100
> yards away 104.9mhz. The repeater works fine at
> another site. My transmitter
> is a Motorola Purc 5000 running 75 watts the
> receiver is a converted maxtrac
> 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I
> have 10 to 12 db
> degradation when plugged into 3 different antennas
> on the tower. When I use
> a 900mhz dish antenna pointed away from broadcast
> tower I only have 3 db
> degradation. I have tried 3 different maxtrac
> receivers, added 2 more BpBr
> cavities in the receiver side and used 3 pole
> filters in the receivers with
> no improvement. Today I looked at the signal level
> getting to the receiver
> at 104.9. To my surprise I was getting -8 dbm at the
> receiver. I believe
> this level is overloading the front end of my
> repeater. I was wondering if a
> stub cut for the broadcast frequency would work. Any
> thoughts would be
> greatly appreciated.
>
>
>
>
>
> David Epley, N9CZV
>
> Winchester, Indiana
>
>
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