[amsat-bb] Re: D-STAR repeater problems in Copenhagen

[G0MRF@aol.com]

Hello Ib.
 
Interesting allocation for D-Star.
 
-60dB at 145.800 may sound suitable, but in practice what matters  is how 
many dB down it is at 145.800 minus one half of the bandwidth of  your IF filter.
 
Ball park.........
So -4kHz of doppler and -7.5kHz for a narrow FM filter gives your receivers  
bandpass down to 145.7885 MHz just 10k above the D-Star
 
Which means the two are probably going to overlap.
 
73
 
David
 
 
 
 
In a message dated 07/12/2008 20:34:56 GMT Standard Time, oz1my at privat.dk  
writes:


The  theoretic spectrum should be more than 60 dB down
on 145.800 MHz,but that  does not seem to be the case.
Including doppler the downlink from ISS is  145.796 MHz, when 
it is going away from us to the East, which is the  direction
of the repeater :-(

Personally I am just 6 km away from  the repeater with 
no obstructions on the pass from  it.