The theoretical bandwidth of 170 Hz shift 45.45 baud RTTY is just under 250 Hz.
73
Kai, KE4PT
On 8/22/2013 6:54 PM, Joe Subich, W4TV wrote:
The -6 dB bandwidth of the INRAD "300 Hz" filter is shown as 340 Hz
which is slightly less than the theoretical 370 Hz required for 170 Hz
shift 45.45 baud RTTY.
That said, performance will be a trade off between improved
selectivity and interference rejection - up to a point. If the
receiver can withstand AGC effects of close in interference, a 400
to 500 Hz filter will generally provide better copy than a 300 Hz
filter. Note: no amount of selectivity is useful when signals
overlap or the interfering signal includes distortion (spurious)
products that overlap the desired signal.
73,
... Joe, W4TV
On 8/22/2013 5:38 PM, David VE3VID wrote:
Hello everyoneI would like to outfit my FT-857D portable rig with an IF
filter on its 455khz stage. INRAD sells a suitable 500hz unit. They also
have a 300hz unit. I am leery about the 300hz filter being too narrow.
Any opinions?
73Davidhttp://www.ve3vid.webs.com/
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