Theory seldom, if ever, approaches practice <grin>.
de Paul, W8AEF
-----Original Message-----
From: Bill Turner
Sent: Friday, August 23, 2013 9:42 AM
To: RTTY Reflector
Subject: Re: [RTTY] 300hz or 500hz IF filter?
ORIGINAL MESSAGE: (may be snipped)
REPLY:
Jay has summed it up well. Practical, on the air testing is always the best.
Theory can point in the right direction and might save some time, but the
acid test is on the air.
For example, I operated RTTY for years with an IC-756Pro3 using a 250 Hz
filter and it was very satisfactory. About two years ago I upgraded to an
IC-7600 and set it to 250 Hz as well. I was quite disappointed in the copy.
Even on strong signals, there were many errors in the print. On a hunch, I
widened the filter out to 300 Hz and reception returned to satisfactory. The
difference was the '7600 had steeper skirts than the 'Pro3. The point is,
just stating an "optimum" filter bandwidth is too simplistic. It depends on
other variables.
Theory helps, but "cut and try" will give the final answer.
73, Bill W6WRT
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