HI,
the 250 Hz is the best ! (for RTTY, of course)
73, Frantisek, OK1DF, ex 7X0RY
---------- Původní zpráva ----------
Od: Joe Subich, W4TV <lists@subich.com>
Datum: 27. 11. 2013
Předmět: Re: [RTTY] What are the best K3 filters for digital use?
"> I am concerned that the 200 hz might be too narrow for RTTY.
The 200 Hz filter is too narrow (mine measure about 190 Hz at -6dB).
The "250 Hz" filter - nominally 370 Hz at -6dB - is a good match to
the minimum necessary bandwidth for MMTTY, 2-Tone, etc. to function
well (particularly if the DSP bandwidth is set for 400 Hz).
I generally use the 400 Hz filter (435 Hz @ -6dB nominal) with good
results. If I had the 250 Hz filter I would pair it with the INRAD
500 Hz filter as the difference between the 400 (435 Hz) and 250 (370
Hz) are not enough to be significant. The 500 Hz and 250 Hz filters
also make good "narrow filter" for PSK31 or JT65/JT9 if necessary to
get rid of strong interfering signals on the "other end" of the
passband.
73,
... Joe, W4TV
On 11/27/2013 11:01 AM, Dave Barr wrote:
> Which two of the 200/250/400 and 500 filters are best for digital use,
> primarily RTTY contests and dx. I understand that for JT-65 and PSK the
> standard ssb filter, or even an AM filter is useable. I am concerned
> that the 200 hz might be too narrow for RTTY. I look forward to any
> advice given.
>
> 73, Dave, K2YG
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> RTTY@contesting.com
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>
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