[RTTY] any way

Joe Subich, W4TV lists at subich.com
Sun Jul 19 13:37:34 EDT 2015


 > DONT LIKE SOUND CARD NO FILTERS. OR IS THERE SOME FILTTERS YOU
 > CAN BULDING -TO RUN OUT OF REC. TO SOUND CARD..

You don't need filters with sound card RTTY as long as you turn
off the receiver AGC and adjust the RF Gain to prevent strong
adjacent signals from overloading the receiver and/or sound card.

A decent sound card has a dynamic range of around 90 dB - which
means signals up to S9+20 dB should be fine if the receiver can
handle them.  The attenuator in the typical receiver should be
good for another 10 dB if needed before resorting to the RF (or
IF) gain control.

This doesn't mean that a quality 400 or 500 Hz (CW filter) will
not help sound card RTTY with most rigs - it will certainly mean
less need to adjust the attenuator or RF/IF gain.  However, the
sound card RTTY software (MMTTY, 2Tone, etc.) does the MARK/SPACE
filtering in the digital domain which means the IF filter primarily
protects the IF, product detector and AGC system against overload
from strong adjacent signals.

73,

    ... Joe, W4TV


On 2015-07-19 12:38 PM, wa4jjy at comcast.net wrote:
> WAS ON RTTY WAY BACK IN 64.HAVE BEEN OF AND ON BUT DONT LIKE SOUND CARD NO FILTERS.
> OR IS THERE SOME FILTTERS YOU CAN BULDING -TO RUN OUT OF REC. TO SOUND CARD..
>
> IS THERE ANY WAY TO RUN ANY OF THE OLD TU -LIKE HAL ST-6-----PK232--- 2232 ON SOUNDCARD..
> TNX
> EDDIE
> WA4JJY
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