> As far as I can tell the only advantage to pure FSK is that some
> radios have pre programmed narrow RTTY filters inside the AGC loop
> may not let you program the radio's SBB filters to keep strong
> adjacent stations from killing the RF gain.
The narrow IF filters are a significant advantage, not only for the
AGC protection but in preventing IMD generation.
> Otherwise the DSP audio filtering in a program like MMTTY is far
> superior than any radio's IF filters.
No audio DSP can prevent the AGC and IMD problems. By the time the
detected audio reaches the software, the damage has been done.
However, there is a whole list of potential problems on the transmit
side with improperly generated AFSK ... including distortion in the
mic input, hum, clipping/clicks if the SSB compressor is engaged, and
external (SSB) audio from open mics and/or other programs accessing
the soundcard.
Those who promote AFSK, particularly with transceivers that have a
dedicated FSK mode and lack the ability to mute the microphone in
"digital mode" operation, do a disservice to both the customer and
amateur operation in general a disservice.
73,
... Joe, W4TV
On 4/30/2010 11:33 AM, Marty W8AKS wrote:
> I took the liberty of forwarding Don's message on to Del at West Mountain and
> here is his answer,
> 73
> Marty
> W8AKS
>
> ----- Original Message -----
> From: Del Schier
> To: rigblaster@yahoogroups.com
> Sent: Friday, April 30, 2010 15:02
> Subject: RE: [rigblaster] Fw: [RTTY] Rigblaster Plug& Play Question
>
>
>
> Yes the RIGblaster P&P optoisolated CW keying output could be controlled by
> the MMTTY EXTFSK extension. If it is set to key DTR it would work.
>
> You would just have to make the appropriate cable and set the xmit shift
> right. You might even be able to parallel the RIGblaster keying output to
> key both a CW straight key jack and the FSK keying inputs, switching modes
> with the radio mode switch.
>
> Note that AFSK works very well with the advantage that the software AFC
> tunes automatically and precisely zero beats the other station; a slow and
> tedious manual operation with true FSK. As far as I can tell the only
> advantage to pure FSK is that some radios have pre programmed narrow RTTY
> filters inside the AGC loop may not let you program the radio's SBB filters
> to keep strong adjacent stations from killing the RF gain. Otherwise the
> DSP audio filtering in a program like MMTTY is far superior than any radio's
> IF filters.
>
> Thanks,
> 73
>
> Del Schier, K1UHF
>
> West Mountain Radio
> 34 Smith Street
> Norwalk, CT 06851
>
> <http://www.westmountainradio.com> http://www.westmountainradio.com
> tel: 203 853 8080
> fax: 203 299 0232
>
> From: rigblaster@yahoogroups.com [mailto:rigblaster@yahoogroups.com] On
> Behalf Of Marty W8AKS
> Sent: Friday, April 30, 2010 8:51 AM
> To: rigblaster@yahoogroups.com
> Subject: [rigblaster] Fw: [RTTY] Rigblaster Plug& Play Question
>
> Del, I found this in my email this morning. Do you have any comments? I can
> repost them on the rtty reflector if you would like.
> 73
> Marty
> W8AKS
>
> ----- Original Message -----
> From: "Don Hill AA5AU"<aa5au@bellsouth.net<mailto:aa5au%40bellsouth.net> >
> To: "'RTTY Reflector'"<rtty@contesting.com<mailto:rtty%40contesting.com> >
> Sent: Friday, April 30, 2010 3:35
> Subject: [RTTY] Rigblaster Plug& Play Question
>
>> Updating some of my web pages and reviewing the Rigblaster Plug& Play
>> unit information I have on hand. I know from past reviews of
>> this unit that it is not intended for FSK transmission. However, since it
>> does CW keying using the DTR line of the built-in
>> USB-to-serial converter, is there any reason why this CW line couldn't be
>> used for FSK with MMTTY with the use of EXTFSK. If FSK is
>> configured to DTR in EXTFSK, it would seem that you could then key FSK
>> instead of CW using the CW line of the Rigblaster Plug&
>> Play. I see no reason why it wouldn't work. Doesn't anyone else?
>>
>> Has anyone tried this?
>>
>> 73, Don AA5AU
>> http://www.aa5au.com
>> http://www.rttycontesting.com
>>
>> _______________________________________________
>> RTTY mailing list
>> RTTY@contesting.com<mailto:RTTY%40contesting.com>
>> http://lists.contesting.com/mailman/listinfo/rtty
>
> [Non-text portions of this message have been removed]
>
>
>
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