RES: RTTY Filter for K3 PY5EG

[py5eg]

Hi Frank:
I didn't receive yet my optional filters, but I wondering what is the
software you are using in conjunction with the K3.
I'm using the Mixw2
Best regards
Oms PY5EG

-----Mensagem original-----
De: [hidden email]
[mailto:[hidden email]] Em nome de Frank Lammel
Enviada em: Friday, May 16, 2008 3:40 AM
Para: [hidden email]
Cc: [hidden email]
Assunto: Re: [Elecraft] RTTY Filter for K3

Hi Axel,

full ack with Joe. I use the 400 Hz 8 Pole with a DSP of about 300-350
in dual tone. Perfect!

73!
Frank, DD7ZT



Joe Subich, W4TV schrieb:

> After making extensive tests and plotting the selectivity curves
> of the 200 Hz filter in my K3, I'm convinced that it is too
> narrow for reliable weak signal RTTY operation, particularly in
> conjunction with the dual-tone filter.  
>
> The measured -6dB bandwidth of the 200 Hz crystal filter was
> 209 Hz and the composite bandwidth of the 200 Hz crystal filter,
> 200 Hz DSP and dual tone fitter was less than 170 Hz.  A standard
> 170 Hz shift 45.45 baud RTTY signal needs at least 235 Hz
> (170 + 3*22.7) and the dual tone filter represents a 220 Hz (two
> 50 Hz filters with center frequencies separated by 170 Hz).
>
> After extended discussion with a well know RTTY op and K3 beta
> tester, I believe the combination of a 300 Hz 5-pole crystal filter,
> 300 Hz DSP and the dual tone filter will have a composite -6 dB
> bandwidth of about 250 Hz - about optimum for narrow RTTY.  The
> currently available, "250," "400" or 500 Hz filters in combination
> with a 300 Hz DPS bandwidth and dual tone filter are very close to
> optimum.  
>
> 73,
>
>    ... Joe, W4TV
>      
>
>

>>
>> Hi K3-folks,
>>
>> What would be the best RTTY roofing filter for the K3? Is the
>> 400Hz 8-pole
>> filter too small and the 500Hz 5-pole filter the better choice?
>>
>> Thanks in advance for your answers.
>>
>> 73 de
>>
>> Axel, DL3ZH
>>

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[DD7ZT]

Hi Oms,

for 'each day digimode' I use mixw, for contesting N1MM with MMTTY.
Tried also DM780. Each works ufb with the K3.

73
Frank, DD7ZT



py5eg schrieb:

> Hi Frank:
> I didn't receive yet my optional filters, but I wondering what is the
> software you are using in conjunction with the K3.
> I'm using the Mixw2
> Best regards
> Oms PY5EG
>
> -----Mensagem original-----
> De: [hidden email]
> [mailto:[hidden email]] Em nome de Frank Lammel
> Enviada em: Friday, May 16, 2008 3:40 AM
> Para: [hidden email]
> Cc: [hidden email]
> Assunto: Re: [Elecraft] RTTY Filter for K3
>
> Hi Axel,
>
> full ack with Joe. I use the 400 Hz 8 Pole with a DSP of about 300-350
> in dual tone. Perfect!
>
> 73!
> Frank, DD7ZT
>
>
>
> Joe Subich, W4TV schrieb:
>
>> After making extensive tests and plotting the selectivity curves
>> of the 200 Hz filter in my K3, I'm convinced that it is too
>> narrow for reliable weak signal RTTY operation, particularly in
>> conjunction with the dual-tone filter.  
>>
>> The measured -6dB bandwidth of the 200 Hz crystal filter was
>> 209 Hz and the composite bandwidth of the 200 Hz crystal filter,
>> 200 Hz DSP and dual tone fitter was less than 170 Hz.  A standard
>> 170 Hz shift 45.45 baud RTTY signal needs at least 235 Hz
>> (170 + 3*22.7) and the dual tone filter represents a 220 Hz (two
>> 50 Hz filters with center frequencies separated by 170 Hz).
>>
>> After extended discussion with a well know RTTY op and K3 beta
>> tester, I believe the combination of a 300 Hz 5-pole crystal filter,
>> 300 Hz DSP and the dual tone filter will have a composite -6 dB
>> bandwidth of about 250 Hz - about optimum for narrow RTTY.  The
>> currently available, "250," "400" or 500 Hz filters in combination
>> with a 300 Hz DPS bandwidth and dual tone filter are very close to
>> optimum.  
>>
>> 73,
>>
>>    ... Joe, W4TV
>>      
>>
>>
>
>>> Hi K3-folks,
>>>
>>> What would be the best RTTY roofing filter for the K3? Is the
>>> 400Hz 8-pole
>>> filter too small and the 500Hz 5-pole filter the better choice?
>>>
>>> Thanks in advance for your answers.
>>>
>>> 73 de
>>>
>>> Axel, DL3ZH
>>>
>
>
> _______________________________________________
> Elecraft mailing list
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> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>

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