[Elecraft] K3: best roofing filter on RTTY

[David Cole]

Hi,
I ordered and use the 400 for RTTY, I suspect the 250 is a bit to
narrow.
-- 
Thanks and 73's,
For equipment, and software setups and reviews see:
www.nk7z.net
for MixW support see;
http://groups.yahoo.com/neo/groups/mixw/info
for Dopplergram information see:
http://groups.yahoo.com/neo/groups/dopplergram/info
for MM-SSTV see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info


On Sun, 2015-02-15 at 22:02 -0500, Dick via Elecraft wrote:
>  Hi Guys,
>  
> I'd appreciate your thoughts on the best roofing filter: 250hz  vs. 400hz, 
> for RTTY contest conditions.
>  
> While I really like the K3 on RTTY, I believe improvement  can be made to 
> my K3 RTTY reception.  Some contesters have  told me that they use the 250hz 
> roofing filter exclusively when operating  RTTY contests.  Since the actual 
> bandwidth of the 250hz roffer  filter is close to 370hz, and RTTY signals  
> are typically about 370hz wide, then the 250hz roofer along with a 400  or 
> 500hz DSP setting should be close to ideal when maximum  selectivity is 
> needed.  However, on both of  my K3's, when I switch from the 400hz roofer to the 
> 250hz roofer, the  RTTY signal is decoded a lot less often, about 25% less 
> often.   It doesn't seem like the 400hz roofer should decode 25% more often 
> than the  250hz roofer.  (but perhaps that's normal?)  
>  
> 
> Perhaps there is a receiver setting change I  can make to the K3 that will 
> improve RTTY decoding when using the 250hz  roofer?  I've tried various 
> shift settings when the 250hz roofer  is engaged and sometimes it improves RTTY 
> reception, but not  consistantly.   Perhaps there's a setting change I  can 
> make to MMTTY?  
> By the way, I'm using  both MMTTY and 2Tone software's for decoding RTTY, 
> with basically the same  results when the 250hz roofer is engaged.  
> 
>  
> Thanks in advance for your thoughts.
>  
> 73,
> Dick- K9OM
>  
> 
> 
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to dave at nk7z.net