Dual PB filter
Locked
 
|
Anybody out there playing with this feature or actually used it in a contest? What are your experiences?
Playing with it yielded the following:. 1) Narrower CW filters can't be used (at least not my 400 Hz and narrower filters). The wings are outside the narrow filter passband. 2) For me that meant the 1.8KHz roofing filter was used. It seems like that defeats the purpose of having a K3. In a contest situation, I would certainly like as many rock crusher signal outside the roofing filter passband as possible. It would suggest one might consider the 1 KHz roofing filter, if you want to seriously use this option. If there existed some intermediate (say 700Hz) or variable roofing filter, what would it's width have to be to include the wings and be used for dual PB filtering? de Brian/K3KO |
|
|
It has really saved the day on a couple of RTTY QSO's. That is the
only place I have used it. David Wilburn K4DGW alsopb wrote: > Anybody out there playing with this feature or actually used it in a contest? > What are your experiences? > > Playing with it yielded the following:. > > 1) Narrower CW filters can't be used (at least not my 400 Hz and narrower > filters). The wings are outside the narrow filter passband. > 2) For me that meant the 1.8KHz roofing filter was used. > > It seems like that defeats the purpose of having a K3. In a contest > situation, I would certainly like as many rock crusher signal outside the > roofing filter passband as possible. > > It would suggest one might consider the 1 KHz roofing filter, if you want to > seriously use this option. > > If there existed some intermediate (say 700Hz) or variable roofing filter, > what would it's width have to be to include the wings and be used for dual > PB filtering? > > de Brian/K3KO Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by alsopb
The narrowest setting of DUAL PB is set to 600 Hz by the DSP firmware. If you have a 500 Hz filter (actual BW ~560 Hz), you can adjust its set point to 600 Hz so that it's enabled at the narrowest DUAL PB setting. You could do the same with the 400 Hz but 600 Hz is quite a bit above that filter's 430 Hz BW, which might cause other undesired issues in normal operation. 73, Bill |
|
|
In reply to this post by dave.wilburn
Just looked at what this Dual PB filter was doing with SPECTROGRAM.
Set up with a width of 600Hz and a 1.8 KHz roofing filter. DPB off and on. The 600 Hz alone has the normal filter passband shape. DPB on gives a narrower center filter less than 200 Hz wide and two augmented wings down about 30db filling out the rest of the normal filter passband. This explains why DPB sounded quietern to one poster. I suspect turning the K3 width setting to 200 Hz would have the same quieting effect. 73 de Brian/K3KO David Wilburn wrote: > It has really saved the day on a couple of RTTY QSO's. That is the > only place I have used it. > > David Wilburn > K4DGW > > > alsopb wrote: > >> Anybody out there playing with this feature or actually used it in a >> contest? What are your experiences? >> >> Playing with it yielded the following:. >> >> 1) Narrower CW filters can't be used (at least not my 400 Hz and >> narrower >> filters). The wings are outside the narrow filter passband. >> 2) For me that meant the 1.8KHz roofing filter was used. >> >> It seems like that defeats the purpose of having a K3. In a contest >> situation, I would certainly like as many rock crusher signal outside >> the >> roofing filter passband as possible. >> >> It would suggest one might consider the 1 KHz roofing filter, if you >> want to >> seriously use this option. >> >> If there existed some intermediate (say 700Hz) or variable roofing >> filter, what would it's width have to be to include the wings and be >> used for dual >> PB filtering? >> >> de Brian/K3KO > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by dave.wilburn
Two different filters although both are activated by the DUAL PB
hold-button, depending on MODE. In RTTY it is the Dual-Tone Filter, two 50 Hz DSP filters spaced 170 Hz apart. In CW, it is a two level filter with two widths, 150 Hz and 600 Hz as I recall. The passband of the 600 Hz filter is 20 dB down which provides the skirts to hear nearby signals without having them dominate the signal(s) you focus on in the 150 Hz filter. As for the choice of roofing filter, it needs to be wider than 600 Hz. So, yes, a 700 Hz crystal filter would give the most DSP protection from strong signals outside the 600 Hz bandwidth. 73, Ed - W0YK > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of David Wilburn > Sent: Wednesday, 30 July, 2008 05:37 > To: Elecraft Discussion List > Subject: Re: [Elecraft] Dual PB filter > > It has really saved the day on a couple of RTTY QSO's. That > is the only place I have used it. > > David Wilburn > K4DGW > > > alsopb wrote: > > Anybody out there playing with this feature or actually > used it in a contest? > > What are your experiences? > > > > Playing with it yielded the following:. > > > > 1) Narrower CW filters can't be used (at least not my 400 Hz and > > narrower filters). The wings are outside the narrow filter > passband. > > 2) For me that meant the 1.8KHz roofing filter was used. > > > > It seems like that defeats the purpose of having a K3. In > a contest > > situation, I would certainly like as many rock crusher > signal outside > > the roofing filter passband as possible. > > > > It would suggest one might consider the 1 KHz roofing > filter, if you > > want to seriously use this option. > > > > If there existed some intermediate (say 700Hz) or variable roofing > > filter, what would it's width have to be to include the > wings and be > > used for dual PB filtering? > > > > de Brian/K3KO > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |