My Five Filters
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Each morning I wake up stressed because I do not have all five filter slots populated. There is a hole in my K3 and it bothers me. I had been saving the high end for a FM filter but now decided that "No, I won't be doing FM with my K3". So, my filters are: 400 Hz, 1000 Hz, 2.7 KHz (5-p), 6 KHz.
I am thinking of adding another filter and I am thinking of the 250 Hz because I prefer CW over SSB and I think I would get more use out of that end of my filter lineup. So, is it overkill to have the 250 Hz and the 400 Hz filters in the same K3? 73, phil, K7PEH ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Not overkill at all, Phil, if you are into CW contesting. Especially
something like the 160 meter events. But I would recommend the 200 Hz 5 pole rather than the 250 Hz 8 pole. The 250 and 400 are actually pretty close in actual BW (see measured data available elsewhere). I use the 200 and 400 combo (mostly CW contesting) and am quite pleased. 73 Craig AC0DS <> So, is it overkill to have the 250 Hz and the 400 Hz filters in the same K3? ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Phil Hystad
G'morning, Phil:
After taking a look at the response curves for the filters, I chose the 5 pole 200 Hz filter to accompany the 8 pole 400 Hz filter. I find it useful in the crowded bands during the contests. 73, Ken K3IU ~~~~~~~~~~~~~~~~~~~~~~~~~~~ On 2/17/2010 9:52 AM, Phil Hystad wrote: > Each morning I wake up stressed because I do not have all five filter slots populated. There is a hole in my K3 and it bothers me. I had been saving the high end for a FM filter but now decided that "No, I won't be doing FM with my K3". So, my filters are: 400 Hz, 1000 Hz, 2.7 KHz (5-p), 6 KHz. > > I am thinking of adding another filter and I am thinking of the 250 Hz because I prefer CW over SSB and I think I would get more use out of that end of my filter lineup. > > So, is it overkill to have the 250 Hz and the 400 Hz filters in the same K3? > > 73, phil, K7PEH > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Craig Smith
Ditto. W4TV (?) measured the 250 (actually 370 Hz) versus the 200 and the latter had more rejection at ALL frequencies, even though it's only a 5-pole. I only use my 200 ~1% of the time (500 Hz 8-pole the other 99%) but there are times when it's nice to have (such as large simplex pileups). Someone previously commented on the 1000 Hz (actually ~1100 Hz) for CW. I had one but found it too wide to be of much use. If there are NOT a lot of strong signals around, the stock 2.7k will work about as well. If there ARE a lot of strong signals around, the 1000 allows too many of them to desense the rig. This is especially true if you use a low pitch as I do (3-400 Hz). In that case the bandpass is shifted upwards from 200 Hz such that signals as much as 1000 Hz above zero beat will desense the K3 (e.g. a 200-1300 Hz bandpass for a 300 Hz pitch). 73, Bill |
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> Ditto. W4TV (?) measured the 250 (actually 370 Hz) versus > the 200 and the latter had more rejection at ALL frequencies, > even though it's only a 5-pole. Actually, I compared both of my 200 Hz filters (measured) to the curves for the 250 Hz filter on the Elecraft web page: http://www.elecraft.com/K3/K3_8_pole_plots.htm specifically http://www.elecraft.com/K3/filter_plots/250.gif. The stated conclusion is correct ... my filters were 190 and 200 Hz at -6dB and 440 Hz wide at - 30dB vs. 360/525 Hz for the INRAD/Elecraft 250 Hz filter. Note, according to Wayne only the first 30 dB or so of rejection is significant as that is enough to protect the AGC and mixers and after 30 dB the DSP is the dominant bandwidth determining factor. As recommended by others, I would use 400 Hz for general CW and RTTY with the 200 Hz for critical CW only (200 Hz is too narrow for 170 Hz shift RTTY which, in theory, needs around 300 Hz to properly pass the keying sidebands). My own rigs have 13 KHz, 2.8 KHz, open, 500 Hz and 200 Hz filters. I'm waiting on Elecraft to allow use of the 13 KHz filter for AM and ESSB transmit (there is no reason to not allow it) and will eventually add the 1.5 KHz "narrow SSB" filter. If I were to do it again, I would have saved the money on the 2,8 KHz filters and gotten the 400 Hz filters instead. The savings in sticking with two stock 2.7 KHz filters (even with matching for the sub receiver) would have paid for the 13 KHz Hz and 200 Hz filters. 73, ... Joe, W4TV > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Bill W4ZV > Sent: Wednesday, February 17, 2010 10:23 AM > To: [hidden email] > Subject: Re: [Elecraft] My Five Filters > > > > > Craig D. Smith wrote: > > > > But I would recommend the 200 Hz 5 pole rather than the 250 > Hz 8 pole. > > > > Ditto. W4TV (?) measured the 250 (actually 370 Hz) versus > the 200 and the latter had more rejection at ALL frequencies, > even though it's only a 5-pole. I only use my 200 ~1% of the > time (500 Hz 8-pole the other 99%) but there are times when > it's nice to have (such as large simplex pileups). > > Someone previously commented on the 1000 Hz (actually ~1100 > Hz) for CW. I had one but found it too wide to be of much > use. If there are NOT a lot of strong signals around, the > stock 2.7k will work about as well. If there ARE a lot of > strong signals around, the 1000 allows too many of them to > desense the rig. This is especially true if you use a low > pitch as I do (3-400 Hz). > In that case the bandpass is shifted upwards from 200 Hz such > that signals as much as 1000 Hz above zero beat will desense > the K3 (e.g. a 200-1300 Hz bandpass for a 300 Hz pitch). > > 73, Bill > > -- > View this message in context: > http://n2.nabble.com/My-Five-Filters-tp4586377p4586571.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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My lineup for both RX in my K3 is
13, 2.7, 1.8, 400, 250 6, 2.7, 1.8, 400, 250 I didn't purchase the "250" 8 pole specifically as my roofer over 200/150/100/50 DSP bandwidths. I have the "400" 8-pole identified as 450 in the K3 and the "250" identified as 350. I use WIDTH 350 as my "tighter" run bandwidth. I will use DSP width of 450 when I can, to hear callers well off frequency (surprising how many there are), but will narrow to 400 then 350 when I get "crowders" up or down. I find myself using 350 more and more often as people are crowding in closer than +/- 500. With the 8 pole "250" and the DSP at 350, the steepest of skirts nearly coincide at +/- 250, allowing a small adjustment in SHIFT to make a large adjustment in "down the skirt", to put a crowder well down without losing so much up and down hearing space. I think that there are a lot of people who are fairly tone deaf (as in couldn't carry a tune in a bucket, etc) who are just never going to hear zero beat, and packet spots that are off that keep bringing calls off frequency. So we are going to continue to have off frequency callers. The real 200 of the "200" is just too narrow for running and the "400" is sometimes too broad for running. For really narrow work, the DSP has always seemed to be enough under the "250". I find DSP of 1000 under the SSB 1.8 more than adequate for casual CW tuning around. I tighten down to 450 if I call someone. So my lineup for both RX is 13, 2.7, 1.8, 400, 250 6, 2.7, 1.8, 400, 250 Anything from 2.7 to 250 might be used for diversity. For SSB contesting I can barely manage using the 1.8, but can't stand it for casual, and use the 2.7 instead. I am in awe of someone who can get voice intelligibility out of 1.5. I can't. Simple enough to try 1.5, just reducing using WIDTH. 13 for FM in one, and 6.0 for broadcast listening in the other (BC and HF bands). 73, Guy. On Wed, Feb 17, 2010 at 4:07 PM, Joe Subich, W4TV <[hidden email]> wrote: > > > > Ditto. W4TV (?) measured the 250 (actually 370 Hz) versus > > the 200 and the latter had more rejection at ALL frequencies, > > even though it's only a 5-pole. > > Actually, I compared both of my 200 Hz filters (measured) to > the curves for the 250 Hz filter on the Elecraft web page: > http://www.elecraft.com/K3/K3_8_pole_plots.htm specifically > http://www.elecraft.com/K3/filter_plots/250.gif. > > The stated conclusion is correct ... my filters were 190 and > 200 Hz at -6dB and 440 Hz wide at - 30dB vs. 360/525 Hz for > the INRAD/Elecraft 250 Hz filter. Note, according to Wayne > only the first 30 dB or so of rejection is significant as that > is enough to protect the AGC and mixers and after 30 dB the > DSP is the dominant bandwidth determining factor. > > As recommended by others, I would use 400 Hz for general CW > and RTTY with the 200 Hz for critical CW only (200 Hz is > too narrow for 170 Hz shift RTTY which, in theory, needs > around 300 Hz to properly pass the keying sidebands). > > My own rigs have 13 KHz, 2.8 KHz, open, 500 Hz and 200 Hz > filters. I'm waiting on Elecraft to allow use of the 13 KHz > filter for AM and ESSB transmit (there is no reason to not > allow it) and will eventually add the 1.5 KHz "narrow SSB" > filter. If I were to do it again, I would have saved the > money on the 2,8 KHz filters and gotten the 400 Hz filters > instead. The savings in sticking with two stock 2.7 KHz > filters (even with matching for the sub receiver) would > have paid for the 13 KHz Hz and 200 Hz filters. > > 73, > > ... Joe, W4TV > > > > > > > > -----Original Message----- > > From: [hidden email] > > [mailto:[hidden email]] On Behalf Of Bill W4ZV > > Sent: Wednesday, February 17, 2010 10:23 AM > > To: [hidden email] > > Subject: Re: [Elecraft] My Five Filters > > > > > > > > > > Craig D. Smith wrote: > > > > > > But I would recommend the 200 Hz 5 pole rather than the 250 > > Hz 8 pole. > > > > > > > Ditto. W4TV (?) measured the 250 (actually 370 Hz) versus > > the 200 and the latter had more rejection at ALL frequencies, > > even though it's only a 5-pole. I only use my 200 ~1% of the > > time (500 Hz 8-pole the other 99%) but there are times when > > it's nice to have (such as large simplex pileups). > > > > Someone previously commented on the 1000 Hz (actually ~1100 > > Hz) for CW. I had one but found it too wide to be of much > > use. If there are NOT a lot of strong signals around, the > > stock 2.7k will work about as well. If there ARE a lot of > > strong signals around, the 1000 allows too many of them to > > desense the rig. This is especially true if you use a low > > pitch as I do (3-400 Hz). > > In that case the bandpass is shifted upwards from 200 Hz such > > that signals as much as 1000 Hz above zero beat will desense > > the K3 (e.g. a 200-1300 Hz bandpass for a 300 Hz pitch). > > > > 73, Bill > > > > -- > > View this message in context: > > http://n2.nabble.com/My-Five-Filters-tp4586377p4586571.html > > Sent from the Elecraft mailing list archive at Nabble.com. > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Phil Hystad
Phil,
Don't get so stressed. My K3 has 3 open filter slots, and it does not concern me at all. How much serious contesting do you do - how much serious DX Chasing? Consider my logic: The DSP filtering alone is really good and will handle conditions under more casual situations than the above. Just dial in the filtering you want. The "rub" comes in when there are a lot of strong signals in the Roofing filter passband. You may not hear them with the DSP filtering tightened up, but they will activate the hardware AGC and will de-sense the receiver. The reality of that happening are not usually present in normal operating, but will be present in serious contest and DX Chasing situations. My opinions: 1) A wide CW roofing filter is of little value. There will be so many signals in the passband that at least one is likely to activate the hardware AGC, so I figure that the normal 2.7/2.8 kHz filter with DSP set somewhere between 700 and 1000 Hz width will be about as good as the 1000 Hz filter. 2) If you are a SSB contester, go for the 1.8 filter (or even the 1.5 from Inrad) if you want to operate in extreme SSB conditions. 3) For CW contesting and DX Chasing, you will likely want a roofer in the 400 Hz or even 250 Hz range - which one depends on how much you are willing to dig for reception under crowded conditions. As the filter gets more narrow, the more critical (i.e. slowly) one must tune, or the desired signal will suddenly disappear outside the passband. 4) For Data modes where one tunes with the VFO rather than clicking on a waterfall display, a 400 Hz filter is a good thing to have - some would argue that a filter in the 200 to 300 Hz range would be better, and that is logical too - which depends on how critical you wish to tune and how important that elusive contact is to you. OK, I have not said which filters to use, but for me, the ideal set would be 13 kHz (discard if you don't want to do FM), the 6 kHz filter if you want to transmit AM or ESSB (the 6 kHz is good for SWLing, although the 13 kHz will do fine for that too). The 2.7 or 2.8 kHz filter is required. Then the 1.8 (alternately the 1.5) for SSB contesting/DXing. The 400 Hz filter for normal CW, although for general tuning I like 700 Hz - do that with the 2.7, 1.8, or 1.5 kHz filter and the narrowed DSP filter. For extreme CW or data mode work, any roofing filter in the 200 to 300 Hz range will do for me. That fills the slots - 13 kHz, 6 kHz, 2.7/2.8, 1.8/1.5 and 400/200-300 range. If you do not want FM, then you will have 1 empty slot. OK, that is the ideal for me, and I am building on it - I currently have the 13 kHz and the 2.7 kHz filters installed. Right now, I am not interested in serious DXing or contesting, so until that bug bites me, the other slots will remain empty. Those are my thoughts and the reasons I have chosen this path - YMMV, make up your own criteria based on your operating desires. 73, Don W3FPR Phil Hystad wrote: > Each morning I wake up stressed because I do not have all five filter slots populated. There is a hole in my K3 and it bothers me. I had been saving the high end for a FM filter but now decided that "No, I won't be doing FM with my K3". So, my filters are: 400 Hz, 1000 Hz, 2.7 KHz (5-p), 6 KHz. > > I am thinking of adding another filter and I am thinking of the 250 Hz because I prefer CW over SSB and I think I would get more use out of that end of my filter lineup. > > So, is it overkill to have the 250 Hz and the 400 Hz filters in the same K3? > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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