Roofing Filter question
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I have a K3/10 on order. I have used my K2 for over a year and find the filters to be very good. I operate 90% on the time on QRP CW. I'm looking for opinions on which roofing filters I might include.
73,72 Mike, W9QS EX: KN6TBP (1956), K1DGQ, DL4KM, K5LJN, W9FRR, W9KVF K2, OHR500, Norcal 20, SP1 Fists #12327, FP #268, OOTC #4423, QRPARCI #9521 _______________________________________________ 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 |
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Maybe none. You get great filtering out of the DSP. The roofing filters
are most helpful when very strong signals are present nearby. Operating mostly QRP, you might never run into that problem. k4ia Buck Fredericksburg, VA K3# 101 In a message dated 12/18/2008 9:04:42 A.M. Eastern Standard Time, [hidden email] writes: I have a K3/10 on order. I have used my K2 for over a year and find the filters to be very good. I operate 90% on the time on QRP CW. I'm looking for opinions on which roofing filters I might include. 73,72 Mike, W9QS EX: KN6TBP (1956), K1DGQ, DL4KM, K5LJN, W9FRR, W9KVF K2, OHR500, Norcal 20, SP1 Fists #12327, FP #268, OOTC #4423, QRPARCI #9521 _______________________________________________ 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 **************One site keeps you connected to all your email: AOL Mail, Gmail, and Yahoo Mail. Try it now. (http://www.aol.com/?optin=new-dp&icid=aolcom40vanity&ncid=emlcntaolcom00000025) _______________________________________________ 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 |
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In reply to this post by Mike, W9QS
Hi Mike,
Buck may be right, maybe none. But, based on my first experience with the K3 in the fox hunt the other night, if you have to buy one, a 400hz filter might be a good choice. I can see where it might make a difference when you find the fox nudged right next to a strong non QRP station. Either way the K3 is a big step up from the K2. I haven't found myself wanting a tighter filter yet. Good luck in the 40M tonight. Work got the way tonight and I'm 4,000 miles away from my rig in Switzerland. I hope I got to help you spend your money. HI! Chuck HB9/K4QS
From: Mike, W9QS <[hidden email]> To: elecraft <[hidden email]> Sent: Thu, 18 Dec 2008 9:03 am Subject: [Elecraft] Roofing Filter question I have a K3/10 on order. I have used my K2 for over a year and find the filters Listen to 350+ music, sports, & news radio stations – including songs for the holidays – FREE while you browse. Start Listening Now! _______________________________________________ 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 |
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In reply to this post by Mike, W9QS
I would echo the other responses that you may well not need any
narrower roofing filters. You might try using just the stock 2.7 kHz filter for a while and see how it goes. I recently added the 400 Hz filter and so far, it makes virtually no difference EXCEPT in the case where there's a strong signal within +/- 1 kHz or so of the station I'm trying to work. Note that a "strong signal" might be another ham station, a broadcast station, RFI, etc. If you're interested in listening to shortwave or AM broadcast stations on your K3, then you might consider the 6 kHz (AM) or 13 kHz (FM) filters. Of course, you'll also need those filters if you intend to operate those modes. There's a good article on the Elecraft web site about roofing filters. Check out http://www.elecraft.com/K3/Roofing_Filters.htm 73 -- Joe KB8AP On Dec 18, 2008, at 6:03 AM, Mike, W9QS wrote: > I have a K3/10 on order. I have used my K2 for over a year and find > the filters to be very good. I operate 90% on the time on QRP CW. > I'm looking for opinions on which roofing filters I might include. _______________________________________________ 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 |
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In reply to this post by Mike, W9QS
I have a K3/10 which I use for CW. I got the 13 KHz (for AM bcst) and
500 Hz filters, which I'm happy with. I could get a narrower one but just haven't felt the need for it yet. 73, Drew AF2Z On Thu, 18 Dec 2008 06:03:43 -0800 (PST), Mike, W9QS wrote: >I have a K3/10 on order. I have used my K2 for over a year and find the filters to be very good. I operate 90% on the time on QRP CW. I'm looking for opinions on which roofing filters I might include. > > > >73,72 > >Mike, W9QS >EX: KN6TBP (1956), K1DGQ, DL4KM, K5LJN, W9FRR, W9KVF > _______________________________________________ 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 |
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In reply to this post by Joe Planisky
On Thu, 18 Dec 2008 08:14:51 -0800, Joe Planisky wrote:
>I recently added the 400 Hz >filter and so far, it makes virtually no difference EXCEPT in the case >where there's a strong signal within +/- 1 kHz or so of the station >I'm trying to work. Note that a "strong signal" might be another ham >station, a broadcast station, RFI, etc. Yes. Remember that the IF in the K3 has EXTENSIVE IF filtering that perform the function of crystal filters in older radios. Those filters can be adjusted (front panel knob) to virtually any bandwidth between 50 Hz and 6 kHz, and are the equivalent of a selectable filter bank of 20 or more expensive filters! The roofing filter simply sits IN FRONT OF these IF filters. It protects them from overload, AND provides additional skirt selectivity. The radio works fine for routine use with nothing more than the stock 2.7 kHz roofing filter. The roofing filters simply improve performance under difficult conditions. I own two K3s, one with 400 Hz and 1.8 kHz filters, the other with only a 400 Hz filter. I operated from two QTHs during the SSB weekend of Sweepstakes. At one QTH I had the 1.8 kHz filter, at the other I did not. The 1.8 kHz filter helped, but I was still quite happy with the radio that didn't have the 1.8 kHz filter. 73, Jim K9YC _______________________________________________ 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 |
Re: Roofing Filter question (+ some K3 receiver philosophy)
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In reply to this post by Joe Planisky
Mike, W9QS wrote:
> I have a K3/10 on order. I have used my K2 for over a year and find > the filters to be very good. I operate 90% on the time on QRP CW. > I'm looking for opinions on which roofing filters I might include. Mike, If you operate CW at all, you'll almost surely want at least one narrow filter. Either our 400 Hz or 500 Hz filter would be a great all-around choice. I'm *not* just trying to sell filters :) The reason you need a narrow filter is that the K3's entire receiver architecture is based on the premise that the 1st I.F. filter should be close to the communications bandwidth in use. This is what sets the K3 apart from other transceivers that use an up-conversion architecture, and thus very wide front-end filtering (at least in relation to CW or data modes -- 3 to 15 kHz). The K2 has a similar architecture to the K3. In that case, a single crystal filter covers bandwidths from about 200 to 2000 Hz. The K3 builds on this concept, using multiple fixed-bandwidth filters with much lower ripple, stronger signal handling in all stages, and a synthesizer with extremely low phase noise. But both receivers use low-noise 2nd IFs that really should be protected from out-of-band signals. (In this case, out of band means "outside the crystal filter.") If you're a K2 owner, you're already use to the protection you get from narrow filtering. You'll probably want that same kind of signal handling performance in your K3 if you use it on Field Day, or during a contest, or just when the band is open and signals are strong. If you look at Sherwood's receiver performance chart (http://www.sherweng.com/table.html), you'll see that the K2 has respectable IMD dynamic range at 2 kHz: close to that of the Icom IC-7800 (at 1/10th the price :) But the K3 is at the top of the chart -- 15 to 20 dB better, depending on the filter bandwidth. To obtain this benefit from having a K3, IMHO you really need narrow filtering. 73, Wayne N6KR --- 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 |
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In reply to this post by Jim Brown-10
Joe,
I agree with Jim's advice here. I have used my K3 several times in CW contests from Aruba as P49Y, most recently on a 40m single band operation in CQWW, on a very crowded band. For that kind of usage, I think the narrow CW filter is advisable. With it, I was never bothered by signals even a few hundred Hertz away (unless they had clicks extending into my passband, of course), and I think the DSP along with the 2.7 kHz filter wouldn't have stopped the loudest signals. BTW, one think that makes the K3 such a great run radio is that in those circumstances you also have a very clean passband, devoid of the kind of digital artifacts that I hear, for example, on my 756 Pro2 on a crowded band. 73, andy, ae6y ----- Original Message ----- From: "Jim Brown" <[hidden email]> To: "Elecraft List" <[hidden email]> Sent: Thursday, December 18, 2008 8:52 AM Subject: Re: [Elecraft] Roofing Filter question > On Thu, 18 Dec 2008 08:14:51 -0800, Joe Planisky wrote: > >>I recently added the 400 Hz >>filter and so far, it makes virtually no difference EXCEPT in the case >>where there's a strong signal within +/- 1 kHz or so of the station >>I'm trying to work. Note that a "strong signal" might be another ham >>station, a broadcast station, RFI, etc. > > Yes. Remember that the IF in the K3 has EXTENSIVE IF filtering that > perform the function of crystal filters in older radios. Those filters > can be adjusted (front panel knob) to virtually any bandwidth between 50 > Hz and 6 kHz, and are the equivalent of a selectable filter bank of 20 > or more expensive filters! The roofing filter simply sits IN FRONT OF > these IF filters. It protects them from overload, AND provides > additional skirt selectivity. > > The radio works fine for routine use with nothing more than the stock > 2.7 kHz roofing filter. The roofing filters simply improve performance > under difficult conditions. I own two K3s, one with 400 Hz and 1.8 kHz > filters, the other with only a 400 Hz filter. I operated from two QTHs > during the SSB weekend of Sweepstakes. At one QTH I had the 1.8 kHz > filter, at the other I did not. The 1.8 kHz filter helped, but I was > still quite happy with the radio that didn't have the 1.8 kHz filter. > > 73, > > Jim K9YC > > > _______________________________________________ > 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 |
Re: Re: Roofing Filter question (+ some K3 receiver philosophy)
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In reply to this post by wayne burdick
wayne burdick wrote:
> Mike, W9QS wrote: > >> I have a K3/10 on order. I have used my K2 for over a year and find >> the filters to be very good. I operate 90% on the time on QRP CW. >> I'm looking for opinions on which roofing filters I might include. > > Mike, > > If you operate CW at all, you'll almost surely want at least one > narrow filter. Either our 400 Hz or 500 Hz filter would be a great > all-around choice. > > I'm *not* just trying to sell filters :) The reason you need a > narrow filter is that the K3's entire receiver architecture is based > on the premise that the 1st I.F. filter should be close to the > communications bandwidth in use. This is what sets the K3 apart from > other transceivers that use an up-conversion architecture, and thus > very wide front-end filtering (at least in relation to CW or data > modes -- 3 to 15 kHz). > > The K2 has a similar architecture to the K3. In that case, a single > crystal filter covers bandwidths from about 200 to 2000 Hz. The K3 > builds on this concept, using multiple fixed-bandwidth filters with > much lower ripple, stronger signal handling in all stages, and a > synthesizer with extremely low phase noise. But both receivers use > low-noise 2nd IFs that really should be protected from out-of-band > signals. (In this case, out of band means "outside the crystal filter.") > > If you're a K2 owner, you're already use to the protection you get > from narrow filtering. You'll probably want that same kind of signal > handling performance in your K3 if you use it on Field Day, or during > a contest, or just when the band is open and signals are strong. > > If you look at Sherwood's receiver performance chart > (http://www.sherweng.com/table.html), you'll see that the K2 has > respectable IMD dynamic range at 2 kHz: close to that of the Icom > IC-7800 (at 1/10th the price :) But the K3 is at the top of the chart > -- 15 to 20 dB better, depending on the filter bandwidth. To obtain > this benefit from having a K3, IMHO you really need narrow filtering. > > 73, > Wayne > N6KR > > --- > > 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 > > that a narrower filter will be good for crowded CW with strong stations, but was waiting for the release of the "variable" filter mentioned on the website. Is there any more recent information on the status of that option? MNI TNX and VY 73, Lance -- Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8) P.O. Box 73 Frenchtown, MT 59834 USA QTH: DN27UB TEL: (406) 626-5728 URL: http://www.bigskyspaces.com/w7gj 2m DXCC #11/6m DXCC #815 _______________________________________________ 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 |
Re: Variable-BW crystal filters
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In reply to this post by wayne burdick
Lance Collister, W7GJ wrote:
> I got the 6, 2.7 (standard), and 1.8 KHz filters in my K3. I realize > that a narrower filter will be good for crowded CW with strong > stations, but was waiting for the release of the "variable" filter > mentioned on the website. Is there any more recent information on the > status of that option? Hi Lance, Variable-passband CW filters are still under development. (We raised the bar pretty high with our fixed filters, and we're trying to make sure it stays high.) We're looking at various bandwidth possibilities for these. One likely candidate is 300-800 Hz or so, in 8 discrete steps. We'll post details when we get there. 73, Wayne N6KR --- 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 |
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wayne burdick wrote:
> Lance Collister, W7GJ wrote: > >> I got the 6, 2.7 (standard), and 1.8 KHz filters in my K3. I realize >> that a narrower filter will be good for crowded CW with strong >> stations, but was waiting for the release of the "variable" filter >> mentioned on the website. Is there any more recent information on >> the status of that option? > > Hi Lance, > > Variable-passband CW filters are still under development. (We raised > the bar pretty high with our fixed filters, and we're trying to make > sure it stays high.) > > We're looking at various bandwidth possibilities for these. One likely > candidate is 300-800 Hz or so, in 8 discrete steps. We'll post details > when we get there. > > 73, > Wayne > N6KR > > --- > > http://www.elecraft.com > > > look forward to hearing more as it progresses ;-) GL and VY 73, Lance -- Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8) P.O. Box 73 Frenchtown, MT 59834 USA QTH: DN27UB TEL: (406) 626-5728 URL: http://www.bigskyspaces.com/w7gj 2m DXCC #11/6m DXCC #815 _______________________________________________ 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 |
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In reply to this post by Mike, W9QS
>I have a K3/10 on order. I have used my K2 for over a year and find >the filters to be very good. I operate 90% on the time on QRP >CW. I'm looking for opinions on which roofing filters I might include. Unless you're contesting or dealing with DX pileups, probably none. The default 2.7 kc filter works fine. Paul N4LCD _______________________________________________ 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 |
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In reply to this post by Mike, W9QS
>I have a K3/10 on order. I have used my K2
for over a year and find
>the filters to be very good. I operate 90% on the time on QRP >CW. I'm looking for opinions on which roofing filters I might include. Unless you're contesting or dealing with DX pileups, probably none. The default 2.7 kc filter works fine. One of the reasons I purchased a K3 was that
it had 5 roofing filter slots and
a whole slew of filters available to
fill them up. When my K3 kit arrived in June,
it came with only the 2.7 KHz filter-- my CW
filters were on back order.
I notice a huge difference when I
installed the 400 Hz filter.
Right now, I own two SSB filters and four CW
filters, and am evaluating which
three of the four CW filters I want to
keep.
My application is mainly DX
pileups, sometimes along with some close
neighbors.
73,
Chuck NI0C
K2/10 s/n 5853
K3/100 s/n 1061
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