K3: just how wide is it?
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Recently, they guys at Aptos said:
[snip] The pick-off point for the K3's buffered I.F. output -- right at the output of the 1st mixer's post-amp stage -- was selected to give the widest possible bandwidth. Thus there is no filtering of any kind from here to the BNC jack on the KXV3. This creates the opportunity to do *very* wide spectral sweeps, if required -- limited only by the bandwidth of the K3's band-pass filters. [snip] OK...just how wide is the bandwidth when "limited by the K3's BP filters? Thanks, de Doug KR2Q _______________________________________________ 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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Hi Doug,
> OK...just how wide is the bandwidth when "limited by the K3's BP filters? For what it's worth... A quick and very dirty attempt to "simulate" one of the filters using Elsie 2.12 (free version) gave me in the 10m band filter a -3dB width of roughly 2.7MHz, after some tuning -> 40pF trimmers to 32pF. I assumed a Q of 1000 for the capacitors and 200 for the inductors. Maybe using Elsie or the AADE filter designer might help give you a rough idea, if you can't do simulations with Spice. vy 73 de toby _______________________________________________ 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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It's probably too early in the morning for Larry, N8LP, to be up, so
I'll mention that he has measured K3 RF filter bandwidth data posted at http://www.telepostinc.com/K3_Stuff.html. Jack K8ZOA [hidden email] wrote: > Hi Doug, > >> OK...just how wide is the bandwidth when "limited by the K3's BP >> filters? > > For what it's worth... > > A quick and very dirty attempt to "simulate" one of the filters using > Elsie 2.12 (free version) gave me in the 10m band filter a -3dB width > of roughly 2.7MHz, after some tuning -> 40pF trimmers to 32pF. I > assumed a Q of 1000 for the capacitors and 200 for the inductors. > > Maybe using Elsie or the AADE filter designer might help give you a > rough idea, if you can't do simulations with Spice. > > vy 73 de toby > > _______________________________________________ > 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 |
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In reply to this post by DOUGLAS ZWIEBEL
From a previous post by Eric: The K3 IF output is derived before the roofing IF filters and its bandwidth is only limited by the width of the front end bandpass LC filters, which are typically several hundred kHz wider than the ham band you are operating on. 73, Eric WA6HHQ |
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In reply to this post by Jack Smith-6
Hi Jack. I've been up for awhile ;-)
For those who are interested, the data was taken from the Rx antenna input to the IF output. The scales are either 5dB or 10dB/ vertical division, as indicated in the legend at the top of each chart. The markers are at roughly the -3dB points. The behavior of the 40m filter is caused by the 8.215MHz notch filter. 73, Larry N8LP Jack Smith wrote: > It's probably too early in the morning for Larry, N8LP, to be up, so > I'll mention that he has measured K3 RF filter bandwidth data posted > at http://www.telepostinc.com/K3_Stuff.html. > > Jack K8ZOA > > > > [hidden email] wrote: >> Hi Doug, >> >>> OK...just how wide is the bandwidth when "limited by the K3's BP >>> filters? >> >> For what it's worth... >> >> A quick and very dirty attempt to "simulate" one of the filters using >> Elsie 2.12 (free version) gave me in the 10m band filter a -3dB width >> of roughly 2.7MHz, after some tuning -> 40pF trimmers to 32pF. I >> assumed a Q of 1000 for the capacitors and 200 for the inductors. >> >> Maybe using Elsie or the AADE filter designer might help give you a >> rough idea, if you can't do simulations with Spice. >> >> vy 73 de toby >> >> _______________________________________________ >> 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 |
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In reply to this post by Jack Smith-6
Very cool!! Now I'd be interested to see what those measurements look like
with the general coverage receive board installed to see how much it truly doesn't affect performance. -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Jack Smith Sent: Friday, February 08, 2008 6:01 AM To: [hidden email] Cc: Larry Phipps; [hidden email] Subject: Re: [Elecraft] K3: just how wide is it? It's probably too early in the morning for Larry, N8LP, to be up, so I'll mention that he has measured K3 RF filter bandwidth data posted at http://www.telepostinc.com/K3_Stuff.html. Jack K8ZOA [hidden email] wrote: > Hi Doug, > >> OK...just how wide is the bandwidth when "limited by the K3's BP >> filters? > > For what it's worth... > > A quick and very dirty attempt to "simulate" one of the filters using > Elsie 2.12 (free version) gave me in the 10m band filter a -3dB width > of roughly 2.7MHz, after some tuning -> 40pF trimmers to 32pF. I > assumed a Q of 1000 for the capacitors and 200 for the inductors. > > Maybe using Elsie or the AADE filter designer might help give you a > rough idea, if you can't do simulations with Spice. > > vy 73 de toby > > _______________________________________________ > 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 _______________________________________________ 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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I ordered the option a few days ago, Brett, but haven't received it yet.
73, Larry N8LP Brett Howard wrote: > Very cool!! Now I'd be interested to see what those measurements look like > with the general coverage receive board installed to see how much it truly > doesn't affect performance. > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Jack Smith > Sent: Friday, February 08, 2008 6:01 AM > To: [hidden email] > Cc: Larry Phipps; [hidden email] > Subject: Re: [Elecraft] K3: just how wide is it? > > It's probably too early in the morning for Larry, N8LP, to be up, so > I'll mention that he has measured K3 RF filter bandwidth data posted at > http://www.telepostinc.com/K3_Stuff.html. > > Jack K8ZOA > > > > [hidden email] wrote: > >> Hi Doug, >> >> >>> OK...just how wide is the bandwidth when "limited by the K3's BP >>> filters? >>> >> For what it's worth... >> >> A quick and very dirty attempt to "simulate" one of the filters using >> Elsie 2.12 (free version) gave me in the 10m band filter a -3dB width >> of roughly 2.7MHz, after some tuning -> 40pF trimmers to 32pF. I >> assumed a Q of 1000 for the capacitors and 200 for the inductors. >> >> Maybe using Elsie or the AADE filter designer might help give you a >> rough idea, if you can't do simulations with Spice. >> >> vy 73 de toby >> >> _______________________________________________ >> 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 > > > 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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