Guys - this thread has been formally closed. (both the 700 hz and ESSB sub threads).
Please take further discussion off list. 73, Eric Elecraft List Moderator - really! www.elecraft.com _..._ On Sep 21, 2010, at 6:43 PM, "Joe Subich, W4TV" <li...@subich.com> wrote: > > Jeff, > >> Because it's illegal. > > The "roofing filter" does not set the transmitted bandwidth - that > is controlled in the DSP modulator. The only purpose for roofing > filter in transmit is to remove the image of the IF and the FM filter > has more than sufficient skirt selectivity for that job (the image > is 30 KHz away). > >>> Thus, anything more than the 3KHz SSB bandwidth is against the >> laws that govern us. > > Incorrect in the USA. There is no statutory maximum bandwidth though > my personal opinion is that anything more than 2.8KHz (200 Hz - 3000 > Hz audio) is "bad practice." Double sideband AM will require twice > the highest modulating frequency so 6 KHz is appropriate. However, > again, it's the DSP that sets that bandwidth *not* the roofing filter. > > 73, > > ... Joe, W4TV > > > On 9/21/2010 8:19 PM, Jeff Cochrane - VK4BOF wrote: >> Hi Joe et al, >> I'm going to hazzard a guess here as to why Elecraft dont allow the 13KHz >> filter for AM/ESSB TX. >> >> Because it's illegal. >> SSB is called mode A3J in most of the legal documents that govern our hobby. >> The reason why the mode is called A3J in all the legal stuff is that the 3 >> is the maximum bandwidth in khz that is permitted.) >> Thus, anything more than the 3KHz SSB bandwidth is against the laws that >> govern us. >> >> The F.C.C. in the US of A and here in Australia, A.C.M.A. both allow a >> maximum of 3KHz for SSB TX bandwidth on any HF band. >> So it would be a fair bet then that because the K3 is a FCC type approved >> radio that part of that type approval includes that it must not transmit SSB >> bandwidths that are wider than permitted. >> >> My $0.02c worth (Plus GST/VAT/Sales Tax as applicable) >> >> >> Jeff Cochrane - VK4BOF >> Innisfail, QLD, Australia >> Elecraft K3# 4257 >> >> ----- Original Message ----- >> From: Joe Subich, W4TV >> To: elecraft@mailman.qth.net >> Sent: Wednesday, September 22, 2010 9:44 AM >> Subject: Re: [Elecraft] 700 Hz roofing filters >> >> >> >> In general I agree with Wayne although I prefer to have a more >> narrow bandwidth option for SSB (1.8 or 1.5 KHz). In order to >> make room for the 1.5/1.8 KHz filter, I deleted the AM filter >> and use only the FM filter for the "low priority" modes wider >> than 2.8 KHz. However, it continues to frustrate me that >> Elecraft have *STILL* not allowed us to use the 13 KHz filter >> for AM/ESSB transmit (officially). >> >> In any case, given the measured performance of the INRAD/Elecraft >> "250 Hz" filter (about 350 to 375 Hz), I can certainly see the >> utility of something like: >> >> FL1 13 kHz (FM/AM/ESSB) >> FL2 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning) >> FL3 1.8 or 1.5 KHz (Narrow SSB and wide data modes) >> FL4 700 Hz (casual/normal CW/DATA) >> FL5 350 Hz (Narrow CW/RTTY in heavy QRM) >> >> While the "350 Hz" filter would lack the absolute selectivity of >> the Elecraft 200 Hz 5-pole filter, it would be nearly optimum >> for 45.45 baud RTTY and still provide a useful "narrow CW" option. >> >> 73, >> >> ... Joe, W4TV >> >> On 9/21/2010 6:07 PM, Wayne Burdick wrote: >>> 700 Hz is a useful CW/DATA filter bandwidth, certainly. I'm not >>> surprised that some K3 owners are interested in this. >>> >>> Personally, I prefer much narrow CW/DATA bandwidths, and I use all >>> modes. The lineup I use (and generally recommend) is: >>> >>> FL1 13 kHz (FM) >>> FL2 6 kHz (AM/ESSB) >>> FL3 2.7 or 2.8 kHz (SSB and casual CW/DATA tuning) >>> FL4 400 or 500 Hz (normal CW/DATA) >>> FL5 200 Hz (CW/DATA in heavy QRM) >>> >>> 73, >>> Wayne >>> N6KR >>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:Elecraft@mailman.qth.net >>> >>> 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:Elecraft@mailman.qth.net >> >> 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:Elecraft@mailman.qth.net >> >> 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:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
