> > This is as expected since the FM filter should be at least -60 > > dB at +/-23 (2:1 shape factor) with an ultimate attenuation > > of at least -100 dB.
Correction ... +/- 26 KHz or a 2:1 shape factor. However for comparison, Inrad's six pole front end filters for 40 meters are 15 KHz wide (+/- 7.5 KHz) at 1 dB and 32 KHz (+/- 16 KHz) at - 60 dB or 20 KHz ((+/- 10 KHz) at -1 dB and 45 KHz (+/- 22.5 KHz) at - 60 dB. Converting to a 6:60 framework makes the shape factor around 1.8:1. 73, ... Joe, W4TV > -----Original Message----- > From: Stewart Baker [mailto:[email protected]] > Sent: Thursday, July 09, 2009 10:35 AM > To: [email protected]; 'Brett Howard'; 'Bob Cunnings' > Cc: [email protected] > Subject: Re: [Elecraft] K3 Filter Question > > > I agree. > The cost of the K3 filters is now so high in the UK, that I > want to get away with the minimum number necessary. > > 73 > Stewart G3RXQ > On Thu, 9 Jul 2009 10:00:42 -0400, Joe Subich, W4TV wrote: > > > >> I wonder if there is any possibility of allowing AM TX and/or ESSB > >> via the FM filter... > > > > It is theoretically possible to transmit AM and ESSB through the FM > > filter but the K3 is currently configured to prohibit AM and ESSB > > transmit unless the 6 KHz filter is used. I have transmitted using > > the FM filter by setting the K3 as if the FM filter was an > AM filter > > but then I can not transmit FM without resetting the filter set-up. > > > > Elecraft will argue that the 6 KHz filter is necessary to prevent > > transmitted images (the DSP IF is 15 KHz, the image is 30 KHz away > > from the transmit frequency). However, I can not measure > any image - > > to -120 dB from the CW level - when looking at the > transmitter output > > with a directional coupler using the SDR-IQ as a spectrum > analyzer. > > This is as expected since the FM filter should be at least -60 > > dB at +/-23 (2:1 shape factor) with an ultimate attenuation > > of at least -100 dB. > > > > It would certainly be nice if the "6 KHz" restriction was removed. > > > > 73, > > > > ... Joe, W4TV > > > > > >> -----Original Message----- > >> From: [email protected] > >> [mailto:[email protected]] On Behalf Of Brett Howard > >> Sent: Thursday, July 09, 2009 2:21 AM > >> To: Bob Cunnings > >> Cc: [email protected] > >> Subject: Re: [Elecraft] K3 Filter Question > >> > >> > >> I forgot to go back to that... I was thrown off by the comment on > >> the order page that said you only need one of each filter for > >> transmit. I know that doesn't fully say what I was hoping for > >> though.... > >> > >> I wonder if there is any possibility of allowing AM TX and/or ESSB > >> via the FM filter... As I'd like to have maximum flexibility but > >> only have one slot left because of the way I have setup > the radio for > >> what I spend most of my time doing. > >> > >> Thanks for the assistance gentlemen. > >> > >> ~Brett > >> > >> On Thu, 2009-07-09 at 00:13 -0600, Bob Cunnings wrote: > >> > Manual, pg 74: > >> > > >> > "Rule #1: If you plan to use a particular filter for both > >> transmitting > >> > and receiving (main receiver), you'll need to install it > on the RF > >> > board. You can optionally install a filter of the same > or similar > >> > bandwidth on the sub receiver for receive-only use. (This is > >> > recommended since it will keep the receivers identical.)" > >> > > >> > Bob NW8L > >> > > >> > On Wed, Jul 8, 2009 at 11:31 PM, Brett > >> Howard<[email protected]> > >> > wrote: > >> > > Ok so I'm curious if I'll be able to do what I'd like. > >> I'd like to > >> > > setup my K3 for maximum flexibility. At the moment I > have these > >> > > filters. > >> > > > >> > > 2.8Khz > >> > > 1.8Khz > >> > > 1Khz > >> > > 250Hz > >> > > > >> > > These 4 filters are duplicated in the lower 4 slots of both > >> > > receivers. I'd like to have the ability to do AM and FM > >> both TX and > >> > > RX in this radio. Can I add the AM filter and KBPF into > >> the main RX > >> > > and then put the FM filter into the KRX3? > >> > > > >> > > I'm hoping that I can then use the MainRX for broad frequency > >> > > coverage and AM broadcast receive. Then if I ever > want to do FM > >> > > work I simply have to use the sub receiver to do so. Will TX > >> > > through the FM filter work with it in the sub RX... To > >> the best of > >> > > my knowledge it appears that I can set the rig up in > this fashion > >> > > but that doesn't always mean it will work how I expect it to. > >> > > > >> > > Am I all wet here? > >> > > > >> > > Thanks > >> > > > >> > > ~Brett > >> > > > >> > > ______________________________________________________________ > >> > > Elecraft mailing list > >> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> > > Help: http://mailman.qth.net/mmfaq.htm > >> > > Post: mailto:[email protected] > >> > > > >> > > 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:[email protected] > >> > > >> > 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:[email protected] > >> > >> 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:[email protected] > > > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
