I spent some time last night playing with various filter settings via the K3 utility. What I found is that the 250 8p filter in the main required no boost to maintain signal level as I dialed down the bandwidth and engaged it. The suspect one in the subrx required 6db of boost.
Has anyone else seen this level of boost required? With the subrx bandwidth increased to be just above its 250hz8p filter the receiver comes alive nicely. I'll open up the K3 this weekend and do a filter inspection to see if there is some crud on the pins and try a filter swap to the main just to verify my suspicion of a bad filter. I may have to order another... jim ab3cv On Wed, Mar 27, 2013 at 12:55 AM, Vic K2VCO <k2vco....@gmail.com> wrote: > Make sure the filter gain compensation is set properly for the 250 Hz > filter. The easiest way to do it is from the filter configuration screen of > the K3 utility. > > > On 3/26/2013 5:44 PM, Jim Miller wrote: > >> Just used the K3 utility to disable the 250 8p on the sub and the audio >> now >> is balanced regardless of sub bandwidth. Of course the noise level changes >> but no imbalance with strong or weak sigs between the two. >> >> Now to figure out if it's the socket or the filter at fault. >> >> jim >> >> On Tue, Mar 26, 2013 at 8:22 PM, Jim Miller <j...@jtmiller.com> wrote: >> >> I think I've figured out why my subrx seems to be much less sensitive >>> than >>> the main. I was playing around with the bandwidth control today while >>> having the VFOs linked. >>> >>> I have the same filter setup in main and sub, a 2.8K and a 250hz, both 8 >>> pole. I have both main and sub set to cut to the 250 at 350hz. I do most >>> of >>> my Dx activity with the BW set to 350 so engaging the 250hz filter. >>> >>> What I noticed is that although the sub is much less sensitive than the >>> main with the 250 engaged it is just fine just above where the filter >>> kicks >>> in. >>> >>> This tells me that something is wrong with the filter or the socket it is >>> in. The balance control has to be set past 3 oclock to even out the >>> signals >>> with the 250 engaged in the sub. The balance is just fine however when >>> that >>> filter isn't engaged. >>> >>> I'm going to try moving the filter to another socket in the sub to see >>> what effect that has. >>> >>> I can also try swapping the 250 between the sub and the main to see if >>> the >>> loss of sensitivity tracks the filter placement. >>> >>> Any other ideas? >>> >>> It could be a bad filter. I don't think the filters should be that >>> different in loss when in spec. >>> >>> jim >>> >>> ______________________________**______________________________**__ >> Elecraft mailing list >> Home: >> http://mailman.qth.net/**mailman/listinfo/elecraft<http://mailman.qth.net/mailman/listinfo/elecraft> >> Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm> >> Post: mailto:elecr...@mailman.qth.**net <Elecraft@mailman.qth.net> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > > -- > Vic, K2VCO > Fresno CA > http://www.qsl.net/k2vco/ > > ______________________________**______________________________**__ > Elecraft mailing list > Home: > http://mailman.qth.net/**mailman/listinfo/elecraft<http://mailman.qth.net/mailman/listinfo/elecraft> > Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm> > Post: mailto:elecr...@mailman.qth.**net <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
