+++++++++++++++++++ See also KAF2 Notes --- This one is a continuation of it. ++++++++++++++++ Date: Tue, 01 Jan 2002 21:09:56 -0800 From: Wayne Burdick Organization: Elecraft To: Francis Belliveau CC: K2 List , Gary Surrency , scott at elecraft.com Subject: [Elecraft] Re: RTC Question (February 31st) Francis Belliveau wrote: > While I was trying to set the date, the display > frequently changed to F0.91; I'm wondering what that meant? Hi Fran, You just discovered an obscure feature of the KAF2 firmware that I neglected to document in the KAF2 manual: if you set the date to February 31st (any year), the RTC display will show the KAF2 micrcontroller's firmware revision. (We picked this invalid date because we assumed it would never be used during normal date setting, but your RTC chip apparently came up with it somehow.) You saw "F0.91" which means revision 0.91, the current production revision. KAF2 PICs with this revision of firmware may actually be labeled "1.00". I'll add this to the next rev of the KAF2 manual. Thanks, Wayne N6KR ++++++++++++++++++++++ Date: Fri, 08 Feb 2002 16:06:59 +1300 From: Ron ZL1TW To: Elecraft Subject: [Elecraft] KAF2 possible problem. Greetings all, Some time back I installed the KAF2 (Mid Jan), and it worked fine , in fact it still does, but I recently had reason to suspect it caused a wee problem in my radio. I was doing my EMail one morning, and the K2 was set to listen to a local net, when all of a sudden there was quite a loud "POP" and the audio dissapeared. Tuning didn't alter the frequency the display was set to, and I couldn't change bands. I turned the set off and on again...no change. I then turned it off and finished my EMail before trying again......this time the set booted up fine and worked as it should. I popped a note off to Gary to suggest what to look for, and one suggestion of his was to look at the KAF2 and see I had clearance between the bottom of the KAF2 board and the two larger caps under it, on the Control board. I didn't have any, so I removed the KAF2 and the stand off, and placed one of the flatter wave washers over the threaded end of the stand off and reinstalled it, and the filter again. This time I had a small but distinct gap between the components. Now while this might be "stab in the dark" problem solving, I had reason to believe a short may well have happened there when I looked at the clock display. It showed the 01.01.01 display you get when you first boot the clock into life. Subsequent resetting of the clock has been successful,and there have been no further mysterious outages. There may well have been a posting on this reflector in the past regarding making sure there is indeed clearance under the KAF2 , my apologies if I am re-writing history, but I guess it doesn't hurt to repeat these traps once in a while for the up and coming constructors. Cheers........Ron ZL1TW +++++++++++++++++++++++ Date: Sat, 23 Feb 2002 11:41:54 -0600 To: "Jason Hissong" , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] K2 Audio Filter Jason: >Having fun playing with the K2. No QSO's yet because I have not gone to >Radio Shack to get an adaptor for my straight key to the K2. Anyways, >something I noticed, when I use the Audio Filter, it seems that the volume >is attentuated a great deal. I take it that this is normal? If the KAF2 is properly aligned, to your SIDETONE frequency, you SHOULD norice a significant decrease in BACKGROUND noise, but NOT the signal you are receiving (IF it is properly zero beat to the sidetone). >Also, anyway to keep the noise from the monitor down to a minumum? I >notice that this monitor gives off a lot of noise. Sometimes adding a couple (few) lossy ferrite cores around the power and data cable will help. Other than that, either turning it OFF (clearly UNacceptable), moving your end-fed antenna farther from the rig, or using a coax-fed antenna outside. Tom Hammond N0SS +++++++++++++++++++++ From: "K7FD N7SG" To: jhisson1 at columbus.rr.com, elecraft at mailman.qth.net Subject: Re: [Elecraft] K2 Audio Filter Date: Sat, 23 Feb 2002 10:01:59 -0800 My monitor was generating a very nasty noise, too. Ferrite cores (the good kind, from Amidon) were a gallant try but didn't do the job. What did work was grounding the monitor cable. That completely eliminated the noise... Re: KAF2, realign it. When working properly, the audio filter will actually 'showcase' a signal making copy much easier. 73 John K7FD, K2/586 >From: "Jason Hissong" >Also, anyway to keep the noise from the monitor down to a minumum? I >notice >that this monitor gives off a lot of noise. ++++++++++++++++ From: "Jason Hissong" To: Subject: Re: [Elecraft] K2 Audio Filter Date: Sat, 23 Feb 2002 13:05:07 -0500 It appears that the sidetone frequency is pretty low. I am used to a higher tone in CW than what this is set to. Once I found out where the "center" was (which is fairly low) I then tried the AF and there was no volume drop. Looks like I just have to adjust the side tone to a higher pitch... I also noticed that the pitch changes a little when I go between some of the filters, not alot, but noticable. (Of course being a Musician, it drives me nuts!! hehehe) Thanks Jason ++++++++++++++++++++ From: "Robert Fanfant" To: "ZOOM" , Subject: Re: [Elecraft] K2 - Low audio with Audio Filter installed Date: Sat, 20 Apr 2002 08:42:02 -0700 Problem solved. After going through the filter alignment process, my audio came right. up. I had incorrectly assumed I had done something wrong as my audio level was barely audible with the volume control at the 5 o'clock position. But thanks to both yours and Tom's (N0SS) input, I forged ahead and am glad to say that it was just a filter alignment issue. -rob N7QT ++++++++++++++++ Date: Mon, 13 Jan 2003 07:20:13 -0500 From: "Dale M. Boresz" To: elecraft at mailman.qth.net Subject: Re: [Elecraft] KAF2 Question.... I have a K2 with the KAF2 filter, and I rarely turn it off, other than when I'm using the K2 on SSB which is very rare. The filter is a big help in a couple of ways: - When set up properly (so that the center frequency of the filter is the same as your BFO frequency - mine is 600 Hz), it creates a slight peaking situation which assists one in placing the received signal at the same pitch as the BFO frequency. The audible signal level noticeably peaks out as you tune it through the filter passband, and if you stop on that peak, you'll end up within a few tens of cycles of the BFO frequency. - The filter also significantly helps to reduce non-signal band noise, which in my opinion makes copying much easier on the ears, and much less fatiguing. - The added selectivity of the filter helps a lot in crowded band conditions. It's effect is not the same as switching to a tighter xtal filter bandwidth; rather, it simply reduces some of the clutter surrounding the signal of interest without changing the actual I.F. passband. - You can configure the filter such that both filters are either simultaneously on, or both are simultaneously off, OR - so that just the first filter can be run, or the combination of the two can be run, or they can both be off. I'd suggest you select the second configuration; cascading the two filters is rarely necessary, and creates a bit too much peaking for just casual tuning around the bands, although it can be helpful in copying very weak signals. It's nice to have the ability to use one, both, or neither filter. - I have had situations where the station I was trying to copy not only was not registering on the S - meter, but was pretty much at the noise level. I could hear keying, but couldn't actually copy anything. By switching in *both* filters and carefully tuning that station so that it lands at the peak of both filters, the station became copyable. So there you have it - I wouldn't be without the filter. Oh yeah, the realtime clock is a nice touch too, but in my opinion it's the filters that really provide the bang for the buck. 73, Dale WA8SRA > > > My question is, being the K2 has the VBW filter already, how much more > does the KAF2 actually help with CW operation? I have never operated > a rig with the combination of a tight VBW filter and an audio filter > of this type, so I do not know what the combination will do for me. > The info on the website says it is especially useful on quiet bands, > but how does it perform when the bands are quite crowded, i.e. ARRL SS > ? > +++++++++++++++++++ From: "Bob - AG5Q" To: , Subject: Re: [Elecraft] RE: Speaker for K2 - Low audio Date: Mon, 3 Feb 2003 11:20:32 -0600 Hi Bruce, If you have the KAF2 Audio Filter, you can increase the audio by changing R9 to a larger value. Something in the range of 20K to 33K will help. 73/ Bob - AG5Q +++++++++++++++++++ From: "Lyle Johnson" To: "Don Lerche" , Subject: RE: [Elecraft] KAF2 Connections to Control Board Date: Mon, 3 Mar 2003 08:04:41 -0800 Hello Don! > ... I have a question regarding the connections between the KAF2 and the > Control Board. When the standoff is fitted between the boards, > this prevents > the connectors J1/P1 and J2/P2 from mating fully, and there is between 1mm > and 2mm of the pins showing. Is this normal... Yes, mine has the same characteristic. 73, Lyle KK7P +++++++++++++++++++++