I agree that corresponding with the end of the ALC bracket makes sense. I remember looking at the pictures of the radio after it was mentioned that the 6th bar was overdrive and I was thinking it odd that the overdrive point didn't correspond to the end of the ALC brackets. My Kenwood has a line that tells one where the ALC kicks in. It just seems like that type of operation makes intuitive sense where as the 5 bars thing is something that one would have to read the manual/reflector to know.
On Sun, 2008-04-13 at 21:56 -0400, Joe Subich, W4TV wrote: > Andy, > > > Here is what happens: For phone contesting, I my software > > CQPWIN, which plays wav files for DVK usage (as do other > > programs). I run the output in such a way that when the dvk > > is playing, the mic is shut off, but the audio from the computer > > goes into the mic connector of the radio. As soon as it stops > > playing, it disconnects the computer and reconnects the > > microphone. I run it from the computer into a W2IHY iBox for > > isolation, and the output to the radio. The Mic is a Heil > > pro-set. > > > > With the K3, the messages play fine, but after one finishes, > > if I use the mic, the radio starts out at lower power and takes > > 2-4 seconds to build back up to high power. This is the same > > whether using the front or rear input and whether using high or > > low gain. > > After working in this quite a bit over the weekend the problem > is related to the K3 "microphone AGC." It appears that levels > from the microphone and DVK must be extremely well balanced - > much more closely balanced than with any other radio or the > stronger input will cause the microphone AGC to reduce the > mic gain and the weaker input will be much weaker. The 2-4 > second delay seems to be related to an extremely long ACG time > constant (probably intended to prevent the ACG from acting like > a clipper). > > The problem is made worse - at least in my case - because the > ALC indicator provides only 5 very small, difficult to see, > bars for adjustment and the "steps" are rather course (6 dB > per division). This means that the maximum "spread" between > the two inputs can be almost 12 dB (!) even when the display > only shows a slight flicker between the two adjacent bars > (e.g., the mic is barely triggering the 5th bar and the DVK > is hitting the sixth bar "hard"). > > After some thought there are several ways (a combination of > all is best) to help the situation: > > 1) reduce the time constant (AGC "hang") to about .5 second > and "dump" any gain reduction when the PTT is released. > > 2) Use more of the "ALC" display to get better resolution. > There are 12 "bars" in that part of the display but only > six are used (with the sixth indicating overdrive). At > least expand the "good" range to seven (or eight) bars > to coincide with the right edge of the ALC bracket. > > 3) Make the ALC display response logarithmic (like a VU > meter). Instead of 5 x 6 dB or 30 dB total ... the same > total range could be displayed with the first bar = -20 dB, > the second = -10 dB, the third = -7 dB, the fourth = -5 dB, > the fifth = -3 dB, the sixth -1 dB, the seventh = "0 dB", > the eighth +1 dB, the ninth +3 dB and the 10th +6 dB. > Setting/matching levels would be MUCH easier. It's no > accident that professional recording and broadcasting have > used similar scales for decades. > > 4) Give the ALC meter a dual mode display - showing both short > duration "peak" and average (the current ALC) would help. > Alternatively, any "peak hold" dot above the ALC region > could show gain reduction by the mic AGC (and warn about > overdriving the input). > > 5) Provide a "set-up mode" that disables mic AGC - this > will allow balancing sources (either FP/RP/Line or > multiple inputs on an external mixer) without chasing > the effects of the mic AGC. > > I understand there has been some work on the mic AGC in the > firmware currently in test and that may help. However, this > area needs to be more "user friendly." As it is, I can see > significant issues when using the K3 in a multi-operator > setting where the relative levels need to be reset completely > for every operator change! > > 73, > > ... Joe, W4TV > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Andy Faber > > Sent: Monday, April 07, 2008 12:08 AM > > To: [EMAIL PROTECTED]; wayne burdick > > Cc: elecraft@mailman.qth.net > > Subject: [Elecraft] Audio problem in WPX SSB > > > > > > Wayne, > > A peculiar audio situation arose using my K3 in Aruba in > > WPX SSB. It > > works the same way at home, and isn't a problem I've ever had > > with any of > > many other radios that I've used in the same contest configuration. > > > > Here is what happens: For phone contesting, I my software > > CQPWIN, which > > plays wav files for DVK usage (as do other programs). I run > > the output in > > such a way that when the dvk is playing, the mic is shut off, > > but the audio > > from the computer goes into the mic connector of the radio. > > As soon as it > > stops playing, it disconnects the computer and reconnects the > > microphone. > > I run it from the computer into a W2IHY iBox for isolation, > > and the output > > to the radio. The Mic is a Heil pro-set. > > > > With the K3, the messages play fine, but after one > > finishes, if I use the > > mic, the radio starts out at lower power and takes 2-4 > > seconds to build back > > up to high power. This is the same whether using the front > > or rear input > > and whether using high or low gain. Also, the W2IHY box has > > to be turned up > > to a level that normally would overdrive other radios. > > > > I tried not using the W2IHY box (ie, running the audio > > straight from > > either my laptop or my desktop to the radio) with the same > > result. It also > > doesn't matter if the radio is using PTT or VOX, or whether > > it just remains > > in transmit. > > > > These seems like a some kind of odd impedance issue, but, > > as I said, it's > > one that has never shown up with Icom-Yaesu or Kenwood radios. > > > > Any ideas? I'm using 1.78/1.58 firmware, and the radio was > > just back to > > you for Rene to do hardware mods (serial number 76). In all > > other respects, > > I loved it in the contest. > > > > 73, Andy, AE6Y > > > > > > _______________________________________________ > > Elecraft mailing list > > Post to: Elecraft@mailman.qth.net > > 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: Elecraft@mailman.qth.net > 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: Elecraft@mailman.qth.net 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
