[Elecraft] Beware! (Learn by doing?) :-)))
Gentlemen, A few days ago I was messing around with the K3 (as usual) and having set the AF gain control at about 11 O'clock with the AGC set for fast I wondered what would the audio results be if I switched OFF the AGC with that particular setting. BIG MISTAKE! When the AGC is OFF the resulting audio thru the speaker almost blew out my left-eardrum!!! In other rigs that was never a concern because it would never happen (PERIOD!) Why such a HUGE difference in audio between on/off states of (AGC) in the K3??? A K3 Greenhorn, Jim/nn6ee S/N 2406 ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
Jim, We old-timers learned about that long ago - do NOT turn AGC off without first turning the gain down! As for other receivers not doing that - many do not allow the AGC to be turned off at all, they have only AGC Fast and Slow available on a button - if one wants to reduce the AGC action, reducing the RF gain is about the only way to accomplish it. At least on the Yaesu FT900 and FT847 I know that is true, other transceivers may allow AGC off, but those I have encountered recently, except for the K2 and K3, do not. 73, Don W3FPR JIM DAVIS wrote: Gentlemen, A few days ago I was messing around with the K3 (as usual) and having set the AF gain control at about 11 O'clock with the AGC set for fast I wondered what would the audio results be if I switched OFF the AGC with that particular setting. BIG MISTAKE! When the AGC is OFF the resulting audio thru the speaker almost blew out my left-eardrum!!! In other rigs that was never a concern because it would never happen (PERIOD!) Why such a HUGE difference in audio between on/off states of (AGC) in the K3??? A K3 Greenhorn, Jim/nn6ee S/N 2406 ___ 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 No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.10.14/1918 - Release Date: 1/27/2009 7:26 AM ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
On Tue, 27 Jan 2009 15:15:49 -0500 Don Wilhelm w3...@embarqmail.com wrote: Jim, We old-timers learned about that long ago - do NOT turn AGC off without first turning the gain down! As for other receivers not doing that - many do not allow the AGC to be turned off at all, they have only AGC Fast and Slow available on a button - if one wants to reduce the AGC action, reducing the RF gain is about the only way to accomplish it. At least on the Yaesu FT900 and FT847 I know that is true, other transceivers may allow AGC off, but those I have encountered recently, except for the K2 and K3, do not. 73, Don W3FPR JIM DAVIS wrote: Gentlemen, A few days ago I was messing around with the K3 (as usual) and having set the AF gain control at about 11 O'clock with the AGC set for fast I wondered what would the audio results be if I switched OFF the AGC with that particular setting. BIG MISTAKE! When the AGC is OFF the resulting audio thru the speaker almost blew out my left-eardrum!!! In other rigs that was never a concern because it would never happen (PERIOD!) Why such a HUGE difference in audio between on/off states of (AGC) in the K3??? A K3 Greenhorn, Jim/nn6ee S/N 2406 *** Don M'Boy, You live a sheltered life! The TenTec Orion allowed the user to shutoff the AGC @ will and the resulting big difference in audio was NOT THERE! At best maybe a s-unit or so but nothing approaching what I had described earlier. But it was a great learning experience (sort of like first-marriages!!! :-))) ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
That has happened to me, too. I think it's because the AF amp has a lot of headroom, especially if config af gain = HI. There is an AF limiter setting: config tech md = on config af lim = 20 (adjust to personal preference) I operated my old TS-850 with agc off on cw, but can't really do it with the K3 without riding the rf or af gain control. Loud signals either hurt my ears, or hit the limiter, making them sound like mush. I operate the K3 on cw with fast agc, config agc slp = 0, config agc thr = 8. That seems to work well for me. Dave Hachadorian, K6LL Yuma, AZ - Original Message - From: JIM DAVIS nn...@astound.net To: elecraft@mailman.qth.net Sent: Tuesday, January 27, 2009 7:52 PM Subject: [Elecraft] Beware! (Learn by doing?) :-))) Gentlemen, A few days ago I was messing around with the K3 (as usual) and having set the AF gain control at about 11 O'clock with the AGC set for fast I wondered what would the audio results be if I switched OFF the AGC with that particular setting. BIG MISTAKE! When the AGC is OFF the resulting audio thru the speaker almost blew out my left-eardrum!!! In other rigs that was never a concern because it would never happen (PERIOD!) Why such a HUGE difference in audio between on/off states of (AGC) in the K3??? A K3 Greenhorn, Jim/nn6ee S/N 2406 ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
- Original Message - From: Don Wilhelm w3...@embarqmail.com ...other transceivers may allow AGC off, but those I have encountered recently, except for the K2 and K3, do not. TS-480SAT, no real change in audio level when AGC is off. Simon Brown, HB9DRV www.ham-radio-deluxe.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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
A few days ago I was messing around with the K3 (as usual) and having set the AF gain control at about 11 O'clock with the AGC set for fast I wondered what would the audio results be if I switched OFF the AGC with that particular setting. BIG MISTAKE! When the AGC is OFF the resulting audio thru the speaker almost blew out my left-eardrum!!! In other rigs that was never a concern because it would never happen (PERIOD!) Why such a HUGE difference in audio between on/off states of (AGC) in the K3??? The K3 AGC can be set for varying threshold and compression, so turning AGC on and off can reveal dramatic differences in signal level. Recent releases of K3 firmware have an audio limiter that can be set to limit audio levels when AGC is OFF. See the firmware release notes or the latest K3 Manual for how to use the CONFIG:AF LIM feature. 73, Lyle KK7P ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
You live a sheltered life! The TenTec Orion allowed the user to shutoff the AGC @ will and the resulting big difference in audio was NOT THERE! At best maybe a s-unit or so but nothing approaching what I had described earlier. But it was a great learning experience (sort of like first-marriages!!! :-))) I don't know how the K3 does it, but you cannot turn off AGC in the Orion. In the Orion, AGC off simply means AGC very very fast. Tune in a nice loud station with AGC on the R-390, and then flip it off. Best if you you are listening through headphones through a good amplifier with LOTS of headroom ;) After doing that, you won't be able to tell if you have AGC on or off, or if the receiver is on or off, although it will give you a good excuse to give out a didn't hear you to those verbal honey-do's from the spouse :-) Grant/NQ5T ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
Call me dense, but I'm not understanding why one would expect that turning AGC off would NOT result in a huge jump in AF output. AGC turns down RX gain - a lot. The only time there should be no change in AF output is when the RF input is so low that it hasn't reached the AGC threshold. Maybe other manufactures have coupled AGC on/off with AF attenuation, so if the AGC is off, AF output is automatically reduced by 20 dB or something. For this very reason, I always run with AGC on. Even when I want the rig to act like it's off, I leave it on, set to Fast and then just turn the RF gain down to put my signal of interest down near the point where AGC is doing very little. AGC is still on to protect me in case some big signal QRM or QRN shows up. - Keith N1AS - - K3 711 - -Original Message- The TenTec Orion allowed the user to shutoff the AGC @ will and the resulting big difference in audio was NOT THERE! ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-))) (Grant)
On Tue, 27 Jan 2009 14:43:04 -0600 Grant Youngman n...@tx.rr.com wrote: You live a sheltered life! The TenTec Orion allowed the user to shutoff the AGC @ will and the resulting big difference in audio was NOT THERE! At best maybe a s-unit or so but nothing approaching what I had described earlier. But it was a great learning experience (sort of like first-marriages!!! :-))) I don't know how the K3 does it, but you cannot turn off AGC in the Orion. In the Orion, AGC off simply means AGC very very fast. Tune in a nice loud station with AGC on the R-390, and then flip it off. Best if you you are listening through headphones through a good amplifier with LOTS of headroom ;) After doing that, you won't be able to tell if you have AGC on or off, or if the receiver is on or off, although it will give you a good excuse to give out a didn't hear you to those verbal honey-do's from the spouse :-) Grant/NQ5T ___ OH CONTRE Mon'Ami!!! With having used and loved the TT Orion until the K3 came on the scene, the AGC (when-- off) was nothing close to (ultra Fast)! I say that because when also having IT'S NB (hardware-- if. blanker on) there was much less audio-distortion layed onto the resultant audio so as to permit us to HEAR WORK weak signals from our particular location in Concord, Ca. Ca. where the noise can be as high as 10db/S-9 average (especially during the dry/warm months of the year! Your hearing characteristics are obviously a heck of alot different than mine are! Jim/nn6ee S/N 2406 ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-))) (Grant)
OH CONTRE Mon'Ami!!! With having used and loved the TT Orion until the K3 came on the scene, the AGC (when-- off) was nothing close to (ultra Fast)! I We should take this off-list (if there's some reason to continue), but having also been the owner of 2 Orions and an Orion II, I believe that is the way AGC OFF was implemented. As I recall, it had an extremely high decay rate of 1000dB/sec , but nonetheless was still technically on. Perhaps fast was a bad choice of terms to relate to decay rate. in any case, it appears the K3 may work a bit differently. ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
Jim: A few days ago I was messing around with the K3 (as usual) and having set the AF gain control at about 11 O'clock with the AGC set for fast I wondered what would the audio results be if I switched OFF the AGC with that particular setting. BIG MISTAKE! When the AGC is OFF the resulting audio thru the speaker almost blew out my left-eardrum!!! In other rigs that was never a concern because it would never happen (PERIOD!) Why such a HUGE difference in audio between on/off states of (AGC) in the K3??? With all due respect, pal, that's what you get when you turn the Automatic GAIN Control OFF... you no longer have automatic gain 'leveling' and then are completely dependent upon MANUALLY controlling the AF GAIN! However, there IS a setting in the K3 CONFIG menu [AF LIM] which will allow you to limit the amount of output when you turn the AGC off. Hope this helps, 73, Tom HammondN0SS ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
Simon, I certainly don't doubt your word, but I wonder how the TS-480SAT does that - it must reduce the gain somehow. I have been using and building receivers since the mid 1950s and in all cases, turning off the AGC will increase the audio in the receiver - that is true UNLESS there are NO signals at the input strong enough to activate the AGC. The K3 shows no change in the audio level when connected to a dummy load and the AGC is changed from on to off. If there are signals that are being received and the AGC is holding down the gain of the receiver to compensate for those strong signals, then turning off that gain control mechanism would normally result in an increase in the audio level. If it does not, then that receiver used some mechanism other than the AGC to reduce the gain when AGC is off (I would not want my receiver to do that). Normally the increase in audio will depend on just how strong the strongest signal in the passband actually is. 73, Don W3FPR Simon (HB9DRV) wrote: - Original Message - From: Don Wilhelm w3...@embarqmail.com ...other transceivers may allow AGC off, but those I have encountered recently, except for the K2 and K3, do not. TS-480SAT, no real change in audio level when AGC is off. Simon Brown, HB9DRV www.ham-radio-deluxe.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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
The reason radios need such a large dynamic range (one of the K3's selling points) is because there is an enormous difference in signal strength between the weakest and strongest signals on the band. The purpose of the AGC is to reduce that enormous range to a much smaller range that is more tolerable to your ears. The K3 offers a wide range of AGC settings (AGC THR and AGC SLP). There is a very good explanation of the effects of AGC THR and AGC SLP at http://www.cliftonlaboratories.com/elecraft_k3_agc_and_s-meter.htm . When the AGC settings are at their most aggressive (AGC SLP = 15, AGC THR = 2), there is very little difference in audio output level across a very wide range of signal strengths. If your AGC is set to be this aggressive, then turning AGC off will inevitably result in strong signals becoming much louder, possibly by several tens of dB. If your AGC is set to its least aggressive settings (AGC SLP = 0, AGC THR = 8), you will hear a much broader range of signal strength levels with the AGC on, to the extent that you may have to ride the gain controls as you tune from weak to strong signals (especially on a quiet band), but turning AGC off will have a less dramatic impact. If you are observing a more dramatic difference between AGC off and on with the K3 than with another radio, maybe you have the K3's AGC set to be more aggressive than the other radio's. Try decreasing the K3's AGC SLP setting to see if that makes it behave more to your liking. 73, Rich VE3KI K3 #1595 ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
On Jan 27, 2009, at 12:57 PM, Darwin, Keith wrote: For this very reason, I always run with AGC on. Even when I want the rig to act like it's off, I leave it on, set to Fast and then just turn the RF gain down to put my signal of interest down near the point where AGC is doing very little. AGC is still on to protect me in case some big signal QRM or QRN shows up. - Keith N1AS - - K3 711 - I also leave the AGC on but I use minimum slope and maximum threshold. If the AGC is off, the NR doesn't work (but, unlike many rigs, the S Meter does). Otherwise, I would leave the AGC off. Butt it is good to have some sort of limiter to protect my hearing. 73 Rick Dettinger K7MW ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
What's really fun is that you can adjust the AGC slope on the K3 in the config menu. In fact, if you do this while listening to a very strong signal, you can hear exactly what the AGC does to reduce the gain while you are making the adjustment.For this contest, I put in the maximum degree of attenuation, which helped control the strong signals. 73, Andy, AE6Y - Original Message - From: Darwin, Keith keith.dar...@goodrich.com To: Elecraft Reflector elecraft@mailman.qth.net Sent: Tuesday, January 27, 2009 12:57 PM Subject: Re: [Elecraft] Beware! (Learn by doing?) :-))) Call me dense, but I'm not understanding why one would expect that turning AGC off would NOT result in a huge jump in AF output. AGC turns down RX gain - a lot. The only time there should be no change in AF output is when the RF input is so low that it hasn't reached the AGC threshold. Maybe other manufactures have coupled AGC on/off with AF attenuation, so if the AGC is off, AF output is automatically reduced by 20 dB or something. For this very reason, I always run with AGC on. Even when I want the rig to act like it's off, I leave it on, set to Fast and then just turn the RF gain down to put my signal of interest down near the point where AGC is doing very little. AGC is still on to protect me in case some big signal QRM or QRN shows up. - Keith N1AS - - K3 711 - -Original Message- The TenTec Orion allowed the user to shutoff the AGC @ will and the resulting big difference in audio was NOT THERE! ___ 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
Re: [Elecraft] Beware! (Learn by doing?) :-)))
Simon (HB9DRV) wrote: Original Message - From: Don Wilhelm w3...@embarqmail.com ...other transceivers may allow AGC off, but those I have encountered recently, except for the K2 and K3, do not. TS-480SAT, no real change in audio level when AGC is off. Maybe AGC just isn't working on the 480? Just kidding :-) The motto of California State Polytechnic University [Cal Poly], my beloved alma mater is, Learn by Doing. It was never painful. I could do the motto in Latin for you except the T-shirt that has the school seal on it is in the laundry, and I'm not digging into that smelly place until I really have to. In the olden days, one copied CW with the AF gain all the way up and the RF gain for appropriate volume. Had to do with the fixed BFO level in receivers. I don't do that any more, AGC nowadays is sooo good. Still trying to find the best AGC slope in my K3. I like stronger signals to sound louder, but not a whole lot, the dynamic range for my ears is nowhere near what I was born with. 73, Fred K6DGW - Northern California Contest Club - CU in the 2009 Cal QSO Party 3-4 Oct 2009 - www.cqp.org ___ 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
