Re: [Elecraft] K3 AM reception
Re the AM quality question I can't detect any clicking or other distortion but then there are no high quality AM BC transmissions round here - they're messed up either with selective fading or because the transmission comes from more than one location on the same frequency. The noise in between a string of dots is due to AGC PLS=nor. Setting AGC PLS = off cures it. 73 Graham -- From: Wes Stewart n...@yahoo.com [snip] Now it might be argued that these artifacts are at such a low level they would not be audible as distortion. Maybe, but they represent essentially a static situation. When listening to a string of dots sent with my '870 the difference between fast and slow AGC is clearly audible. When the signal is S4 or 5, with fast AGC there is garbage that essentially sounds like an increased noise level. A simple test such as tuning in WWV and listening to the voice ID and hearing the audio distortion and syllabic clicking disappear when simply turning the AGC off and turning the RG gain down appropriately indicates a real problem. If there are K3s out there that don't do this, then I want one of them. Wes N7WS __ 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
Re: [Elecraft] K3 AM reception
I haven't noticed any clicking either. As to selective fading, it sure would be a good thing if the AM sync detector were high on the priority list. I hate it that my manual continues to be so out of touch. Or maybe I'm the only K3 owner who is not a CW Contester or operator of PSK31/RATT/digi mode of your choice :-) Grant/NQ5T On Feb 3, 2009, at 11:56 AM, Graham Kimbell (G3TCT) wrote: Re the AM quality question I can't detect any clicking or other distortion but then there are no high quality AM BC transmissions round here - they're messed up either with selective fading or because the transmission comes from more than one location on the same frequency. __ 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
Re: [Elecraft] K3 AM reception
I am using an unmodified #705 K3 with the AM filter only. Using amplified computer speakers with RF filtering. The AM BCB/SW sounds as good or better than any I have around the house including an old Hallicrafter SX-100 and two Yaesu's. Better than car AM also. Maybe the problem on some units could be related to power supply hum or switch mode PS hash?? good luck Gill W4RYW -- View this message in context: http://n2.nabble.com/K3-AM-reception-tp2254009p2266791.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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
Re: [Elecraft] K3 AM reception
Wes Stewart wrote: Following are links to plots that demonstrate some of the fun I'm having. The first two are taken using Spectrum Lab to look at the Line Out audio signal from the K3. The input signal is from a homebrew 28.7 MHz crystal oscillator/buffer with about a -70 dBm output level. For these particular plots the K3 mode was set to LSB, although I saw, but didn’t record the same issue on CW. The beat note is 450 Hz. The Line Out is run into the microphone input of the built-in sound card in my Lenovo T400 laptop. Care was taken to insure that the sound card wasn't being overdriven. Have you done the AF Stage Upgrade? While the K3's speaker and line outputs meet the original K3 distortion specifications at their intended levels of operation, we've found that further improvement is possible, especially at higher volume levels, with minor component changes. Low level distortion products can be further reduced at both outputs. These changes are being incorporated into new K3s. http://www.elecraft.com/K3/mods/K3_AF_Stage_Upgrade_Instructions_Rev_B.pdf Do you notice the same distortion when using the headphone output? I have good ears and a lot of experience on CW. All 3 of the K3s I've had have excellent audio fidelity when using a good set of headphones (headphone output has apparently never had this problem). This also sounds very similar to UR5LAM's issue posted about some 3 months ago, which I believe resulted in the above mod. 73, Bill -- View this message in context: http://n2.nabble.com/K3-AM-reception-tp2254009p2259061.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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
Re: [Elecraft] K3 AM reception
Wes Stewart wrote: For the second plot, *nothing* has been changed except the AGC button was toggled to Fast. http://k6mhe.com/n7ws/K3_AGC_Fast.jpg Very interesting - looks like an 80hz signal from somewhere is mixing with the fundamental. 73, Barry N1EU -- View this message in context: http://n2.nabble.com/K3-AM-reception-tp2254009p2259143.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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
Re: [Elecraft] K3 AM reception
Hi Bill, Supposedly my S/N has the mods already. Nevertheless, I don't use the line output for anything normally and speakers are for listening to music. I won't be wasting my time looking for the problem if I wasn't actually hearing it too in my good quality headphones. Regards, Wes --- On Mon, 2/2/09, Bill W4ZV btipp...@alum.mit.edu wrote: From: Bill W4ZV btipp...@alum.mit.edu Subject: Re: [Elecraft] K3 AM reception To: elecraft@mailman.qth.net Date: Monday, February 2, 2009, 10:01 AM Wes Stewart wrote: Following are links to plots that demonstrate some of the fun I'm having. The first two are taken using Spectrum Lab to look at the Line Out audio signal from the K3. The input signal is from a homebrew 28.7 MHz crystal oscillator/buffer with about a -70 dBm output level. For these particular plots the K3 mode was set to LSB, although I saw, but didn’t record the same issue on CW. The beat note is 450 Hz. The Line Out is run into the microphone input of the built-in sound card in my Lenovo T400 laptop. Care was taken to insure that the sound card wasn't being overdriven. Have you done the AF Stage Upgrade? While the K3's speaker and line outputs meet the original K3 distortion specifications at their intended levels of operation, we've found that further improvement is possible, especially at higher volume levels, with minor component changes. Low level distortion products can be further reduced at both outputs. These changes are being incorporated into new K3s. http://www.elecraft.com/K3/mods/K3_AF_Stage_Upgrade_Instructions_Rev_B.pdf Do you notice the same distortion when using the headphone output? I have good ears and a lot of experience on CW. All 3 of the K3s I've had have excellent audio fidelity when using a good set of headphones (headphone output has apparently never had this problem). This also sounds very similar to UR5LAM's issue posted about some 3 months ago, which I believe resulted in the above mod. 73, Bill -- View this message in context: http://n2.nabble.com/K3-AM-reception-tp2254009p2259061.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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 __ 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
Re: [Elecraft] K3 AM reception
--- On Sun, 2/1/09, Jim Garland 4cx2...@muohio.edu wrote: I've been reading a thread on another email reflector about the K3's audio response on AM. One of the reflector participants is a serious SWBC listener and is very dissatisfied with his K3's AM audio. He has pointed out a few things about the K3 AM response which puzzle me. Here they are: My K3 sounds the same as others I've heard which I consider to be absolutely terrible when using an external speaker and beyond absolutely terrible when using the internal speaker! The 6KHz roofing filter in the K3 will provide an audio bandwidth of up to 3KHz and the FM 13KHz roofing filter will enable the DSP to provide the user with an audio bandwidth of approximately 4.5KHz I've been told by Elecraft. He also says that Re the bandwidth, a short time ago Elecraft made a mod to the firmware so that audio bandwidth and not IF bandwidth was displayed on the K3's screen. If you're seeing 5KHz and you don't have FM filter installed then it sounds like yet another bug. His particular complaint is audio clicks on AM when hard consonants (Ts, Ks, etc) are spoken, a problem that he says has been confirmed by other users. He has installed all the audio mods in his radio, but they didn't fix the problem. This was all news to me. I've not used my K3 extensively on AM, and maybe my ears aren't as sensitive as his, but I've not noticed any problem. I have the 6 kHz roofing filter in my radio, and the DSP BW goes up to 5 kHz, which he says is a bug, and that the actual BW is only 3kHz. So my questions are: (1) Is audio distortion on AM a known problem with the K3? (2) What does the LCD BW actually read? Is it an IF BW, an audio BW, or what, and does the displayed BW actually corresond to reality? Tnx, Jim W8ZR Answer to (1). Yes. At least in my K3 and it's not limited to AM. I've been trying to determine the cause of this for the month that I've been using it. I didn't really want to pay $2,200 for another science project and would much rather be working on antennas though. My experiments now suggest the problem (or at least one of the problems) is AGC related. Following are links to plots that demonstrate some of the fun I'm having. The first two are taken using Spectrum Lab to look at the Line Out audio signal from the K3. The input signal is from a homebrew 28.7 MHz crystal oscillator/buffer with about a -70 dBm output level. For these particular plots the K3 mode was set to LSB, although I saw, but didn’t record the same issue on CW. The beat note is 450 Hz. The Line Out is run into the microphone input of the built-in sound card in my Lenovo T400 laptop. Care was taken to insure that the sound card wasn't being overdriven. The K3 DSP bandwidth is set to default values, as are the AGC parameters and the crystal filter is a 2.8 KHz, 8-pole. (Note: all of these adjustments affect the results. Trying to categorize them all would drive one crazy. If you don’t like the answer, turn a knob.) The first plot is with the AGC set to Slow. http://k6mhe.com/n7ws/K3_AGC_Slow.jpg For the second plot, *nothing* has been changed except the AGC button was toggled to Fast. http://k6mhe.com/n7ws/K3_AGC_Fast.jpg For a sanity check, the third plot is from the aux audio output of my Kenwood TS-870S while it is tuned to the same signal as the K3. http://k6mhe.com/n7ws/TS_870.jpg Now it might be argued that these artifacts are at such a low level they would not be audible as distortion. Maybe, but they represent essentially a static situation. When listening to a string of dots sent with my '870 the difference between fast and slow AGC is clearly audible. When the signal is S4 or 5, with fast AGC there is garbage that essentially sounds like an increased noise level. A simple test such as tuning in WWV and listening to the voice ID and hearing the audio distortion and syllabic clicking disappear when simply turning the AGC off and turning the RG gain down appropriately indicates a real problem. If there are K3s out there that don't do this, then I want one of them. Wes N7WS __ 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
Re: [Elecraft] K3 AM reception
Jim, My K3's receiver also works and sounds great on AM. I have probably spent more time listening to AM broadcast with it than anything else thus far. I use my old Yaesu SP-8 external speaker and it sounds very good to me - and I have tried cranking it up pretty loud, and I hear no distortion at all - certainly none of the clicking. I have tried all AGC options also - no difference. I have the 6 kHz filter. Given the comments I saw here before I got my K3, and knowing that casual AM bcst listening is something I do pretty regularly, I was a bit worried about the K3's performance on AM. 73, Bob W5OV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Garland Sent: Sunday, February 01, 2009 9:08 AM To: elecraft@mailman.qth.net Subject: [Elecraft] K3 AM reception I've been reading a thread on another email reflector about the K3's audio response on AM. One of the reflector participants is a serious SWBC listener and is very dissatisfied with his K3's AM audio. He has pointed out a few things about the K3 AM response which puzzle me. Here they are: My K3 sounds the same as others I've heard which I consider to be absolutely terrible when using an external speaker and beyond absolutely terrible when using the internal speaker! The 6KHz roofing filter in the K3 will provide an audio bandwidth of up to 3KHz and the FM 13KHz roofing filter will enable the DSP to provide the user with an audio bandwidth of approximately 4.5KHz I've been told by Elecraft. He also says that Re the bandwidth, a short time ago Elecraft made a mod to the firmware so that audio bandwidth and not IF bandwidth was displayed on the K3's screen. If you're seeing 5KHz and you don't have FM filter installed then it sounds like yet another bug. His particular complaint is audio clicks on AM when hard consonants (Ts, Ks, etc) are spoken, a problem that he says has been confirmed by other users. He has installed all the audio mods in his radio, but they didn't fix the problem. This was all news to me. I've not used my K3 extensively on AM, and maybe my ears aren't as sensitive as his, but I've not noticed any problem. I have the 6 kHz roofing filter in my radio, and the DSP BW goes up to 5 kHz, which he says is a bug, and that the actual BW is only 3kHz. So my questions are: (1) Is audio distortion on AM a known problem with the K3? (2) What does the LCD BW actually read? Is it an IF BW, an audio BW, or what, and does the displayed BW actually corresond to reality? Tnx, Jim W8ZR __ 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 __ 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
Re: [Elecraft] K3 AM reception
Jim, He also says that Re the bandwidth, a short time ago Elecraft made a mod to the firmware so that audio bandwidth and not IF bandwidth was displayed on the K3's screen. If you're seeing 5KHz and you don't have FM filter installed then it sounds like yet another bug. This isn't a bug. The DSP bandwidth is simply wider than the IF filter. In practice the user will see audio out to 4 KHz or so at a reduced level following the filter skirts. (2) What does the LCD BW actually read? Is it an IF BW, an audio BW, or what, and does the displayed BW actually corresond to reality? For wide modes the best way to display the bandwidth is LO/HI. Those are the numbers that correspond to the real world. If you are looking at FC/BW, the BW number will be 2 * (HI-FC). Where FC is less than HI/2, BW will typically be overstated. In AM for example, NORM is BW=5.00 and FC=1.50. If you toggle to the LO/HI display you will find it showing LO=0.00 and HI=4.00. Most users would consider that to be BW=4.00. It is most convenient to consider that (other than in CW) the the audio DSP limits are FC=2.20, HI=4.20. 73, ... Joe, W4TV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Garland Sent: Sunday, February 01, 2009 10:08 AM To: elecraft@mailman.qth.net Subject: [Elecraft] K3 AM reception I've been reading a thread on another email reflector about the K3's audio response on AM. One of the reflector participants is a serious SWBC listener and is very dissatisfied with his K3's AM audio. He has pointed out a few things about the K3 AM response which puzzle me. Here they are: My K3 sounds the same as others I've heard which I consider to be absolutely terrible when using an external speaker and beyond absolutely terrible when using the internal speaker! The 6KHz roofing filter in the K3 will provide an audio bandwidth of up to 3KHz and the FM 13KHz roofing filter will enable the DSP to provide the user with an audio bandwidth of approximately 4.5KHz I've been told by Elecraft. He also says that Re the bandwidth, a short time ago Elecraft made a mod to the firmware so that audio bandwidth and not IF bandwidth was displayed on the K3's screen. If you're seeing 5KHz and you don't have FM filter installed then it sounds like yet another bug. His particular complaint is audio clicks on AM when hard consonants (Ts, Ks, etc) are spoken, a problem that he says has been confirmed by other users. He has installed all the audio mods in his radio, but they didn't fix the problem. This was all news to me. I've not used my K3 extensively on AM, and maybe my ears aren't as sensitive as his, but I've not noticed any problem. I have the 6 kHz roofing filter in my radio, and the DSP BW goes up to 5 kHz, which he says is a bug, and that the actual BW is only 3kHz. So my questions are: (1) Is audio distortion on AM a known problem with the K3? (2) What does the LCD BW actually read? Is it an IF BW, an audio BW, or what, and does the displayed BW actually corresond to reality? Tnx, Jim W8ZR __ 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 __ 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
Re: [Elecraft] K3 AM reception
My K3 sounds great on BCB/SW AM reception - in fact I'm listening to it right now. I have the FM filter and the DSP BW cranked up to the maximum. It reads 10 KHz, but I am using far from the latest version of firmware. I'm using the West Mountain Comspkrs on the rear speaker jack. They are powered speakers, but work just fine with the audio level on the speaker output. This allows me to control the volume with the K3 audio gain and the stereo output nicely showcases the AFX effects. I can highly recommend these speakers - quite a value for the $ and supposedly shielded for RF. I have a single Fostex 6301B connected to the line out for a center channel. This allows for a variable insertion of some additional high end to brighten up the sound if desired. The overall effect is quite pleasing. I also use it sometimes for casual operating, but always phones for contesting. The only popping/clicking issue I know of is if you have the noise blanker or noise reduction engaged with a strong (20 over 9 or above) signal. Keep them off. 73 ... Craig AC0DS __ 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
Re: [Elecraft] K3: AM Reception
Seriously, we'll investigate further to see what can be done about this. But in the meantime, please understand that only huge signals exhibit the symptom, and then only if you are not tuned to the station's carrier frequency. 73, Lyle KK7P Wow, Lyle! It sounds like with a little more work you'll nearly have a synchronous detector for us. Dave W5DHM ___ 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
