Re: [Elecraft] Regarding the K3 and high QRN levels
On 2010-07-09 00:02, ve7xf wrote: I'll probably get lynched for saying this, but for my ears I've never found a DSP system that is as good as a pure analog system... Move over, Tom, we're in the same boat! VE7XF Getting crowded, hope it´s a big boat, I´m in there too. Jim SM2EKM __ 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] Regarding the K3 and high QRN levels
Me too! I'm not a K3 owner but I've had one here in the shack the past few weeks. Judicious use of the AGC settings has made it noticeably quieter and sweeter sounding than it was originally but as with all DSP radios I've heard it still 'sounds' harsh/rough. The primary box here is an Orion 565 and my baseline was coming from a TS940, maybe not the last word in ultimate receive performance but still a good radio, that together with a Collins S line have a quality of audio reproduction that I could listen too for hours on end. All rigs are still on line for comparison so not much guess work. By contrast I find the DSP radios a little tiring to say the least, maybe it's the audio circuitry itself, the O565 uses a TDA1013B, what does the K3 use? I find that reducing the filter taps from the default 199 makes the audio smoother, though that brings other issues, can the filter taps be changed with the K3? Cheers Martin, HS0ZED -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jan Erik Holm Sent: 09 July 2010 13:38 To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Regarding the K3 and high QRN levels On 2010-07-09 00:02, ve7xf wrote: I'll probably get lynched for saying this, but for my ears I've never found a DSP system that is as good as a pure analog system... Move over, Tom, we're in the same boat! VE7XF Getting crowded, hope it´s a big boat, I´m in there too. Jim SM2EKM __ 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] Regarding the K3 and high QRN levels
Dear OMs and YLs Sometime this forum produces some fine insights and guidance. This and the recent answers to the use of selectivity and noise controls have been helpful. Perhaps once the K3 design stabilizes, the manual can be upgraded to include more assistance but then I hope the K3 continues to progress and maybe half of us never carefully read the manual. It would also seem that we all have our own approaches but this forum allows us to learn from each other and perhaps prompts Elecraft to make adjustments - God bless them. TenTec has similar problems with newbie users learning to operate the radio and I believe the updated Omni was a partial answer for these users. A friend was even recommended the use of the Pro 3 over the Orion II as some thought it too difficult to operate. The K3 is a rig you grow into and grow up with. It can be used as an appliance at first and then one starts learning. A process which does not stop as the radio continues to be improved. Thanks to all of you for these questions, answers, insights and observations in this web based classroom. 73 Doug EI2CN __ 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] K2 receiver problem and signal tracing question
Robert - I built the noise generator on the Elecraft site and used it, I don't know what it's output is as I don't have an oscilloscope. Sorry to hear that you have trouble after installing the SSB. John NQ3RP -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-receiver-problem-and-signal-tracing-question-tp5272963p5273857.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] Elecraft Digital modes...
As I was trying to point out before, the availability of a variety of modes on rigs like the K3 encourages a variety of operating styles. My observation, like that of the two appended remarks, is that modes such as RTTY, PSK, Olivia and others seem to encourage a bit more rag-chewing than does, say, high-speed CW. I use these modes on my K3/100 and on my K2/100 before it, and both boxes perform wonderfully. It is a pity that a weak-signal mode like Olivia 500/16 is not more used on 6 meters. Even on 2 meters,such modes are probably worth trying even though multi-pathing becomes a relevant problem. My favorite mode has become PSK31 -- it is wonderfully conservative of band-width, and is reasonably useful even when conditions are not perfect. Olivia 500/16 is less often encountered, but it is quite astonishing to find text rising like Lazarus from the noise... The point of all this palaver would seem to be use the capabilities of the new-age transceiver to their fullest. This is a plug for the K3, which does it all in fine form, but also a resounding hurrah! for software oriented hams producing outstanding software like fldigi. Not all the newest transceivers on the market have these capabilities. Between the K2 and the K3 I owned a Flex 3000, which (once set up) worked the digital modes quite well with fldigi. However, it was almost unusable on CW. Its greatest attraction seemed to be with operators who wanted high-quality AM(!), a retrograde tendency if ever there was one. John Ragle -- W1ZI = On 7/9/2010 12:21 AM, Joe Planisky wrote: (JLR edited) I've had good luck finding rag chews using the Olivia mode(its) slowness seems to make it unpopular with the RST-QTH-Name-73 crowd...the slow speed also seems to encourage rag chewing. On Jul 8, 2010, at 7:04 PM, Don Cunningham wrote: (JLR edited) ...I spend DAYS looking for a good, RTTY ragchew, unless one of my old friends shows up on frequency. ... I thought maybe it was a change in technology, so geared up for PSK, but got the very same... __ 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] Regarding the K3 and high QRN levels
The K3 noise blanker can be either IF (analog) based or DSP based (or both). A Noise Blanker does exactly as the term says, it creates a hole in the signal path for the time of the noise - if the holes are too big, distortion of the received signal will take place - how aggressive those 'holes' are depends on the settings used, and those settings are under control of the operator. I understand NB 'width' and 'depth' controls (for lack of better terms) on other radios, so I know what's happening as I adjust them. I am, however, confounded by the K3 settings - which one is 'wider'?, which one is 'deeper'? Increased or decreased effect with advancing numbers? Am I overooking something in the manual? An explanation would relieve some of my frustration with the K3. Then we can work on the keyed PTT and the reverse CW. VE7XF __ 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] Short QSO's (was Re: 6M CW)
The Johnson T-R switch came in two iterations, as I recall. The first one suffered from suck-out, as did the second, but less so. Signal suckout occurs because the tank circuit in the transmitter presents a low impedance when the tube end of the tank is misterminated during key-up (resting or receiving) periods. Remember a tank circuit is also an artificial or lumped transmission line that often looks like it is 100-140 degrees long electrically, so the impedance at the end going to the 50 ohm cables can be very low when the tube is not conducting..shorting the transmission line for received signals. If you would have added around 40-80 degrees of extra coax between the rig and the T/R switch tap point it would have cured the signal suck-out. For a very short time I ran my B+ through the second unused blade of my knife switch so I could use one 300 volt supply for my receiver and transmitter. Good training in eye-hand coordination. __ 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] Short QSO's (was Re: 6M CW)
Thanks Bill, Joe and Alan for your observations. I didn't mean to continue a thread into oblivion so that's the reason I changed the title, hi. Now it has changed into T/R switching. Oh well, that's the nature of the reflector and a reason it is SO hard to search the archives. Joe, I'll try Olivia and see what I find. I just miss the old commradery (sp?) of the former, talkative RTTY bunch. It has nothing to do with being old, as I was younger and most of them had full time jobs and were busy building besides. It was just a gone and forgotten time, I guess. 73 all and enjoy your K3. There, some Elecraft content, hi. 73, Don, WB5HAK __ 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] K2 receiver problem and signal tracing question
Robert, Yes, the recommended signal level is quite high, and purposely so - it is high enough to read the levels on an RF Probe. If you are using an oxcilloscope (with a 10X probe please), you can use a lower level, just be certain the level is sufficient to be seen above the noise the probe picks up - if the level does not decrease when you turn the generator off, your 'scope is only seeing noise. There is not a lot that the installation of the KSB2 option can do to kill receive, especially if you restored the jumpers, so the signal tracing is the way to go, you may find the problem anywhere in the receive path. Do check the BFO and VFO injection levels first. I would suspect the BFO as the first 'culprit' - the level at U11 pin 6 must be greater than 200 mV peak to peak. 73, Don W3FPR Robert Greenwalt wrote: Hi My K2 used to receive nicely. Good strong signals on various bands, I was able to use a noise generator and spectrograph program to tune the filters, etc. Then I added the ssb kit and receiving seemed to fall way off. I removed the kit, re-soldered the jumpers and resistor and still receiving is bad. I can hear occasional signals, but nothing makes the S meter move. I can hear a slight difference between the noise generator being on and off, but not enough to get a hump on the spectrograph. A sad state. So I'm going to embark on a signal tracing adventure, but I have a question: The instructions say the signal generator should be outputting .14 Vrms according to the RF probe - is that reasonably accurate? If I use an oscilloscope instead should I be getting .14Vrms (.2Vp or .4Vpp)? That seems high when the s9 reading corresponds to 50 uV.. I just want to make sure I'm not going to fry something pumping in 20 uV. Thanks Robert K6RJG __ 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] VHF Diversity
I've been making a few recordings of signals on 6m during recent Es events, using polarisation diversity and the K3 subrx. The results are quite amusing - see www.g3tct.co.uk/diversity.html BTW the K3 has been great - 13 new dxcc on 6m and 3 new ones on 4m in May and June. 73 Graham K5RC said Thanks to G0AFH for reminding me of how we did diversity on VHF years ago. I have three six meter yagis on different towers, separated by as much as 150' horizontal and 40' vertical distances. I am going to put a switch in at the AUX input to allow one of the yagis to be dedicated to the diversity antenna. Stay tuned! __ 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] K3-EME
Hello all, I have been thinking of buying another K3 for My 2 meter EME station . Would like to knew if there is anyone doing this and what kind of power amp they are using. I know that the 2M output would drive my TE-System Power amp to about 350 watts. However later I am planning on a power amp with more output. Thanks 73 Ken K5DNL __ 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] Regarding the K3 and high QRN levels
Have you looked at page 25 of the latest manual? http://www.elecraft.com/manual/K3_Owner%27s_Manual_Rev_D7sm.pdf NB and NR settings are explained there. Also, regarding NR settings, this was posted a while back by Lyle: http://www.mail-archive.com/elecraft@mailman.qth.net/msg81591.html in a discussion of changes to NR being made at that time (affecting settings F1-1 through F4-4, the fewer taps, the more aggressive). However there has been further change since then (e.g. the mixed settings described in the manual were restored later) so that explanation may or may not be current anymore. The manual plays it safe, only saying In general, the higher the number, the more aggressive the noise reduction. without being specific about the meaning of the 2 digits in the setting. Bob NW8L On Fri, Jul 9, 2010 at 5:23 AM, ve7xf ve...@dccnet.com wrote: I understand NB 'width' and 'depth' controls (for lack of better terms) on other radios, so I know what's happening as I adjust them. I am, however, confounded by the K3 settings - which one is 'wider'?, which one is 'deeper'? Increased or decreased effect with advancing numbers? Am I overooking something in the manual? An explanation would relieve some of my frustration with the K3. Then we can work on the keyed PTT and the reverse CW. VE7XF __ 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] VHF Diversity
K3 Fellows take a listen to these! Very neat setup and great recordings. Graham, Thanks for the link. VERY interesting recordings and system. You have much to be studied on your website. The recordings are very well done and it sounds like you have a wonderfully quiet 6m location. TNX and 73 Bill K0AWU EN37ed __ 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] Regarding the K3 and high QRN levels
I've found that if you do the daughter card audio mod (3.5Khz audio roll off) on the K3's DSP board that you will find listening to the audio for hours upon hours MUCH easier on the ears. I was able to tell the difference as soon as I turned the rig back on. It's not one of those kinds of things that you say wow, that sounds so much better! it's more like you say to yourself, wow, I'm not getting tired out listening to all this noise. It's more of a feeling than a sound. So when people ask me, does it sound better, my answer is no, but it sure does feel a lot more comfortable. This could be the fatigue you're speaking about Martin. From: hs0...@csloxinfo.com To: elecraft@mailman.qth.net Date: Fri, 9 Jul 2010 14:12:26 +0700 Subject: Re: [Elecraft] Regarding the K3 and high QRN levels Me too! I'm not a K3 owner but I've had one here in the shack the past few weeks. Judicious use of the AGC settings has made it noticeably quieter and sweeter sounding than it was originally but as with all DSP radios I've heard it still 'sounds' harsh/rough. The primary box here is an Orion 565 and my baseline was coming from a TS940, maybe not the last word in ultimate receive performance but still a good radio, that together with a Collins S line have a quality of audio reproduction that I could listen too for hours on end. All rigs are still on line for comparison so not much guess work. By contrast I find the DSP radios a little tiring to say the least, maybe it's the audio circuitry itself, the O565 uses a TDA1013B, what does the K3 use? I find that reducing the filter taps from the default 199 makes the audio smoother, though that brings other issues, can the filter taps be changed with the K3? Cheers Martin, HS0ZED -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jan Erik Holm Sent: 09 July 2010 13:38 To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Regarding the K3 and high QRN levels On 2010-07-09 00:02, ve7xf wrote: I'll probably get lynched for saying this, but for my ears I've never found a DSP system that is as good as a pure analog system... Move over, Tom, we're in the same boat! VE7XF Getting crowded, hope it´s a big boat, I´m in there too. Jim SM2EKM __ 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 _ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_2 __ 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] Regarding the K3 and high QRN levels
Other than not reducing bandwidth appropriately, or not knowing there is more than one NR setting, the greatest bar to satisfactory noise reduction in the K3 is running RF gain and preamp/att settings too loud. Band noise needs to be reduced to only moderately loud, or less, first by reducing PRE/ATT settings and then reducing RF gain. I have begun to wonder about adding a slow responding auto PRE/ATT/RF mode which sensed the levels of noise and auto set the PRE/ATT and several step reductions of RF gain until band noise was properly ranged for processing. At least then one could say to TRY the AUTO PRE/RF option without having to explain the mechanics of doing it manually. Or, perhaps, sinisterly, simply make this happen in the firmware without telling anyone. 73, Guy. __ 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] Regarding the K3 and high QRN levels
That sounds amazingly like automatic gain control, something I thought you ride the r-f gain control types studiously avoided. --- On Fri, 7/9/10, Guy Olinger K2AV olin...@bellsouth.net wrote: Or, perhaps, sinisterly, simply make this happen in the firmware without telling anyone. __ 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-EME
Hi Ken, Gene, KB7Q, has been using his K3 for 6M EME. Not sure if he has the 2M module yet. He modified and old Dentron amp (the MLA as I recall). Been pondering adding the 2M module to one of my K3s... 73, Julius - Julius Fazekas N2WN Tennessee Contest Group http://www.k4ro.net/tcg/index.html Tennessee QSO Party http://www.tnqp.org/ Elecraft K2/100 #4455 Elecraft K3/100 #366 Elecraft K3#1875 -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-EME-tp5274516p5275256.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] K3: Noise reduction tutorial/primer available?
Excellent thread, several fine responses. This is one for Wayne and/or Eric to weigh in upon with Elecraft concise, straight talk this is how to use the NB and NR. Over to you guys! __ 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-EME
8877 --- On Fri, 7/9/10, Ken Roberson kwrober...@yahoo.com wrote: Hello all, I have been thinking of buying another K3 for My 2 meter EME station . Would like to knew if there is anyone doing this and what kind of power amp they are using. I know that the 2M output would drive my TE-System Power amp to about 350 watts. However later I am planning on a power amp with more output. Thanks 73 Ken K5DNL __ 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] Regarding the K3 and high QRN levels
It's more of a feeling than a sound - I have heard that if you use Boston speakers you'll get More than a Feeling'. Steve N4LQ - Original Message - From: The Smiths notforc...@hotmail.com To: hs0...@csloxinfo.com; Elecraft Reflector elecraft@mailman.qth.net Sent: Friday, July 09, 2010 12:20 PM Subject: Re: [Elecraft] Regarding the K3 and high QRN levels I've found that if you do the daughter card audio mod (3.5Khz audio roll off) on the K3's DSP board that you will find listening to the audio for hours upon hours MUCH easier on the ears. I was able to tell the difference as soon as I turned the rig back on. It's not one of those kinds of things that you say wow, that sounds so much better! it's more like you say to yourself, wow, I'm not getting tired out listening to all this noise. It's more of a feeling than a sound. So when people ask me, does it sound better, my answer is no, but it sure does feel a lot more comfortable. This could be the fatigue you're speaking about Martin. __ 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: Noise reduction tutorial/primer available?
There was straight talk about NR from Lyle Johnson (who designed and implemented the algorithms) in his reflector posts of 8/25/09 and 8/27/09 as well as the information in the Firmware Release Notes for version 3.30 (avaliable using the K3 Utility Help pulldown). Page 25 of the K3 manual has a comprehensive description of the tools available - Reducing Interference and Noise section. The manual content is Wayne's work, so those who know most about those implementations have already spoken. I am not certain how much more authoritative information you are seeking. As far as explicit Here is how you use it - each individual case or instance of noise is different and will require different treatment. Each user will have to cycle through the settings available to see which works best - the result is a compromise, there is little that can move a signal out of the noise and provide a completely distortion-free and clear copy signal - copy will be improved, but just how much is improved and how much distortion is tolerable is a question each operator must answer. 73, Don W3FPR w0...@aol.com wrote: Excellent thread, several fine responses. This is one for Wayne and/or Eric to weigh in upon with Elecraft concise, straight talk this is how to use the NB and NR. Over to you guys! __ 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: Noise reduction tutorial/primer available?
On Jul 9, 2010, at 3:00 PM, Don Wilhelm wrote: I am not certain how much more authoritative information you are seeking. As far as explicit Here is how you use it - each individual case or instance of noise is different and will require different treatment. At least for myself, it would be useful to have a paragraph or two that could be titled K3 NB and NR for Dummies and might look something like this: Each operator and location will experience unique noise sources and conditions. In order to best use the NB and NR tools, a certain amount of experimenting is required. That being said, here are some general guidelines for using NB and NR tools under very generic situations. Each operator will have to play around with these settings for their own situation! NB: Lightning noise: (?) Power line noise: XYL is vacuuming the house: ? Plasma TV noise: NR: Unlike the NB system, the NR tools are for combating random noise of an unknown (or random) source. In this case, a starting place for using the tool might be easier based on mode rather than source: SSB: (my favorite is 5-1) CW: ??? DATA: OFF then again, this would be better in a WIKI than the official documentation... Take care Gary / k3wow __ 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] Regarding the K3 and high QRN levels
I should also like to point out that in a thread over a year ago, I mentioned that I thought the radio should be smart enough to know to do this. http://elecraft.365791.n2.nabble.com/K3-on-channel-strong-signal-overload-td2785612i20.html#a2801033 --- On Fri, 7/9/10, Guy Olinger K2AV olin...@bellsouth.net wrote: Or, perhaps, sinisterly, simply make this happen in the firmware without telling anyone. __ 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] Regarding the K3 and high QRN levels
Hmmm...that must be AGC, AFAIK my K3 does have AGC and it works! Riding the RF was done back in the 50´ties. Ahm, you don´t mean to tell me that riding the RF is needed on a super duper 2000 century CPU DSP whiz bang design? If so we aren´t doing any progress here, by golly we are walking backwards Jim SM2EKM - On 2010-07-09 18:37, Wes Stewart wrote: That sounds amazingly like automatic gain control, something I thought you ride the r-f gain control types studiously avoided. --- On Fri, 7/9/10, Guy Olinger K2AVolin...@bellsouth.net wrote: Or, perhaps, sinisterly, simply make this happen in the firmware without telling anyone. __ 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: Noise reduction tutorial/primer available?
Gary, Have you read column 2 of page 25 in the manual? What it says is very close to what you have requested - except for explicitly stating that 'some experimentation is required'. It does say which noise sources the IF Noise Blanker is better suited for, and which the DSP Noise Blanker attacks more readily. Further down, it states that the more aggressive NR settings will make the signal sound hollow. I don't know just how much more information would be meaningful. There is no one setting that works best for any one type of noise all the time - how far the noise source is from your antenna and how it propagates are additional variables. A recipe for any particular situation could become quite complex. To be a valid chart the noise characteristics would have to be expressed in terms of the rise time, duration, and fall times of the noise present *at* the K3 input (not at the source of noise). It makes no sense to me to attach the antenna feedline to a spectrum analyzer to determine the characteristics of the noise before selecting which one to use on the K3. I think it much easier just to try the various settings (given the guidelines already in the manual) and find which one sounds best to your ears at that particular time - most likely the best will be different tomorrow because the signal affects the best choice as well as the noise type, and the signal will change with propagation changes too. 73, Don W3FPR Gary Dezern wrote: At least for myself, it would be useful to have a paragraph or two that could be titled K3 NB and NR for Dummies and might look something like this: Each operator and location will experience unique noise sources and conditions. In order to best use the NB and NR tools, a certain amount of experimenting is required. That being said, here are some general guidelines for using NB and NR tools under very generic situations. Each operator will have to play around with these settings for their own situation! NB: Lightning noise: (?) Power line noise: XYL is vacuuming the house: ? Plasma TV noise: NR: Unlike the NB system, the NR tools are for combating random noise of an unknown (or random) source. In this case, a starting place for using the tool might be easier based on mode rather than source: SSB: (my favorite is 5-1) CW: ??? DATA: OFF __ 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] Regarding the K3 and high QRN levels
Jim, Riding the RF Gain is not necessary in the K3 nor any other modern receiver. However, reducing the RF Gain to the point where the noise level on the band is reduced to a tolerable level helps a lot with operator comfort while tuning. Yes, switch to another band or another antenna and that optimum setting will be different. AGC does not discriminate between a bunch of signals on a band and the atmospheric noise that is coming in from the antenna. 73, Don W3FPR Jan Erik Holm wrote: Hmmm...that must be AGC, AFAIK my K3 does have AGC and it works! Riding the RF was done back in the 50´ties. Ahm, you don´t mean to tell me that riding the RF is needed on a super duper 2000 century CPU DSP whiz bang design? If so we aren´t doing any progress here, by golly we are walking backwards Jim SM2EKM __ 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] Regarding the K3 and high QRN levels
Thanks to all who have replied. You have helped me learn more about the K3 and it's capabilities. 73, de Nate -- The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true. Ham radio, Linux, bikes, and more: http://n0nb.us/index.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] Regarding the K3 and high QRN levels
Nate, Whilst the K3 may not be the 'Holy Grail', I have owned enough different HF transceivers to know it is the closest yet to achieving that goal. It does take time to learn the capabilities of any excellent quality transceiver and the K3 is no exception, but over time you do learn how to use the many tools Elecraft have placed in the K3 and it has been a learning curve for me and when I now operate 'other' manufacturers equipment I am unable to find any of them capable of producing the quality of signals that I have become accustomed too. Add to the above my hearing issues, (Tinnitus) and the difference is truly remarkable in my case. The assistance provided by posters on the reflector is an added bonus. 73's Gary On Sat, Jul 10, 2010 at 8:12 AM, Nate Bargmann n...@n0nb.us wrote: Thanks to all who have replied. You have helped me learn more about the K3 and it's capabilities. 73, de Nate -- The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true. Ham radio, Linux, bikes, and more: http://n0nb.us/index.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 -- Gary VK4FD - Motorhome Mobile http://www.qsl.net/vk4fd/ K3 #679 For everything else there's Mastercard!!! __ 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] D104 mic
Anyone ever use a D-104 (non amp) on a K3. How does it sound? Chris W7CTH __ 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] K3 cross-band split
Trying to get set up for the IARU with my new subRX, and want to use SO2V mode with N1MM logger. It works fine when both VFOs are on the same band. But when the logger tries to put K3 into split mode in a cross-band situation, K3 says SPL N/A . There is a note in the manual saying that this could be due to incompatible modes on the VFOs, but both are on CW. No doubt I'm missing something pretty simple. Any ideas what? Thanks and 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] D104 mic
Chris, Unmodified, it will probably sound terrible (very 'bright with lots of highs, weak lows), but with a bit of work, it will sound great - just like Astatic intended. The D-104 element is either crystal or ceramic, and wants to work into a high impedance (like the grid of a vacuum tube with a 1 megohm 'grid leak' resistor) load. Modern transceivers present a much lower impedance load (nominally 600 ohms). I have seen some comments that the simple insertion of a 1 megohm resistor in series with the AF line is all that is needed. That may be the first thing to try. I strongly suggest you use the K3 monitor function with the K3 in TEST mode and record your audio on the computer - listen to the recording to see what it sounds like (that is almost impossible to judge while listening With a single FET buffer or an op amp between the D-104 and the K3 (or any other transceiver), the D-104 will come to life just as it did with the old vacuum tube rigs. An op amp solution is a natural because the characteristic of an op amp is very high input impedance and low output impedance - perfect for the D-104. An LM358 wired as a unity gain buffer should do the job nicely, and for the voltage swings involved (small) the LM358 can be powered from the +8 volts available at the front microphone jack pin 6. If you would want to use the rear microphone jack, the FET solution would be better because the voltage to drive the FET can be supplied by turning bias on. I am not going to give you a circuit diagram because I have not developed and tried it out. There is another solution - that is to replace the original element with an electret element, or with a Heil HC-4 or HC-5 element (Heil offers a kit for that). 73, Don W3FPR Chris Hembree wrote: Anyone ever use a D-104 (non amp) on a K3. How does it sound? Chris W7CTH __ 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 cross-band split
Craig, Do you have the menu set to VFO IND? If not, you cannot operate the K3 cross-band split. Do note the caution documented in the manual at the end of page 37. 73, Don W3FPR Craig D. Smith wrote: Trying to get set up for the IARU with my new subRX, and want to use SO2V mode with N1MM logger. It works fine when both VFOs are on the same band. But when the logger tries to put K3 into split mode in a cross-band situation, K3 says SPL N/A . There is a note in the manual saying that this could be due to incompatible modes on the VFOs, but both are on CW. No doubt I'm missing something pretty simple. Any ideas what? Thanks and 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 cross-band split
Thanks, Don, for the suggestions. I did have VFO IND set to Yes. I'm also using a dedicated RX antenna on the AUX input of the subRX. So both of those seem to be set up OK. 73 Craig AC0DS Do you have the menu set to VFO IND? If not, you cannot operate the K3 cross-band split. Do note the caution documented in the manual at the end of page 37. __ 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] D104 mic
Hi, Chris, Heil makes a conversion kit for the D-104. I am using it and have had great results. If you would like more information, please see my eHam review at http://www.eham.net/reviews/review/65769 73, John, WA6L -- View this message in context: http://elecraft.365791.n2.nabble.com/D104-mic-tp5276371p5276520.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] [K3] FS: KFL3A-500
I changed around a couple of filters on my K3 and ended up with an extra 500Hz filter. If anyone needs it, I will ship it postpaid to any USA address for $65. Thanks and 73, John, WA6L -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FS-KFL3A-500-tp5276525p5276525.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 cross-band split
Craig, In that case, I would investigate what commands N1MM is sending to the K3. 73, Don W3FPR Craig D. Smith wrote: Thanks, Don, for the suggestions. I did have VFO IND set to Yes. I'm also using a dedicated RX antenna on the AUX input of the subRX. So both of those seem to be set up OK. 73 Craig AC0DS Do you have the menu set to VFO IND? If not, you cannot operate the K3 cross-band split. Do note the caution documented in the manual at the end of page 37. __ 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] D104 mic
It will sound great if you add a J310 or similar JFET source follower. Very flat clean response. A source follower is very simple. Use a low voltage .01 uF or .05 uF disc cap to the gate. Use a 100k to 1 meg ohm resistor from gate to ground. Put a 560 ohm source resistor to ground, and couple the source to the K3 through a .47 uF cap. The drain is bypassed and decoupled to a 9 volt battery or clean 12 volt supply. If you have a lot of RF you might need to decouple the audio output line. The size of the gate resistor will control loading on the D104 and the frequency response. The higher the resistance the more the low frequency response. Until I started using a Sennheiser computer headset I used a D104 head on all my rigs. 73 Tom - Original Message - From: Chris Hembree w7...@yahoo.com To: elecraft@mailman.qth.net Sent: Friday, July 09, 2010 7:11 PM Subject: [Elecraft] D104 mic Anyone ever use a D-104 (non amp) on a K3. How does it sound? Chris W7CTH __ 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] D104 mic
On Fri, Jul 9, 2010 at 5:00 PM, Don Wilhelm w3...@embarqmail.com wrote: Unmodified, it will probably sound terrible (very 'bright with lots of highs, weak lows), but with a bit of work, it will sound great - just like Astatic intended. My experience is different. When I first got my K3, I used an unmodified crystal-element D-104 I've had since 1956. No amps, no anything. I didn't do anything special with the K3 except adjust gain and ALC controls per the K3 manual. On the air checks with guru K9YC and on the 3830 net after an NCCC Sprint resulted in superb voice-quality reports. So, plug it in and give it a try (with on-the-air checks from people you trust). 73, Hank, W6SX Mammoth Lakes, California Elevation 8083 feet in John Muir's Range of Light __ 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] FS: KFL3A-500
Already sold. Thanks! John, WA6L -- View this message in context: http://elecraft.365791.n2.nabble.com/K3-FS-KFL3A-500-tp5276525p5276608.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] Regarding the K3 and high QRN levels
AGC is instant and dynamic, and does not vary RF gain, PRE/ATT settings which are static unless the user changes them. RF gain, PRE, and ATT result in numeric advice to the CPU, rather than being in direct control of a circuit or device as in an analog receiver. The CPU in turn drives the actual circuit devices from it's many outputs. There are many uses for this indirect linking. At issue is that the main smart AGC is digital signal processing, and is *AFTER* the analog to digital conversion (ADC). The RF gain (which is really IF gain), PRE and ATT are before the ADC, and improperly setting those can squeeze the noise into the high numerical range in the conversion or even engage the defensive hardware AGC which is better off not being engaged. The defensive AGC is analog, has no smarts, and unfortunately must reduce signal-to-noise in doing its job of preventing ADC input overload. Those who understand how the rig works will throttle back the pre-digital controls to where noise is at most moderately loud to obtain best operation of digital features. What I am suggesting is that in an AUTO novice mode a slow (rate of human turning the RF gain) throttling back can be set (and then left alone) by the radio for those who are not into the theory and do not recognize the source of their complaints as being caused/worsened by their misadjustment of RF gain, PRE and ATT. Leaving PRE on and RF gain at max on all bands regardless causes the digital AGC to increase or reduce the noise to the same level as the wanted signal in pauses. This reduces the effectiveness of the NR algorithms. Those who ride their own RF gains would not be using this. 73, Guy. On Fri, Jul 9, 2010 at 12:37 PM, Wes Stewart n...@yahoo.com wrote: That sounds amazingly like automatic gain control, something I thought you ride the r-f gain control types studiously avoided. --- On *Fri, 7/9/10, Guy Olinger K2AV olin...@bellsouth.net* wrote: Or, perhaps, sinisterly, simply make this happen in the firmware without telling anyone. __ 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-EME
I have used the k3 on 144 EME with a 400w am6154 amp and no preamp, see http://g4fre.com/144eme.htm I have now upgraded to an i0jxx 500w solid state amp see http://g4fre.com/500w144pa.htm It only needs 3w of drive from the K3 for full output The K3 mainly gets used as an I.F. on 1296 thro 5760MHz; my main interest. The SDRIQ used as a panadaptor sure helps track down the activity Dave WW2R Message: 41 Date: Fri, 9 Jul 2010 07:27:13 -0700 (PDT) From: Ken Roberson kwrober...@yahoo.com Subject: [Elecraft] K3-EME To: Elecraft Elecraft elecraft@mailman.qth.net Message-ID: 670722.3241...@web32107.mail.mud.yahoo.com Content-Type: text/plain; charset=us-ascii Hello all, I have been thinking of buying another K3 for My 2 meter EME station . Would like to knew if there is anyone doing this and what kind of power amp they are using. I know that the 2M output would drive my TE-System Power amp to about 350 watts. However later I am planning on a power amp with more output. Thanks 73 Ken K5DNL __ 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] D104 mic
Use a 100k to 1 meg ohm resistor from gate to ground. Put a 560 ohm source resistor to ground, and couple the source to the K3 through a .47 uF cap. I agree with comments from Tom and Don. However, the leak resistor from the FET's gate to ground usually isn't necessary as the crystal cartridge itself often provides ample leak to bias the FET. The source resistor can be calculated to set mid-point bias a bit more precisely by taking the reciprocal of the FET's transconductance (gm or gfs) value. For example, the Fairchild MPF-102 is specified with a gm value between 2000 uS and 5000 uS. The geometric mean of those values is about 3,000 uS. The reciprocal value is 333. So, a 330-ohm source resistor to ground is a good choice when the actual gm value is unknown. I would stay away from op-amp solutions for a number of reasons: First, unless a bi-polar supply is used, a voltage divider must normally be set up to bias the op-amp's non-inverting input, and consequently, the op-amp output to half the supply voltage. However, some op-amps are designed to operate from single supplies, contain internal dividers, and require no external divider components. Second, the parts count can get to be quite a bit more than a single FET. Finally, unless a JFET-input op-amp or biFET op-amp is used (e.g., Texas Instruments TL071), obtaining stable operation and achieving a high input Z into the megohm range is pretty difficult. The biFET designs can more easily achieve this. As Don pointed out, some folks use a 1 to 5 meg resistor between the D-104 cartridge and the low-Z input of a transceiver. That re-establishes balance in frequency response from the cartridge but it also sets up a very asymmetric voltage divider, the equivalent of which is a pot with its wiper arm nearly at ground potential. Often, the result is low level and poor audio SNR. All things considered (RF immunity, single supply, low parts count, low current, super high input Z, and very low output Z), it's pretty hard to beat a single FET when used as a source follower with crystal mics. Although I do own a condenser mic, my primary mic is ca. 1935 Shure 70H crystal type with a JFET interface. With that combination, response is reasonably flat to about 80 Hz. Paul, W9AC __ 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] Regarding the K3 and high QRN levels
I'm sorry, but you can't have it both ways. RF (i-f) gain as implemented in the K3 operates on the post-filter (8 MHz) i-f amplifier. The control voltage is derived at least two (perhaps three) ways. The post 2nd mixer i-f amplifier (15 KHz) output is detected and if a threshold is reached, so-called hardware AGC is applied to the post-filter amplifier. The manual i-f gain control is derived from an encoder, processed by the DSP and summed to the same post-filter amplifier. If I remember what Lyle told me the last time I saw him, there is also a contribution to this control voltage from the signal processing DSP. I could be mistaken on this last point, but no matter, for the sake of this discussion it's immaterial. So as far as the 8 MHz if amplifier is concerned, it can't tell manual r-f gain from hardware AGC. So when you worry about AGC degrading SNR (it does) a reduction in i-f gain does exactly the same thing! In fact, as I demonstrated to Lyle over a year ago, before the R-F gain calibration routine, my K3 suffered noticeable SNR degradation even on S9+50 dB signals, with the slightest engagement of the r-f gain control. This is because of the wacky gain control characteristics of the FET(s), which can have Gm variations of 2:1, device-to-device. I submit that a modern DSP radio with all of the smarts this suggests, should not even need an r-f (or i-f) gain control. I've used spectrum analyzers for over 30 years (even before computer control) that slaved the input attenuator and the i-f gain control to maximize dynamic range without overloading the front-end mixer. If you uncoupled the controls, the test for overload was to change the input attenuator 10 dB and see if the display changed 10 dB. If it was less than 10 dB then the mixer was in compression. If this trivial calculation can't be made in a DSP radio, then I want an analog receiver back. To be sure, AGC development isn't trivial, particularly with the latency that seems to be associated with DSP. (I'm not a digital guy, so I'm guessing here) But even in analog receivers, group delay is an issue with control loop stability. In a homebrew received I did in the 70's I had to pick off i-f for AGC detection before the tail-end-of-the-if-crystal filter to stabilize the loop. But with attack time set by i-f and decay time set by audio, it worked flawlessly. I know it can be done digitally, if my TS-870 is any measure. I never touch the manual gain control on that radio (or my K3 for that matter.) If a human has to intervene, there is something wrong with the ACG design. Wes --- On Fri, 7/9/10, Guy Olinger K2AV olin...@bellsouth.net wrote: AGC is instant and dynamic, and does not vary RF gain, PRE/ATT settings which are static unless the user changes them. RF gain, PRE, and ATT result in numeric advice to the CPU, rather than being in direct control of a circuit or device as in an analog receiver. The CPU in turn drives the actual circuit devices from it's many outputs. There are many uses for this indirect linking. At issue is that the main smart AGC is digital signal processing, and is *AFTER* the analog to digital conversion (ADC). The RF gain (which is really IF gain), PRE and ATT are before the ADC, and improperly setting those can squeeze the noise into the high numerical range in the conversion or even engage the defensive hardware AGC which is better off not being engaged. The defensive AGC is analog, has no smarts, and unfortunately must reduce signal-to-noise in doing its job of preventing ADC input overload. Those who understand how the rig works will throttle back the pre-digital controls to where noise is at most moderately loud to obtain best operation of digital features. What I am suggesting is that in an AUTO novice mode a slow (rate of human turning the RF gain) throttling back can be set (and then left alone) by the radio for those who are not into the theory and do not recognize the source of their complaints as being caused/worsened by their misadjustment of RF gain, PRE and ATT. Leaving PRE on and RF gain at max on all bands regardless causes the digital AGC to increase or reduce the noise to the same level as the wanted signal in pauses. This reduces the effectiveness of the NR algorithms. Those who ride their own RF gains would not be using this. 73, Guy. __ 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] D104 mic
On Fri, 9 Jul 2010 20:47:36 -0400, Tom W8JI wrote: It will sound great if you add a J310 or similar JFET source follower. Hams spend WAY too much time hand-wringing about impedance matching in audio circuits. Audio circuits have not been impedance matched for nearly 50 years! As long as the input Z of the preamp is not so low that it loads the mic severely, everything should be fine. The input Z of the K3 mic circuit is on the order of 10K. That's pretty high, and most mics ought to be quite happy with it. For a passive mic, the downside of excessive loading is usually some modification of the frequency response, some loss of level, but no distortion. TXEQ can easily fix any response problems, and the K3 has plenty of mic gain to make up for any loss. Tom's advice is solid if it's a VERY high Z mic, BUT it may also depend on the version of D104 that you have. I haven't played with a D104 for nearly 40 years, so don't know enough about that to have an opinion that matters. :) I would first try it straight into the K3 as Hank did, adjust levels per Elecraft intructions, then get someone with good audio ears to talk you into TXEQ settings on the air. If you can't make it sound right, then follow Tom's advice and build the follower circuit. 73, Jim K9YC __ 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
