[Elecraft] K3 BUFFER MOD?
Guys, Later today I will start building my LP-PAN kit - I was wondering if the K3 Buffer mod that is recommended will void the warranty on my radio? Is it really worth the effort? Where is best place to attain parts? I have the K3 Audio line out mod kit to do figured I should probably do it all at the same time? My S/N is 1059 Thanks and 73, Bill N4ZI __ 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 BUFFER MOD?
Bill, I am sure you will get more expert advice than I can give you on this, but so far I have not found the buffer mod necessary with my LP-PAN - right now I have only a vertical antenna and have only tried the LP-PAN out on low bands, where band noise alone is clearly visible on the display even without the mod. You may feel differently if you are using directional antennas on quiet bands, but my suggestion would be to start out without the buffer mod and see how well your LP-PAN works without it. Although I have installed the Audio line out mod myself, I think it probably won't make any difference to LP-PAN operation, since the LP-PAN does not use line out. However, I found that the mod to bypass RF chokes in the ground return lines made a big difference: (http://www.elecraft.com/K3/mods/ELECRAFT_Application_Note_Improving_the_Im munity_of_the_Rear-Panel_KIO3_RS232_and_Audio_Connectors_to_RF.pdf, or go to http://www.elecraft.com/K3/k3_app_notes.htm and scroll down to the link Improving the Immunity of the Rear-Panel RS232 and Audio Connectors to RF). Before making this change, I was seeing a lot of polling noise from the radio control serial port on the PowerSDR display. Bypassing the choke in the RS232 ground return seems to have helped a lot in my case - YMMV, of course. 73, Rich VE3KI K3 #1595 N4ZI wrote: Guys, Later today I will start building my LP-PAN kit - I was wondering if the K3 Buffer mod that is recommended will void the warranty on my radio? Is it really worth the effort? Where is best place to attain parts? I have the K3 Audio line out mod kit to do figured I should probably do it all at the same time? My S/N is 1059 Thanks and 73, Bill N4ZI __ 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 BUFFER MOD?
Bill Maddock-2 wrote: Later today I will start building my LP-PAN kit - I was wondering if the K3 Buffer mod that is recommended will void the warranty on my radio? Probably not. Wayne is well aware of it and has never said the warranty would be voided. Bill Maddock-2 wrote: Is it really worth the effort? Where is best place to attain parts? Unless you want to identify extremely weak signals, perhaps not. On 160m nearly all DX signals are weak and many were not detectable without the mod. I robbed junk SMD boards for the two resistors (R8/R9) but most major suppliers carry SMD parts (e.g. Mouser, Newark, etc.) Bill Maddock-2 wrote: I have the K3 Audio line out mod kit to do figured I should probably do it all at the same time? It really doesn't matter. The mod can be done by removing only the front bottom cover, which is extremely easy to access anytime. 73, Bill -- View this message in context: http://n2.nabble.com/K3-BUFFER-MOD--tp2250715p2251203.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 Buffer Mod
Jim, The reason I ask about using regular resistors instead of SM resistors is that I don't have the correct value SM resistors. If there is a degradation in performance with film axial lead resistors I will get the SM resistors. It is not a question of qualification of mounting SM components. 73, N2TK, Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Cox Sent: Thursday, August 21, 2008 8:55 PM To: Don Rasmussen; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Buffer Mod It sounds like Tony should leave the K3 as is. Dont screw it up unless your qualified to make the mods. Jim K4JAF - Original Message - From: Don Rasmussen [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Thursday, August 21, 2008 7:06 PM Subject: [Elecraft] K3 Buffer Mod Tony, I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. IMO (in my opinion) you don't work with SMD on K3, they fly around like little fleas even if you use a pair of 15w irons to remove them. They are just that small. But you can get them off without any major damage, find them, and carefully replace them - *when necessary*. YMMV... de wb8yqj Previous message: [Elecraft] K3 Buffer Mod Next message: [Elecraft] K2/100 LOCKUP THOUGHTS? Should I expect any negative impacts if I used regular resistors in place of SM resistors for this mod? N2TK, Tony ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K3 Buffer Mod
Tony, Since this is not a high frequency area, there should be little performance difference (if any) between SMD parts and axial leaded parts. The more relevant consideration is physical fit. If you have 1/8 watt resistors it would be easier than 1/4 watt, but you should be able to get the 1/4 watt parts in there. 73, Don W3FPR N2TK wrote: Jim, The reason I ask about using regular resistors instead of SM resistors is that I don't have the correct value SM resistors. If there is a degradation in performance with film axial lead resistors I will get the SM resistors. It is not a question of qualification of mounting SM components. 73, N2TK, Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Cox Sent: Thursday, August 21, 2008 8:55 PM To: Don Rasmussen; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Buffer Mod It sounds like Tony should leave the K3 as is. Dont screw it up unless your qualified to make the mods. Jim K4JAF - Original Message - From: Don Rasmussen [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Thursday, August 21, 2008 7:06 PM Subject: [Elecraft] K3 Buffer Mod Tony, I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. IMO (in my opinion) you don't work with SMD on K3, they fly around like little fleas even if you use a pair of 15w irons to remove them. They are just that small. But you can get them off without any major damage, find them, and carefully replace them - *when necessary*. YMMV... de wb8yqj Previous message: [Elecraft] K3 Buffer Mod Next message: [Elecraft] K2/100 LOCKUP THOUGHTS? Should I expect any negative impacts if I used regular resistors in place of SM resistors for this mod? N2TK, Tony ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.6.6/1626 - Release Date: 8/21/2008 6:54 PM ___ 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] K3 Buffer Mod
Don Rasmussen wrote: I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. 17.7 dB transfer loss from RF IN to IF OUT is why... http://www.cliftonlaboratories.com/elecraft_k3_and_panadapters.htm#What_then_is_the_transfer_gain_of_the_K3_ -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp741709p759255.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
Tnx Don, I do have the correct values in 1/8w. I wouldn't think there would be a difference, but I like to ask first, just in case. Finally should get some time over the next week to get beyond page 25 of the assembly manual for my second K3. 73, N2TK, Tony -Original Message- From: Don Wilhelm [mailto:[EMAIL PROTECTED] Sent: Friday, August 22, 2008 8:10 AM To: N2TK Cc: 'Jim Cox'; 'Don Rasmussen'; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Buffer Mod Tony, Since this is not a high frequency area, there should be little performance difference (if any) between SMD parts and axial leaded parts. The more relevant consideration is physical fit. If you have 1/8 watt resistors it would be easier than 1/4 watt, but you should be able to get the 1/4 watt parts in there. 73, Don W3FPR N2TK wrote: Jim, The reason I ask about using regular resistors instead of SM resistors is that I don't have the correct value SM resistors. If there is a degradation in performance with film axial lead resistors I will get the SM resistors. It is not a question of qualification of mounting SM components. 73, N2TK, Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Cox Sent: Thursday, August 21, 2008 8:55 PM To: Don Rasmussen; elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Buffer Mod It sounds like Tony should leave the K3 as is. Dont screw it up unless your qualified to make the mods. Jim K4JAF - Original Message - From: Don Rasmussen [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Thursday, August 21, 2008 7:06 PM Subject: [Elecraft] K3 Buffer Mod Tony, I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. IMO (in my opinion) you don't work with SMD on K3, they fly around like little fleas even if you use a pair of 15w irons to remove them. They are just that small. But you can get them off without any major damage, find them, and carefully replace them - *when necessary*. YMMV... de wb8yqj Previous message: [Elecraft] K3 Buffer Mod Next message: [Elecraft] K2/100 LOCKUP THOUGHTS? Should I expect any negative impacts if I used regular resistors in place of SM resistors for this mod? N2TK, Tony ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.6.6/1626 - Release Date: 8/21/2008 6:54 PM ___ 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] K3 Buffer Mod
Don Rasmussen wrote: I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. At 08:16 AM 8/22/2008, Bill W4ZV wrote: 17.7 dB transfer loss from RF IN to IF OUT is why... But isn't that just an engineering design decision made by the Elecraft team? Since that decision was (hopefully) made with regard to the entire radio system, isn't that decision likely to be a good one? As one data point, my K3 is not modified, yet the IF panadaptor works extremely well, and PowerSDR gives peak heights approximating the true signal strengths seen at the input of the K3. When I feed in a 1 uV signal from my KG-2 signal generator, I see a definite distinct peak on the panadaptor, and when I feed in a 50 uV (S9) signal, I see a large S9 signal on the panadaptor. I am a loss to understand why you guys are quarreling with the Elecraft design in this instance. I am beginning to suspect that it is simply because it does not agree with the usual designs provided by some military contractors who are probably using an _arbitrary_ standard anyway. I would think twice before possibly damaging my radio or lowering its resale value with non-factory authorized modifications. YMMV. Jerry W4UK ___ 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] K3 Buffer Mod
The sensitivity may be adequate as a panadapter (but really only with the preamp on), but if you have ever tried to listen to a moderately weak signal with the audio output from PowerSDR-IF, it will be abundantly clear that more sensitivity is needed. PowerSDR has a very good synchronous AM detector, for example, so the combination offers listening opportunities the K3 does not yet have. I have also listened to DRM using the Dream decoder and finding that only the strongest of signals will decode properly. Knut - AB2TC Jerry Flanders wrote: Don Rasmussen wrote: I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. At 08:16 AM 8/22/2008, Bill W4ZV wrote: 17.7 dB transfer loss from RF IN to IF OUT is why... But isn't that just an engineering design decision made by the Elecraft team? Since that decision was (hopefully) made with regard to the entire radio system, isn't that decision likely to be a good one? As one data point, my K3 is not modified, yet the IF panadaptor works extremely well, and PowerSDR gives peak heights approximating the true signal strengths seen at the input of the K3. When I feed in a 1 uV signal from my KG-2 signal generator, I see a definite distinct peak on the panadaptor, and when I feed in a 50 uV (S9) signal, I see a large S9 signal on the panadaptor. I am a loss to understand why you guys are quarreling with the Elecraft design in this instance. I am beginning to suspect that it is simply because it does not agree with the usual designs provided by some military contractors who are probably using an _arbitrary_ standard anyway. snip - AB2TC - Knut -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp741709p759729.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] K3 Buffer Mod
Bill, just to clarify: - I assume you can handle the SMT without any trouble or worries. - I also assume that you have a good reason to want the extra 17.7db, so go mod, be happy. But for anyone else that may not be comfortable with SMT changes, I am suggesting that before they partake in that, they understand what the mod does and how it would help them in their application. My suggestion is, that for someone that's using the standard LP-PAN + Power-SDR + E-MU 0202 setup, there is no benefit to doing the mod, as the Y coordinates in PowerSDR are adjustable (as discussed on the Yahoo LP-PAN list). Works good - lasts a long time. ;-) That's my story and I'm sticking to it. Respectfully, Don -- And sorry Tony I think you were more interested in the discrete vs. SMT packages but I wanted to clarify on this point think you got your answer. !!! [Elecraft] K3 Buffer Mod Bill W4ZV btippett at alum.mit.edu Fri Aug 22 08:16:40 EDT 2008 Previous message: [Elecraft] K3 Buffer Mod Next message: [Elecraft] K3 Buffer Mod Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Don Rasmussen wrote: I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. 17.7 dB transfer loss from RF IN to IF OUT is why... http://www.cliftonlaboratories.com/elecraft_k3_and_panadapters.htm#What_then_is_the_transfer_gain_of_the_K3_ ___ 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] K3 Buffer Mod
Jerry Flanders wrote: At 08:16 AM 8/22/2008, Bill W4ZV wrote: 17.7 dB transfer loss from RF IN to IF OUT is why... But isn't that just an engineering design decision made by the Elecraft team? Since that decision was (hopefully) made with regard to the entire radio system, isn't that decision likely to be a good one? As one data point, my K3 is not modified, yet the IF panadaptor works extremely well, and PowerSDR gives peak heights approximating the true signal strengths seen at the input of the K3. When I feed in a 1 uV signal from my KG-2 signal generator, I see a definite distinct peak on the panadaptor, and when I feed in a 50 uV (S9) signal, I see a large S9 signal on the panadaptor. I am a loss to understand why you guys are quarreling with the Elecraft design in this instance. I am beginning to suspect that it is simply because it does not agree with the usual designs provided by some military contractors who are probably using an _arbitrary_ standard anyway. I would think twice before possibly damaging my radio or lowering its resale value with non-factory authorized modifications. 1uV (-107 dBm) is ~30 dB above the K3's noise floor. One of the primary reasons I wanted LP-PAN was to use either PowerSDR or CW Skimmer's waterfall to help detect very weak (i.e. noise floor) signals. Why would I want to limit myself to signals 30 dB above the noise floor? Answer: I wouldn't! Elecraft is well aware of N8LP's mod, Wayne saw no problems with it at first glance and is now considering whether to make it a production mod. Both N8LP and K8ZOA seem to feel it is not damaging the radio, etc. Begging your pardon Jerry but Elecraft does not always get everything right the first time (e.g. the HAGC mod) but fortunately they are willing to listen to data and rational arguments for potential improvements. Thankfully Elecraft is much more open-minded to improvements than most manufacturers! 73, Bill -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp741709p759820.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
Don Rasmussen wrote: Bill, just to clarify: My suggestion is, that for someone that's using the standard LP-PAN + Power-SDR + E-MU 0202 setup, there is no benefit to doing the mod, as the Y coordinates in PowerSDR are adjustable (as discussed on the Yahoo LP-PAN list). The Y coordinates of PowerSDR have nothing to do with this. Before PowerSDR ever detects a signal, there is effectively a 17.7 dB attenuator ahead of it and PowerSDR will never see any signals that are less than 17.7 dB above the noise floor. For the first week I had CW Skimmer, I thought it was terrible at decoding weak signals. Then I discovered the actual reason it wasn't had nothing to do with the Skimmer software but with the K3's transfer loss. Thinks of it this way...if you're trying to listen to an extremely weak signal, would you like a 17.7 dB attenuator between it and your ears? I don't think so. 73, Bill -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp759790p759844.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
Elecraft is well aware of N8LP's mod, Wayne saw no problems with it at first glance and is now considering whether to make it a production mod. Both N8LP and K8ZOA seem to feel it is not damaging the radio, etc. Remember to make the measurements Jack points out on his web page if you do the mod. This is to be sure the buffer transistor does not exceed its thermal ratings. 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] K3 Buffer Mod
Don Rasmussen wrote: I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. At 08:16 AM 8/22/2008, Bill W4ZV wrote: 17.7 dB transfer loss from RF IN to IF OUT is why... At 07:38 AM 8/22/2008, Jerry Flanders wrote: But isn't that just an engineering design decision made by the Elecraft team? Of course. A primary design criteria was limiting the IF output level to minimize spurious emissions. Since that decision was (hopefully) made with regard to the entire radio system, isn't that decision likely to be a good one? It was a good decision based on the information available at the time. Now that LP-Pan is created and a bit more IF output signal is needed, it has been determined that the small increment in IF output will not impact the original goal of minimizing the IF output. It's a potential production mod that Elecraft might even make. Your confidence in Elecraft is reinforced by this example. The K3 is extremely well-designed as a system component where there are countless other system components it might be connected with. Some system components such as LP-Pan didn't even exist when the K3 was released and there are far too many system components for Elecraft or anyone to fully validate. The fact that the K3 works so well with all these variables is evidence of exceptional design. 73, Ed - W0YK ___ 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] K3 Buffer Mod
Lyle Johnson wrote: Elecraft is well aware of N8LP's mod, Wayne saw no problems with it at first glance and is now considering whether to make it a production mod. Both N8LP and K8ZOA seem to feel it is not damaging the radio, etc. Remember to make the measurements Jack points out on his web page if you do the mod. This is to be sure the buffer transistor does not exceed its thermal ratings. Yes, here are the details: http://cliftonlaboratories.com/elecraft_k3_and_panadapters.htm#Alternative_to_increasing_K3_IF_sample_port_output ** If you make this modification, I suggest measuring the voltage across the new R9. Q10's drain current is set by a combination of the voltage drop across R9 and the individual characteristics of the J310 part in your K3. FETs have a notoriously wide part-to-part spread in parameters and it's possible that the J310 device in your K3 has parameters sufficiently far from the mean that Q10's power dissipation limits will be reached or exceeded. The surface mount J310 has a maximum power dissipation rating of 350 mw, and for reliability a safe operating value is 200 mw or so. Q10's current can be easily determined by measuring the voltage drop across R9. If changed to 49.9 ohms, Q10's drain current Id is 1000*Vs/50 (in milliamperes) where Vs is the voltage measured from ground to Q10's source pin. To calculate the power dissipated in Q10, measure its drain voltage. The power is then (Vd-Vs)*Id in milliwatts, where Id is in milliamperes. An example. After replacing R9 with a 49.9 ohm resistor, the following voltage readings are found: Vs = 2 volts, Vd = 12 volts. The idle current through Q10 is thus 2 / 49.9 = 40 mA. The power dissipated in Q10 is (12-2) * 40 = 400 milliwatts. This exceeds the J310's maximum permissible power dissipation and would not be a good design practice. ** In my unit the voltage across R9 was 460 mV, which resulted in 0.46/51 = 9 mA and power of 90 mW, well below the maximum rating of 350 mW and below Jack's recommendation of 200 mW. 73, Bill -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp741709p759959.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
I am scratching my head wondering whether any of this applies to the LP-PAN, or whether it is only relevant to other panadaptors such as the Softrock and the Z90. K8ZOA's web page (the same one everyone is quoting) says: I looked at two potential panadapters; a Softrock and my Z90. (Telepostinc's LP-PAN has a built-in amplifier to overcome the transfer gain problem.) and in the recommendations near the bottom of the page, refering to the mod, These steps are not necessary with an LP-PAN panadapter as it has a built-in isolation amplifier. That same web page also suggests that an alternative to the mod would be to use an external buffer amplifier. So, I have two questions: 1. Is the mod necessary with the LP-PAN, or is it only needed with other panadapters? That is, is the noise figure of the LP-PAN's internal amplifier sufficient, or is the mod to the K3 required to lift weak signals above the noise floor of the LP-PAN? 2. Would the external buffer amplifier solution be a viable alternative to the mod? 73, Rich VE3KI ___ 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] K3 Buffer Mod
Larry's LP-PAN uses my Z1 amplifier design in its front end, with a couple of modifications to provide variable gain. The AD8007 amplifier chip in both my Z1 and the LP-PAN is a decent amplifier with a respectable noise figure. If the K3's IF sample circuit had been built with closer to 0 dB transfer gain, then the composite noise figure would be closer to the K3's noise figure. To answer the two questions directly (I don't have an LP-PAN, so Larry might wish to modify my answers): 1. Is the mod necessary with the LP-PAN, or is it only needed with other panadapters? That is, is the noise figure of the LP-PAN's internal amplifier sufficient, or is the mod to the K3 required to lift weak signals above the noise floor of the LP-PAN? I believe you will see a small improvement in composite K3-LP-PAN noise figure if the changes are made to the K3's IF sample circuitry. However, I doubt that under most band conditions you will observe a difference as there is sufficient external noise to mask the improvement. 2. Would the external buffer amplifier solution be a viable alternative to the mod? Yes, I believe it is if you are using something other than the LP-PAN as the panadapter. Panadapters are not normally designed to be as sensitive as a receiver. There are many reasons for that that I won't bother to go over now. The consequence is that designers of receivers that provide a pan scope RF sample have the levels set so that there is at least a net 0 gain, and positive gains of 10 dB or more are not uncommon. I'm speaking mostly of commercial and military grade equipment, but my Kenwood TS-940 has reasonable transfer gain as well. Jack K8ZOA www.cliftonlaboratories.com Richard Ferch wrote: I am scratching my head wondering whether any of this applies to the LP-PAN, or whether it is only relevant to other panadaptors such as the Softrock and the Z90. K8ZOA's web page (the same one everyone is quoting) says: I looked at two potential panadapters; a Softrock and my Z90. (Telepostinc's LP-PAN has a built-in amplifier to overcome the transfer gain problem.) and in the recommendations near the bottom of the page, refering to the mod, These steps are not necessary with an LP-PAN panadapter as it has a built-in isolation amplifier. That same web page also suggests that an alternative to the mod would be to use an external buffer amplifier. So, I have two questions: 1. Is the mod necessary with the LP-PAN, or is it only needed with other panadapters? That is, is the noise figure of the LP-PAN's internal amplifier sufficient, or is the mod to the K3 required to lift weak signals above the noise floor of the LP-PAN? 2. Would the external buffer amplifier solution be a viable alternative to the mod? 73, Rich VE3KI ___ 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] K3 Buffer Mod
Thanks for the interesting info Chen. Your post did not make it to the list for some reason so I'm leaving it attached below for any (including Elecraft) that may be interested. 73, Bill W4ZV On Fri, Aug 22, 2008 at 12:31 PM, Kok Chen [EMAIL PROTECTED] wrote: All sound cards that are connected to a QSD-based SDR have an absolute noise floor. If a signal that is being converted is weaker than this A/D noise floor, it will not move the least significant bit of the A/D converter; i.e., the software demodulator receives no signal. Indeed, the signal needs to be a couple of bits stronger than the noise floor, or you are going to get unwanted spectral byproducts that degrades the demodulation capabilities of the SDR. Thus, you want the noise floor of the K3's I.F. output to be at least as strong as the noise floor of the SDR. If the K3's noise floor is stronger, you can always use a pad in between. It is only when the two noise floors are matched that you will get the maximum dynamic range out of an SDR based system. The only time you can use an A/D converter down to, and below, the least significant bit of the A/D is if the input noise to the A/D converter is Gaussian (i.e., there are no other strong signals anywhere in the passband). You will then be able to use noise linearization to obtain a perfectly undistorted spectrum. This is known as the Van Vleck theorem, which also appears in Probability books as the Arcsine law of joint Gaussian processes. However, you will need some software to apply a correction, plus you always lose 2.1 dB in recovered SNR. The noise linearization technique had been put to good use by Van Vleck in WWII radar and Sandy Weinreb's autocorrelation receiver in radio astronomy, but I am not sure it will work well in H.F. radios, and certainly not when listening to a pileup. 73, Chen, W7AY ___ 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] K3 Buffer Mod
I have addressed this on my reflector, but for the benefit of those on the Elecraft reflector... 95% of LP-PAN users will be happy with the NF and sensitivity without any modifications to the K3. On most bands, the resulting NF caused by the loss in the K3 buffer will be masked by atmospheric noise. On the higher bands, keeping the K3 preamp on will help a lot. This is usually OK at most locations because the K3 preamp is quite strong. The reason I came up with the mod is because a couple users were trying to use CW Skimmer for weak signal detection with LP-PAN feeding it. The mod improves the NF of the IF output by up to 10dB (K3 preamp off, somewhat less with the K3 preamp ON). Even though the NF of LP-PAN itself is quite good, it can't do anything to improve the system NF since it's downstream of the loss. My advice is to try it without modifying the K3 first. You will most likely be quite happy with the result. Be sure to read all the instructions before attempting the mod. It is comparable in complexity to the HAGC mod that Elecraft offers... but still requires reworking SMT parts. 73, Larry N8LP Jack Smith wrote: Larry's LP-PAN uses my Z1 amplifier design in its front end, with a couple of modifications to provide variable gain. The AD8007 amplifier chip in both my Z1 and the LP-PAN is a decent amplifier with a respectable noise figure. If the K3's IF sample circuit had been built with closer to 0 dB transfer gain, then the composite noise figure would be closer to the K3's noise figure. To answer the two questions directly (I don't have an LP-PAN, so Larry might wish to modify my answers): 1. Is the mod necessary with the LP-PAN, or is it only needed with other panadapters? That is, is the noise figure of the LP-PAN's internal amplifier sufficient, or is the mod to the K3 required to lift weak signals above the noise floor of the LP-PAN? I believe you will see a small improvement in composite K3-LP-PAN noise figure if the changes are made to the K3's IF sample circuitry. However, I doubt that under most band conditions you will observe a difference as there is sufficient external noise to mask the improvement. 2. Would the external buffer amplifier solution be a viable alternative to the mod? Yes, I believe it is if you are using something other than the LP-PAN as the panadapter. Panadapters are not normally designed to be as sensitive as a receiver. There are many reasons for that that I won't bother to go over now. The consequence is that designers of receivers that provide a pan scope RF sample have the levels set so that there is at least a net 0 gain, and positive gains of 10 dB or more are not uncommon. I'm speaking mostly of commercial and military grade equipment, but my Kenwood TS-940 has reasonable transfer gain as well. Jack K8ZOA www.cliftonlaboratories.com Richard Ferch wrote: I am scratching my head wondering whether any of this applies to the LP-PAN, or whether it is only relevant to other panadaptors such as the Softrock and the Z90. K8ZOA's web page (the same one everyone is quoting) says: I looked at two potential panadapters; a Softrock and my Z90. (Telepostinc's LP-PAN has a built-in amplifier to overcome the transfer gain problem.) and in the recommendations near the bottom of the page, refering to the mod, These steps are not necessary with an LP-PAN panadapter as it has a built-in isolation amplifier. That same web page also suggests that an alternative to the mod would be to use an external buffer amplifier. So, I have two questions: 1. Is the mod necessary with the LP-PAN, or is it only needed with other panadapters? That is, is the noise figure of the LP-PAN's internal amplifier sufficient, or is the mod to the K3 required to lift weak signals above the noise floor of the LP-PAN? 2. Would the external buffer amplifier solution be a viable alternative to the mod? 73, Rich VE3KI ___ 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] K3 Buffer Mod
Bill W4ZV wrote: Thinks of it this way...if you're trying to listen to an extremely weak signal, would you like a 17.7 dB attenuator between it and your ears? I don't think so. But this is not a 17.7db attenuator in the front end. The signal will have been amplified by the time it gets to this point. So the noise will be attenuated as well as the signal. Perhaps it won't be as sensitive, but the loss won't be as much as 17dB. I find it hard to accept your implication that Elecraft designed an IF output that is effectively useless. - Julian, G4ILO. K2 #392 K3 #222. http://www.g4ilo.com/ G4ILO's Shack http://www.ham-directory.com/ Ham Directoryhttp://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp759790p768378.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
Jerry, I do agree with you. There is a requirement for an isolation amplifier anyhow, so I do not understand why the -17.7 dB cannot be made up in the isolation amplifier if the device to be driven needs input at the same level as the antenna signal. Should Elecraft ever come out with a device (Panadapter?) that is designed to connect to the IF out at the level it currently is designed for, any K3 that has been modified will require that the modification be removed. 73, Don W3FPR Jerry Flanders wrote: Don Rasmussen wrote: I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. At 08:16 AM 8/22/2008, Bill W4ZV wrote: 17.7 dB transfer loss from RF IN to IF OUT is why... But isn't that just an engineering design decision made by the Elecraft team? Since that decision was (hopefully) made with regard to the entire radio system, isn't that decision likely to be a good one? As one data point, my K3 is not modified, yet the IF panadaptor works extremely well, and PowerSDR gives peak heights approximating the true signal strengths seen at the input of the K3. When I feed in a 1 uV signal from my KG-2 signal generator, I see a definite distinct peak on the panadaptor, and when I feed in a 50 uV (S9) signal, I see a large S9 signal on the panadaptor. I am a loss to understand why you guys are quarreling with the Elecraft design in this instance. I am beginning to suspect that it is simply because it does not agree with the usual designs provided by some military contractors who are probably using an _arbitrary_ standard anyway. I would think twice before possibly damaging my radio or lowering its resale value with non-factory authorized modifications. YMMV. Jerry W4UK ___ 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] K3 Buffer Mod
Date: Fri, 22 Aug 2008 16:50:46 -0400 From: Don Wilhelm [EMAIL PROTECTED] Should Elecraft ever come out with a device (Panadapter?) that is designed to connect to the IF out at the level it currently is designed for, any K3 that has been modified will require that the modification be removed. No, they're clever about things like that- unless there's a good reason not to, any device they would design would be able to cope with either signal level. Unless they decide the mod (or a version of it) has a distinct advantage, in which it will be blessed and incorporated into future production. 73, doug ___ 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] K3 Buffer Mod
Bill W4ZV wrote: Think of it this way...if you're trying to listen to an extremely weak signal, would you like a 17.7 dB attenuator between it and your ears? I don't think so. Julian, G4ILO wrote: But this is not a 17.7db attenuator in the front end. The signal will have been amplified by the time it gets to this point. So the noise will be attenuated as well as the signal. Perhaps it won't be as sensitive, but the loss won't be as much as 17dB. I find it hard to accept your implication that Elecraft designed an IF output that is effectively useless. Who said it's effectively useless? Please read the following from N8LP: http://n2.nabble.com/K3-Buffer-Mod-tt741709.html#a760307 In particular, his last sentence below: The reason I came up with the mod is because a couple users were trying to use CW Skimmer for weak signal detection with LP-PAN feeding it. The mod improves the NF of the IF output by up to 10dB (K3 preamp off, somewhat less with the K3 preamp ON). Even though the NF of LP-PAN itself is quite good, it can't do anything to improve the system NF since it's downstream of the loss. If you're using the K3's IF OUT LP-PAN as a simple panadaptor, it's probably OK as is. If you're trying to use a waterfall in PowerSDR, Winrad or CW Skimmer to detect noise floor signals, it's not. Even a $15 Softrock will do a better job of the latter unless the mod is installed. I'm quite happy with N8LP's mod, but let's not bury our heads in the sand and say it's unnecessary. That reminds me of what I'd expect from Yaesu or Icom... 73, Bill -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp759790p777143.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
I added a section to the instructions for the mod this morning that echo Jack's suggestion to check the dissipation of Q10. Because of the great variability of specs with the J310, it is a good idea to check it. Jack's example is not representative of any actual measurements, but rather just an example of how to calculate the dissipation. In my case, I found a calculated dissipation of about 125mW... a quite safe value. My original SPICE simulation predicted 180mW. The device is rated at 350mW, and my goal was to keep dissipation to half that value. Larry N8LP Message: 24 Date: Fri, 22 Aug 2008 09:13:40 -0700 (PDT) From: Bill W4ZV [EMAIL PROTECTED] Subject: Re: [Elecraft] K3 Buffer Mod To: elecraft@mailman.qth.net Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii Lyle Johnson wrote: Elecraft is well aware of N8LP's mod, Wayne saw no problems with it at first glance and is now considering whether to make it a production mod. Both N8LP and K8ZOA seem to feel it is not damaging the radio, etc. Remember to make the measurements Jack points out on his web page if you do the mod. This is to be sure the buffer transistor does not exceed its thermal ratings. Yes, here are the details: http://cliftonlaboratories.com/elecraft_k3_and_panadapters.htm#Alternative_to_increasing_K3_IF_sample_port_output ** If you make this modification, I suggest measuring the voltage across the new R9. Q10's drain current is set by a combination of the voltage drop across R9 and the individual characteristics of the J310 part in your K3. FETs have a notoriously wide part-to-part spread in parameters and it's possible that the J310 device in your K3 has parameters sufficiently far from the mean that Q10's power dissipation limits will be reached or exceeded. The surface mount J310 has a maximum power dissipation rating of 350 mw, and for reliability a safe operating value is 200 mw or so. Q10's current can be easily determined by measuring the voltage drop across R9. If changed to 49.9 ohms, Q10's drain current Id is 1000*Vs/50 (in milliamperes) where Vs is the voltage measured from ground to Q10's source pin. To calculate the power dissipated in Q10, measure its drain voltage. The power is then (Vd-Vs)*Id in milliwatts, where Id is in milliamperes. An example. After replacing R9 with a 49.9 ohm resistor, the following voltage readings are found: Vs = 2 volts, Vd = 12 volts. The idle current through Q10 is thus 2 / 49.9 = 40 mA. The power dissipated in Q10 is (12-2) * 40 = 400 milliwatts. This exceeds the J310's maximum permissible power dissipation and would not be a good design practice. ** In my unit the voltage across R9 was 460 mV, which resulted in 0.46/51 = 9 mA and power of 90 mW, well below the maximum rating of 350 mW and below Jack's recommendation of 200 mW. 73, Bill ___ 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] K3 Buffer Mod
The gain can easily be made up, and is, but NF can not be made up in later stages once it is set in an earlier one. Anything connected to the IF port can only increase NF, no matter how quiet it is or how much gain it has. The easiest way to improve composite NF would be to add a strong, low noise preamp with adequate gain AHEAD of the K3, but that would compromise IMD. There would be no reason to un-modify a K3 to work with any kind of panadapter connected to the IF port. 73, Larry N8LP Message: 37 Date: Fri, 22 Aug 2008 16:50:46 -0400 From: Don Wilhelm [EMAIL PROTECTED] Subject: Re: [Elecraft] K3 Buffer Mod To: Jerry Flanders [EMAIL PROTECTED] Cc: elecraft@mailman.qth.net Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=ISO-8859-1; format=flowed Jerry, I do agree with you. There is a requirement for an isolation amplifier anyhow, so I do not understand why the -17.7 dB cannot be made up in the isolation amplifier if the device to be driven needs input at the same level as the antenna signal. Should Elecraft ever come out with a device (Panadapter?) that is designed to connect to the IF out at the level it currently is designed for, any K3 that has been modified will require that the modification be removed. 73, Don W3FPR ___ 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] K3 Buffer Mod
I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. I have never attempted as delicate a procedure as this. I am soliciting suggestions on how to do this without damaging the rf board. Jim K7EG ___ 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] K3 Buffer Mod
I have never attempted as delicate a procedure as this. I am soliciting suggestions on how to do this without damaging the rf board. I always use two (2) small temp-controlled soldering irons (Hakko 936). The idea is to heat both ends simultaneously to melt the solder without dwelling too long on the board. The parts likely have a small amount of adhesive under them so once the solder is melted, I push one end with a soldering iron while holding the other end still. This breaks the part free from the adhesive. Be certain the soldering irons aren't set too hot. 650 F is about right, 700F is probably OK, higher is a Bad Idea. There is little thermal mass here. The worst problem will be heat flow from the grounded end of one of the two resistors. Or, you may have an iron with a wide enough tip to heat both ends of the part - that will work too, just keep the temperature under control :-) I haven't had breakfast yet so I'm not thinking clearly; the RF board you damage maybe your own; YMMV, ... 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] K3 Buffer Mod
Jim A Hakko tweezer handpiece makes removing surface mount parts easy, but it's a pricey solution for just a couple parts. Depending on the tools you have and the size of the part, you might consider using a pair of small cutters to snip the resistors in half before removing it. Then you can use a standard soldering iron and solder wick to clean the pads up. You're not trying to salvage the part, of course. Surface mount resistors are made with a ceramic substrate so they shatter easily. That's what you want to do--shatter the ceramic so that you can work on each end individually. The practicality of this approach depends on the part size, how much free room you have to access it and the size of your cutters. It works well for 1206 parts and OK for 805 size resistors, but I have not tried it with smaller devices. If there's a risk of damaging other components or a PCB trace, of course, don't use this approach. Jack Jim Denneny wrote: I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. I have never attempted as delicate a procedure as this. I am soliciting suggestions on how to do this without damaging the rf board. Jim K7EG ___ 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] K3 Buffer Mod
At 09:48 AM 8/21/2008, Jim Denneny wrote... I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. Chip-quick ( http://www.chipquikinc.com/newsletters/cq_new_june_2004.htm ) is great for doing SMT rework. It's a low melting temperature alloy, which you use like solder. It mixes with the existing solder to make device removal easy. It doesn't take much. Without a rework station, it's about the only thing you can use for larger devices. If you were experienced in working with SMT, then it might be overkill for replacing just a resistor. But even if you've done SMT before, there's still the danger of lifting a pad when using just a soldering iron. Good stuff if you want to do it yourself with minimal risk to an expensive board. For soldering the new component, I just make sure the pads are lightly tinned, hold the component in place with a toothpick, and lightly touch each joint with the iron. ___ 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] K3 Buffer Mod
James Denneny wrote: I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. This is about the simplest SMD work one can do, but I would *strongly* recommend you find a scrap SMD board and practice removing and soldering a few resistors first. Almost any scrap board (like an old modem) should have some resistors. I've not had any problems removing components like Rs and Cs using a single Circuit Specialists clone of the Hakko 936 with a 1.6mm chisel tip at 700 degrees. I found the resistors easily slide off after alternately heating each side, but you definitely should practice first. -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp738458p740658.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
G'day, What is this mod? regards, Mike VP8NO - Original Message - From: Bill W4ZV [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Thursday, August 21, 2008 12:51 PM Subject: Re: [Elecraft] K3 Buffer Mod | | | | James Denneny wrote: | | I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. | It involves exchanging two, extremely small, surface-mount resistors. | | | This is about the simplest SMD work one can do, but I would *strongly* | recommend you find a scrap SMD board and practice removing and soldering a | few resistors first. Almost any scrap board (like an old modem) should have | some resistors. I've not had any problems removing components like Rs and | Cs using a single Circuit Specialists clone of the Hakko 936 with a 1.6mm | chisel tip at 700 degrees. I found the resistors easily slide off after | alternately heating each side, but you definitely should practice first. | | -- | View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp738458p740658.html | Sent from the Elecraft mailing list archive at Nabble.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 | | No virus found in this incoming message. | Checked by AVG - http://www.avg.com | Version: 8.0.138 / Virus Database: 270.6.6/1625 - Release Date: 21/08/2008 06:04 | | | ___ 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] K3 Buffer Mod
At 09:48 AM 8/21/2008, Jim Denneny wrote... I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. Chip-quick ( http://www.chipquikinc.com/newsletters/cq_new_june_2004.htm ) is great for doing SMT rework. It's a low melting temperature alloy, which you use like solder. It mixes with the existing solder to make device removal easy. It doesn't take much. Although I am a big fan of ChipQuik you should try it on an old PC board before you try it on something that might break your heart if you fail. ChipQuik can send a part flying (along with a trail of molten ChipQuik) if the part has been tacked down with an adhesive and requires a little pressure. Once you get the hang of it, on a multipin IC, it can be a life saver. I don't think I would use it on a resistor or cap though. I would go with the single iron back and forth or the two iron method. Tom, AK2B -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp738458p740797.html Sent from the Elecraft mailing list archive at Nabble.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] K3 Buffer Mod
There's one easy trick I learned a while back. Actually add solder to each end of the R or C to be removed. This creates a larger thermal mass that doesn't cool and harden as quickly, and gives you time to get the other end melted too. Then the part slides right off. As has been recommended before, practice first on some junk pc board with SMD parts on it. Really easy technique. Good luck and 73 Bob N6WG - Original Message - From: Tom AK2B [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Thursday, August 21, 2008 10:43 AM Subject: Re: [Elecraft] K3 Buffer Mod At 09:48 AM 8/21/2008, Jim Denneny wrote... I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. Chip-quick ( http://www.chipquikinc.com/newsletters/cq_new_june_2004.htm ) is great for doing SMT rework. It's a low melting temperature alloy, which you use like solder. It mixes with the existing solder to make device removal easy. It doesn't take much. Although I am a big fan of ChipQuik you should try it on an old PC board before you try it on something that might break your heart if you fail. ChipQuik can send a part flying (along with a trail of molten ChipQuik) if the part has been tacked down with an adhesive and requires a little pressure. Once you get the hang of it, on a multipin IC, it can be a life saver. I don't think I would use it on a resistor or cap though. I would go with the single iron back and forth or the two iron method. Tom, AK2B -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp738458p740797.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] K3 Buffer Mod
Should I expect any negative impacts if I used regular resistors in place of SM resistors for this mod? N2TK, Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bill W4ZV Sent: Thursday, August 21, 2008 12:52 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Buffer Mod James Denneny wrote: I am about to attempt the N8LP K3 Buffer Mod for improved RX performance. It involves exchanging two, extremely small, surface-mount resistors. This is about the simplest SMD work one can do, but I would *strongly* recommend you find a scrap SMD board and practice removing and soldering a few resistors first. Almost any scrap board (like an old modem) should have some resistors. I've not had any problems removing components like Rs and Cs using a single Circuit Specialists clone of the Hakko 936 with a 1.6mm chisel tip at 700 degrees. I found the resistors easily slide off after alternately heating each side, but you definitely should practice first. -- View this message in context: http://n2.nabble.com/K3-Buffer-Mod-tp738458p740658.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] K3 Buffer Mod
Tony, I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. IMO (in my opinion) you don't work with SMD on K3, they fly around like little fleas even if you use a pair of 15w irons to remove them. They are just that small. But you can get them off without any major damage, find them, and carefully replace them - *when necessary*. YMMV... de wb8yqj Previous message: [Elecraft] K3 Buffer Mod Next message: [Elecraft] K2/100 LOCKUP THOUGHTS? Should I expect any negative impacts if I used regular resistors in place of SM resistors for this mod? N2TK, Tony ___ 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] K3 Buffer Mod
It sounds like Tony should leave the K3 as is. Dont screw it up unless your qualified to make the mods. Jim K4JAF - Original Message - From: Don Rasmussen [EMAIL PROTECTED] To: elecraft@mailman.qth.net Sent: Thursday, August 21, 2008 7:06 PM Subject: [Elecraft] K3 Buffer Mod Tony, I have the LP-Pan with recommended Creative Labs E-MU 0202 and find this to be optimal, I mean no reason to make a mod of any type to K3. If someone told you that this must be done, I'd want to see why with my own eyes before doing this job. IMO (in my opinion) you don't work with SMD on K3, they fly around like little fleas even if you use a pair of 15w irons to remove them. They are just that small. But you can get them off without any major damage, find them, and carefully replace them - *when necessary*. YMMV... de wb8yqj Previous message: [Elecraft] K3 Buffer Mod Next message: [Elecraft] K2/100 LOCKUP THOUGHTS? Should I expect any negative impacts if I used regular resistors in place of SM resistors for this mod? N2TK, Tony ___ 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
