[Elecraft] K3/100 and the PSU
Everyone knows it is important for the K3/100 to receive a solid DC supply. If the supply drops significantly when high current is drawn several effects may occur: 1 - The Transmitted signal becomes wider than it should be 2 - The power control loop is upset leading to unstable output power 3 - In severe cases the radio might shut down, or engage sulk mode. Of course this does not apply to us, we are all experienced constructors and never make mistakes when wiring up our shacks. Like many people I run my K3 from a 13.8V DC supply that also supplies other items, in my case XV transverters, an LP100, an LDG ATU etc. This supply is very good (tnx BNOS, 1980s) and only varies by a few 10s of mV between no and full load. Originally when installing my K3/10 I used the supplied DC cable via a powerpole distribution board with an appropriate fuse. In fact this particular board had two fuses, one 30A one at the input and one at the output plus around 1 metre of thick cable to the supply. This worked fine. Later I upgraded to the 100W KPA3, and of course changed the fuse in the distribution board. The DC voltage drop according to the K3 at 20A was over a volt, much no doubt due to the fuses and extra connections through the distribution board. A 1 volt drop is not a problem for the K3 but will cause more IMDs on SSB. I now connect the K3 directly to the PSU with as short a DC cable as is practical. It would be even better to use voltage sensing so the supply is regulated at the K3 end of the cable. Mike -- View this message in context: http://n2.nabble.com/K3-100-and-the-PSU-tp2223048p2223048.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] K3/100 and the PSU
Yes I´m beginning to think that K3 is more sensitive to PS then other radios, right now it looks that way. Then this should be in the manual!!! What happens is if I have a bad signal on the bands I will together with Elecraft get a bad reputation. I will of course tell everyone what I´m running and do have it operating exactly according to the manual. If this PS deal is the case with the K3 I quite understand and it´s no problem to me what so ever but it should be in the operating manual. Every user of a K3 should not need to be a super engineer and have to figure out things like this them self. This morning I increased PS voltage to 14.6V (14.2) under load, I was at 13.9V (13.5 load) before, I could see a slight improvement in IMD (1-2 dB). I am using the supplied high performance cable from Elecraft and IMO it does not have enough Cu area. Next But if Elecraft supplies it and it´s not good enough, what can I say? / Jim SM2EKM -- AD6XY wrote: Everyone knows it is important for the K3/100 to receive a solid DC supply. If the supply drops significantly when high current is drawn several effects may occur: 1 - The Transmitted signal becomes wider than it should be 2 - The power control loop is upset leading to unstable output power 3 - In severe cases the radio might shut down, or engage sulk mode. Of course this does not apply to us, we are all experienced constructors and never make mistakes when wiring up our shacks. Like many people I run my K3 from a 13.8V DC supply that also supplies other items, in my case XV transverters, an LP100, an LDG ATU etc. This supply is very good (tnx BNOS, 1980s) and only varies by a few 10s of mV between no and full load. Originally when installing my K3/10 I used the supplied DC cable via a powerpole distribution board with an appropriate fuse. In fact this particular board had two fuses, one 30A one at the input and one at the output plus around 1 metre of thick cable to the supply. This worked fine. Later I upgraded to the 100W KPA3, and of course changed the fuse in the distribution board. The DC voltage drop according to the K3 at 20A was over a volt, much no doubt due to the fuses and extra connections through the distribution board. A 1 volt drop is not a problem for the K3 but will cause more IMDs on SSB. I now connect the K3 directly to the PSU with as short a DC cable as is practical. It would be even better to use voltage sensing so the supply is regulated at the K3 end of the cable. Mike ___ 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] K3/100 and the PSU
As a good engineer I should have stated what I measure with, sorry. Normal 2-tone test, and a HP 8591E spectrum analyzer. Normally I like to do it with speech, i e fully modulate the radio and look at the sample 5 kHz on each side. That is IMO better then a 2-tone test since it will tell you more. And by the way, I did NOT say 2 dB, read below. As an anecdote you can look at this: http://sk3w.se/sm2ekm/view_photo.php?set_albumName=SM2EKM-picturesid=FT_1000D http://sk3w.se/sm2ekm/view_photo.php?set_albumName=SM2EKM-picturesid=KWM_2 We can see that the Collins KWM-2 is ca 10 dB better on adjacent channel compared to Yaesu FT-1000D. The FT-1000D is one of the best modern things around when it´s up to TX IMD. Anything else I have measured is worse then the FT-1000D. Receivers has been getting better but not transmitters that is the bottom line. / Jim SM2EKM - m.j.wil...@rl.ac.uk wrote: I am sure PSU regulation affects all other 12V radios in exactly the same way. The only reason Elecraft users will see it more is because they are more discerning. How do you measure IMDs? 2dB is a worthwhile improvement. It would be interesting to try a better supply cable and also to see if the 20A cutout has any effect. Mike Jan Erik Holm wrote: Yes I´m beginning to think that K3 is more sensitive to PS then other radios, right now it looks that way. Then this should be in the manual!!! What happens is if I have a bad signal on the bands I will together with Elecraft get a bad reputation. I will of course tell everyone what I´m running and do have it operating exactly according to the manual. If this PS deal is the case with the K3 I quite understand and it´s no problem to me what so ever but it should be in the operating manual. Every user of a K3 should not need to be a super engineer and have to figure out things like this them self. This morning I increased PS voltage to 14.6V (14.2) under load, I was at 13.9V (13.5 load) before, I could see a slight improvement in IMD (1-2 dB). I am using the supplied high performance cable from Elecraft and IMO it does not have enough Cu area. Next But if Elecraft supplies it and it´s not good enough, what can I say? / Jim SM2EKM -- AD6XY wrote: Everyone knows it is important for the K3/100 to receive a solid DC supply. If the supply drops significantly when high current is drawn several effects may occur: 1 - The Transmitted signal becomes wider than it should be 2 - The power control loop is upset leading to unstable output power 3 - In severe cases the radio might shut down, or engage sulk mode. Of course this does not apply to us, we are all experienced constructors and never make mistakes when wiring up our shacks. Like many people I run my K3 from a 13.8V DC supply that also supplies other items, in my case XV transverters, an LP100, an LDG ATU etc. This supply is very good (tnx BNOS, 1980s) and only varies by a few 10s of mV between no and full load. Originally when installing my K3/10 I used the supplied DC cable via a powerpole distribution board with an appropriate fuse. In fact this particular board had two fuses, one 30A one at the input and one at the output plus around 1 metre of thick cable to the supply. This worked fine. Later I upgraded to the 100W KPA3, and of course changed the fuse in the distribution board. The DC voltage drop according to the K3 at 20A was over a volt, much no doubt due to the fuses and extra connections through the distribution board. A 1 volt drop is not a problem for the K3 but will cause more IMDs on SSB. I now connect the K3 directly to the PSU with as short a DC cable as is practical. It would be even better to use voltage sensing so the supply is regulated at the K3 end of the cable. Mike ___ 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] K3/100 and the PSU
I used the included power cable and did notice a drop in the voltage of about a volt. I had bought a 35 amp, 25 amp continuous Astron power supply which has variable voltage but does not include a remote probe as the one I made from the ARRL handbook offered. The probe was used to ID voltage drop and the PS responded by upping the voltage as needed so 13.8 would be at the rig at all times. Using that probe with my old TR7 kept the voltage dead on at the rig. I was saddened to have left that in Indiana as a gift to a friend for the PS components were made from an old Wang computer I canabalized in the 80's and I designed it for an easy 80 amps and it weighed over 100 pounds and was on casters. It was too much to move and is in use today by my friend but I digress; I felt the best option with the K3 and the Astron VS35M was to use a different power cable so I cut the cable aproximately 5 from the Power Pole and soldered that short end to an 8 gauge cable made of very fine wire which I bought from Home Depot. This was part of heavy cable at about $5/foot with four conductors and a heavy neoprene outer jacket. I stripped the jacket, used two of the connectors and attached a 4' length to the Astron k3. From the K3 internal volt meter it reads: 14.0V at idle: At 25W the drop is .2 = 13.8 At 50W the drop is .3 = 13.7 At 75W the drop is .3 = 13.7 At 100W the drop is .4 = 13.6 at 120W the drop is .4 = 13.6 Not as regulated at the rig as my old homebrew PS but certainly a very little voltage drop. When running the amp I never use more than 50W drive so I'm content. One caveat is I felt the need to devise a mount to keep the power cord from moving around behind the radio. I know the PowerPoles are loved by many but I see these smaller variety as a weak point and don't much like them attached to the rig. The old TenTec attachments were not as sexy as these PowerPoles but I felt they had more heft and I didn't feel concern that someday the internal soldering would come loose from repeated motion as the rig is located from one site to another. Perhaps if the next larger size of PowerPole were utilized I would feel it more sturdy? 73, GAry KA1J ___ 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] K3/100 and the PSU
The old TenTec attachments were not as sexy as these PowerPoles but I felt they had more heft and I didn't feel concern that someday the internal soldering would come loose from repeated motion as the rig is located from one site to another. Interesting. At least on the newer T-T rigs, the power connectors have been a source of loud and continuous gnashing of teeth for many. If one uses the proper crimp tool on the PowerPoles AND flows solder into the crimped joint (sort of like wearing both a belt and suspenders), nothing much should come loose with a whole lot of wiggling about. I don't have a love affair with Anderson connectors, but I use them on all the DC distribution in my station, and have yet to have any sort of problem. Perhaps we could convince Elecraft to put big split bolts on the radio for power connections. That would also have the side effect of requiring a larger cabinet with space for more knobs, which would please a lot of folks, too :-) Grant/NQ5T ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K3/100 and the PSU
Gary You could wire the power cable direct to the pcb inside the K3, that would further reduce your losses and avoid connector damage/intermittence if it's being wiggled a lot. David G3UNA - Original Message - From: Gary Smith g...@doctorgary.net To: Elecraft@mailman.qth.net Sent: Tuesday, January 27, 2009 4:14 PM Subject: Re: [Elecraft] K3/100 and the PSU I used the included power cable and did notice a drop in the voltage of about a volt. I had bought a 35 amp, 25 amp continuous Astron power supply which has variable voltage but does not include a remote probe as the one I made from the ARRL handbook offered. The probe was used to ID voltage drop and the PS responded by upping the voltage as needed so 13.8 would be at the rig at all times. Using that probe with my old TR7 kept the voltage dead on at the rig. I was saddened to have left that in Indiana as a gift to a friend for the PS components were made from an old Wang computer I canabalized in the 80's and I designed it for an easy 80 amps and it weighed over 100 pounds and was on casters. It was too much to move and is in use today by my friend but I digress; I felt the best option with the K3 and the Astron VS35M was to use a different power cable so I cut the cable aproximately 5 from the Power Pole and soldered that short end to an 8 gauge cable made of very fine wire which I bought from Home Depot. This was part of heavy cable at about $5/foot with four conductors and a heavy neoprene outer jacket. I stripped the jacket, used two of the connectors and attached a 4' length to the Astron k3. From the K3 internal volt meter it reads: 14.0V at idle: At 25W the drop is .2 = 13.8 At 50W the drop is .3 = 13.7 At 75W the drop is .3 = 13.7 At 100W the drop is .4 = 13.6 at 120W the drop is .4 = 13.6 Not as regulated at the rig as my old homebrew PS but certainly a very little voltage drop. When running the amp I never use more than 50W drive so I'm content. One caveat is I felt the need to devise a mount to keep the power cord from moving around behind the radio. I know the PowerPoles are loved by many but I see these smaller variety as a weak point and don't much like them attached to the rig. The old TenTec attachments were not as sexy as these PowerPoles but I felt they had more heft and I didn't feel concern that someday the internal soldering would come loose from repeated motion as the rig is located from one site to another. Perhaps if the next larger size of PowerPole were utilized I would feel it more sturdy? 73, GAry KA1J ___ 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] K3/100 and the PSU (and Power Pole Repair)
I recently used a heavy guage cable (#8 stranded, I believe) between the K3 and PS in a portable operation. The extra stiffness of the cable caused a strain that fractured the plastic shell on the positive Power Pole connector in the K3. So, I agree that some sort of strain relief is in order if larger/stiffer cable is used. Perhaps the pig-tail mention earlier is a reasonable approach. Fortunately, I was able to replace the Power Pole plastic shells without disassembling the K3. It required: 1) removing both the positive and negative shells using a small tool to lift the metal connector blades inside, 2) mating a new pair of connector, 3) scraping off a small protusion on the positive connector to allow the assembly to fit in the rear panel opening, and 4) sliding the assembly over the connector blades. Perhaps this will help if someone else encounters this problem. Chuck, AE4CW Grant Youngman wrote: The old TenTec attachments were not as sexy as these PowerPoles but I felt they had more heft and I didn't feel concern that someday the internal soldering would come loose from repeated motion as the rig is located from one site to another. Interesting. At least on the newer T-T rigs, the power connectors have been a source of loud and continuous gnashing of teeth for many. If one uses the proper crimp tool on the PowerPoles AND flows solder into the crimped joint (sort of like wearing both a belt and suspenders), nothing much should come loose with a whole lot of wiggling about. I don't have a love affair with Anderson connectors, but I use them on all the DC distribution in my station, and have yet to have any sort of problem. Perhaps we could convince Elecraft to put big split bolts on the radio for power connections. That would also have the side effect of requiring a larger cabinet with space for more knobs, which would please a lot of folks, too :-) Grant/NQ5T ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com -- View this message in context: http://n2.nabble.com/K3-100-and-the-PSU-tp2223048p2227563.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] K3/100 and the PSU (and Power Pole Repair)
On Tue, 27 Jan 2009 11:00:10 -0800 (PST), you wrote: I recently used a heavy guage cable (#8 stranded, I believe) between the K3 and PS in a portable operation. The extra stiffness of the cable caused a strain that fractured the plastic shell on the positive Power Pole connector in the K3. So, I agree that some sort of strain relief is in order if larger/stiffer cable is used. Perhaps the pig-tail mention earlier is a reasonable approach. Fortunately, I was able to replace the Power Pole plastic shells without disassembling the K3. It required: 1) removing both the positive and negative shells using a small tool to lift the metal connector blades inside, 2) mating a new pair of connector, 3) scraping off a small protusion on the positive connector to allow the assembly to fit in the rear panel opening, and 4) sliding the assembly over the connector blades. Perhaps this will help if someone else encounters this problem. Chuck, AE4CW Chuck and others, I have found that when you want larger cabling like #8 and above, the auto supply store is the best place to get flexible cables. The copper in these cables is ver fine, almost like hair. I'm feeding my two TE Systems amps (2 and 6m) with 04 battery cables from my 100 amp supply. The cables are not stiff. That would be over-kill for the K3, but these two amps draw 50 amps each at full power, and no, I don't run both at the same time ;o) Tom, N5GE http://www.n5ge.com http://www.swotrc.net [snip] ___ 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] K3/100 and the PSU
Jack, I built the supply around 1992 had the parts for a few years from before. It really was the ultimate PS I could vary the voltage from around 5V up to 15V. it has a crowbar circuit and the remote sensing unit and well, I really went overboard making it (my transformer weighed at least 80 pounds and the heatsink was liberated from the Navy) but it worked exactly as planned. I digress... I just looked in my library and if you have the 1984 ARRL handbook, you'll find the schematic I started with on page 5-19 under the heading A 300- to 400-Watt 12 volt supply. The 84 handbook has a blue cover. I remember the one I used had a gray cover so this schematic is in several handbooks. It was not in the 78 handbook though. I just don't have the parts any more or I would have built this instead of buying this new Astron for the K3. The Astron is an excellent supply (albeit sans remote sensor), I just like making things myself. Once the warranty is up on the Astron, I will likely piggyback a remote sensor in it, that was a truly nice feature. Gary KA1J Hi Gary, I like your idea of the remote sense for your Astron. Can you send me a reference for the article in the Handbook? I just looked through the 2008 Hanbook in the power supply section and did not see same. 73 and thank you, Jack, W3TMZ - Original Message - From: Gary Smith g...@doctorgary.net To: Elecraft@mailman.qth.net Sent: Tuesday, January 27, 2009 11:14 AM Subject: Re: [Elecraft] K3/100 and the PSU I used the included power cable and did notice a drop in the voltage of about a volt. I had bought a 35 amp, 25 amp continuous Astron power supply which has variable voltage but does not include a remote probe as the one I made from the ARRL handbook offered. The probe was used to ID voltage drop and the PS responded by upping the voltage as needed so 13.8 would be at the rig at all times. Using that probe with my old TR7 kept the voltage dead on at the rig. I was saddened to have left that in Indiana as a gift to a friend for the PS components were made from an old Wang computer I canabalized in the 80's and I designed it for an easy 80 amps and it weighed over 100 pounds and was on casters. It was too much to move and is in use today by my friend but I digress; I felt the best option with the K3 and the Astron VS35M was to use a different power cable so I cut the cable aproximately 5 from the Power Pole and soldered that short end to an 8 gauge cable made of very fine wire which I bought from Home Depot. This was part of heavy cable at about $5/foot with four conductors and a heavy neoprene outer jacket. I stripped the jacket, used two of the connectors and attached a 4' length to the Astron k3. From the K3 internal volt meter it reads: 14.0V at idle: At 25W the drop is .2 = 13.8 At 50W the drop is .3 = 13.7 At 75W the drop is .3 = 13.7 At 100W the drop is .4 = 13.6 at 120W the drop is .4 = 13.6 Not as regulated at the rig as my old homebrew PS but certainly a very little voltage drop. When running the amp I never use more than 50W drive so I'm content. One caveat is I felt the need to devise a mount to keep the power cord from moving around behind the radio. I know the PowerPoles are loved by many but I see these smaller variety as a weak point and don't much like them attached to the rig. The old TenTec attachments were not as sexy as these PowerPoles but I felt they had more heft and I didn't feel concern that someday the internal soldering would come loose from repeated motion as the rig is located from one site to another. Perhaps if the next larger size of PowerPole were utilized I would feel it more sturdy? 73, GAry KA1J ___ 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
