K3 Power Supply Question
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Hi All -
I’ve been powering my station for anywhere from 7 - 9 years (can’t recall exactly how long!) with an MFJ4245MV switching power supply. I use it in conjunction with a 72 watt GE solar panel, 110 Ah AGM battery, ProStar charge controller, N8XJK Boost Regulator, and a KI0BK Low Loss PowerGate. All cables have been fitted with multiple mix 31 ferrite dounts with multiple wraps - I’ve got pretty much NO RF hash on any of the HF bands on the K3 or my KX3. All the above power equipment feeds into a Rig Runner 4008. Anderson PowerPole connectors connect to as short as possible #12 cable to several devices: K3, P3, KX3, PX3, KXPA100, and a home brew W6PQL 2 meter all mode amp. Haven’t had any issues with the above configuration. Until today, when I happened to punch the K3 DISP button, changing it from reading my VFO B frequency to the other various bits of information. One of them was the rig voltage. Sitting there on 17 meters in CW mode receive it was showing a nice 13.8V. Cool. I hit the key and - wait a minute…… it dropped way down to 12.4v. Huh - not so cool. My first thought was that the Boost Regulator was not doing it’s job. But I decided to start trouble shooring at ground zero - the MFJ 4245. I disconnected it from the Power Gate and ran it directly to the K3. Key up = 13.8V. Key down = 12.0V. Yikes! I think (IMHO) calling this poor regulation (15%) would be a gross understatement. Am I wrong for expecting a desk power supply to do better than this? I had purchased this 4245 years ago because the price was right AND that it can run on 117 or 220 volts. At one time I had been contemplating a move to the Philippines and a 220v supply would be needed. By the way, nothing else running here in the shack other than a computer which was in sleep mode anyway, so line voltage sag likely is not the issue. So, if this this a common problem with the MFJ stuff, what other 25+ amp supplies are folks using with their K3’s that have better regulation than 15%? Jim / W6JHB ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Jim,
Get your DMM out and make the same measurement at the power supply terminals. If you see a substantial voltage sag during transmit there, you can blame the power supply. But if the voltage stays close to constant, the problem is voltage drop in the power cabling. The RigRunner will contribute some drop due to the extra contact points and even #12 or #10 wire has some resistance. If the power supply is good, run a power cable direct from the power supply to the K3 and run another power cable to the rigrunner. Run the accessories in the shack from the rigrunner. 73, Don W3FPR On 3/9/2017 8:09 PM, James Bennett wrote: > Hi All - > > Haven’t had any issues with the above configuration. Until today, when I happened to punch the K3 DISP button, changing it from reading my VFO B frequency to the other various bits of information. One of them was the rig voltage. Sitting there on 17 meters in CW mode receive it was showing a nice 13.8V. Cool. I hit the key and - wait a minute…… it dropped way down to 12.4v. Huh - not so cool. My first thought was that the Boost Regulator was not doing it’s job. But I decided to start trouble shooring at ground zero - the MFJ 4245. I disconnected it from the Power Gate and ran it directly to the K3. Key up = 13.8V. Key down = 12.0V. Yikes! I think (IMHO) calling this poor regulation (15%) would be a gross understatement. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: K3 Power Supply Question
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In reply to this post by James Bennett
I run an Astron 50 amp linear supply and a 4' cord between it and the K2
I see .6 of a volt drop on keydown at 100 watts From: James Bennett <[hidden email]> To: Elecraft Reflector Reflector <[hidden email]> Sent: Thursday, March 9, 2017 8:09 PM Subject: [Elecraft] K3 Power Supply Question Hi All - I’ve been powering my station for anywhere from 7 - 9 years (can’t recall exactly how long!) with an MFJ4245MV switching power supply. I use it in conjunction with a 72 watt GE solar panel, 110 Ah AGM battery, ProStar charge controller, N8XJK Boost Regulator, and a KI0BK Low Loss PowerGate. All cables have been fitted with multiple mix 31 ferrite dounts with multiple wraps - I’ve got pretty much NO RF hash on any of the HF bands on the K3 or my KX3. All the above power equipment feeds into a Rig Runner 4008. Anderson PowerPole connectors connect to as short as possible #12 cable to several devices: K3, P3, KX3, PX3, KXPA100, and a home brew W6PQL 2 meter all mode amp. Haven’t had any issues with the above configuration. Until today, when I happened to punch the K3 DISP button, changing it from reading my VFO B frequency to the other various bits of information. One of them was the rig voltage. Sitting there on 17 meters in CW mode receive it was showing a nice 13.8V. Cool. I hit the key and - wait a minute…… it dropped way down to 12.4v. Huh - not so cool. My first thought was that the Boost Regulator was not doing it’s job. But I decided to start trouble shooring at ground zero - the MFJ 4245. I disconnected it from the Power Gate and ran it directly to the K3. Key up = 13.8V. Key down = 12.0V. Yikes! I think (IMHO) calling this poor regulation (15%) would be a gross understatement. Am I wrong for expecting a desk power supply to do better than this? I had purchased this 4245 years ago because the price was right AND that it can run on 117 or 220 volts. At one time I had been contemplating a move to the Philippines and a 220v supply would be needed. By the way, nothing else running here in the shack other than a computer which was in sleep mode anyway, so line voltage sag likely is not the issue. So, if this this a common problem with the MFJ stuff, what other 25+ amp supplies are folks using with their K3’s that have better regulation than 15%? Jim / W6JHB ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Don Wilhelm
Don, Excellent advice! While I have a little bit of voltage drop, will run a parallel set of leads directly to my battery charged by my PowerGate PG40 s directly rather than through the rigrunner. Connection resistance was removed years ago but your suggestion cuts out two connectors. I like that a lot. Why didn't I think of that????
73, Bill K9YEQ ----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Don Wilhelm Sent: Thursday, March 9, 2017 7:24 PM To: James Bennett <[hidden email]>; Elecraft Reflector Reflector <[hidden email]> Subject: Re: [Elecraft] K3 Power Supply Question Jim, Get your DMM out and make the same measurement at the power supply terminals. If you see a substantial voltage sag during transmit there, you can blame the power supply. But if the voltage stays close to constant, the problem is voltage drop in the power cabling. The RigRunner will contribute some drop due to the extra contact points and even #12 or #10 wire has some resistance. If the power supply is good, run a power cable direct from the power supply to the K3 and run another power cable to the rigrunner. Run the accessories in the shack from the rigrunner. 73, Don W3FPR On 3/9/2017 8:09 PM, James Bennett wrote: > Hi All - > > Haven’t had any issues with the above configuration. Until today, when I happened to punch the K3 DISP button, changing it from reading my VFO B frequency to the other various bits of information. One of them was the rig voltage. Sitting there on 17 meters in CW mode receive it was showing a nice 13.8V. Cool. I hit the key and - wait a minute…… it dropped way down to 12.4v. Huh - not so cool. My first thought was that the Boost Regulator was not doing it’s job. But I decided to start trouble shooring at ground zero - the MFJ 4245. I disconnected it from the Power Gate and ran it directly to the K3. Key up = 13.8V. Key down = 12.0V. Yikes! I think (IMHO) calling this poor regulation (15%) would be a gross understatement. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Don Wilhelm
I put my DMM leads on the front terminals of the 4545 and with key down, no change at all: 13.9V, so it appears that MFJ gets a pass on this one.
To do my testing I had run the 4545 directly to the K3 and not through the Rig Runner. However, to do that I had simply hooked the cable from the 4245 that used to go to the Rig Runner into the end of the cable going to the K3, basically taking the Rig Runner, Power Gate, and Boost Regulator out of the picture. This gave me two cables, total of about 10 feet, with three APP connectors. Thus the connection went from the 4245 through a five foot cable and some ferrite donuts into another five foot cable to the back of the K3. The voltage dropped to 12.5 on the K3 meter. With some work, I pulled the cable out of the K3 and connected the 4245 cable with the ferrites directly into the K3. With this combination (only ONE cable and Power Poles at the K3 end) the voltage dropped from 13.9 to 13.1. This means that a second five foot length of cable and two APP’s caused a loss of .6 volts. So, what does all this mean? Since I am not using wimpy, skinny wire I have to conclude that perhaps the APP’s might be the cause of some of this voltage drop. With the original configuration I had using the AGM battery, Power Gate, Boost Regulator, and Rig Runner, there are a bunch of APP’s in the circuit, in addition to several feet of wire. I “could” simply connect the 4245 directly to the K3 and settle for a drop of .8 volts (13.9 to 13.1), but that kinda defeats the purpose of having a solar / battery backup system and a power distribution system. I thought this issue would be solved by replacing the MFJ PS with something else, but it is looking a LOT more complex at this point. Crap - what is one supposed to do? Jim / W6JHB > On Mar 9, 2017, at 5:23 PM, Don Wilhelm <[hidden email]> wrote: > > Jim, > > Get your DMM out and make the same measurement at the power supply terminals. > If you see a substantial voltage sag during transmit there, you can blame the power supply. But if the voltage stays close to constant, the problem is voltage drop in the power cabling. > > The RigRunner will contribute some drop due to the extra contact points and even #12 or #10 wire has some resistance. > > If the power supply is good, run a power cable direct from the power supply to the K3 and run another power cable to the rigrunner. Run the accessories in the shack from the rigrunner. > > 73, > Don W3FPR > > On 3/9/2017 8:09 PM, James Bennett wrote: >> Hi All - >> >> Haven’t had any issues with the above configuration. Until today, when I happened to punch the K3 DISP button, changing it from reading my VFO B frequency to the other various bits of information. One of them was the rig voltage. Sitting there on 17 meters in CW mode receive it was showing a nice 13.8V. Cool. I hit the key and - wait a minute…… it dropped way down to 12.4v. Huh - not so cool. My first thought was that the Boost Regulator was not doing it’s job. But I decided to start trouble shooring at ground zero - the MFJ 4245. I disconnected it from the Power Gate and ran it directly to the K3. Key up = 13.8V. Key down = 12.0V. Yikes! I think (IMHO) calling this poor regulation (15%) would be a gross understatement. >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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I am using an Astron 35 amp ps.
I did not use a dmm, just the meter on the k3. I only got a .2 drop when I connected direct with a five foot thick gauge wire. But using the same pwrgate setup as yours it dropped a full volt or more on transmit. A friend had problems running in a mobile setting with battery backup he went to a voltage boost regulator and it all works. From what I am learning the K3 needs a strong, stable power supply to be reliable. From: Elecraft [mailto:[hidden email]] On Behalf Of James Bennett Sent: Thursday, March 9, 2017 9:01 PM To: Elecraft Reflector Reflector <[hidden email]> Subject: Re: [Elecraft] K3 Power Supply Question I put my DMM leads on the front terminals of the 4545 and with key down, no change at all: 13.9V, so it appears that MFJ gets a pass on this one. To do my testing I had run the 4545 directly to the K3 and not through the Rig Runner. However, to do that I had simply hooked the cable from the 4245 that used to go to the Rig Runner into the end of the cable going to the K3, basically taking the Rig Runner, Power Gate, and Boost Regulator out of the picture. This gave me two cables, total of about 10 feet, with three APP connectors. Thus the connection went from the 4245 through a five foot cable and some ferrite donuts into another five foot cable to the back of the K3. The voltage dropped to 12.5 on the K3 meter. With some work, I pulled the cable out of the K3 and connected the 4245 cable with the ferrites directly into the K3. With this combination (only ONE cable and Power Poles at the K3 end) the voltage dropped from 13.9 to 13.1. This means that a second five foot length of cable and two APP’s caused a loss of .6 volts. So, what does all this mean? Since I am not using wimpy, skinny wire I have to conclude that perhaps the APP’s might be the cause of some of this voltage drop. With the original configuration I had using the AGM battery, Power Gate, Boost Regulator, and Rig Runner, there are a bunch of APP’s in the circuit, in addition to several feet of wire. I “could” simply connect the 4245 directly to the K3 and settle for a drop of .8 volts (13.9 to 13.1), but that kinda defeats the purpose of having a solar / battery backup system and a power distribution system. I thought this issue would be solved by replacing the MFJ PS with something else, but it is looking a LOT more complex at this point. Crap - what is one supposed to do? Jim / W6JHB > On Mar 9, 2017, at 5:23 PM, Don Wilhelm <[hidden email]><mailto:[hidden email]%3e> wrote: > > Jim, > > Get your DMM out and make the same measurement at the power supply terminals. > If you see a substantial voltage sag during transmit there, you can blame the power supply. But if the voltage stays close to constant, the problem is voltage drop in the power cabling. > > The RigRunner will contribute some drop due to the extra contact points and even #12 or #10 wire has some resistance. > > If the power supply is good, run a power cable direct from the power supply to the K3 and run another power cable to the rigrunner. Run the accessories in the shack from the rigrunner. > > 73, > Don W3FPR > > On 3/9/2017 8:09 PM, James Bennett wrote: >> Hi All - >> >> Haven’t had any issues with the above configuration. Until today, when I happened to punch the K3 DISP button, changing it from reading my VFO B frequency to the other various bits of information. One of them was the rig voltage. Sitting there on 17 meters in CW mode receive it was showing a nice 13.8V. Cool. I hit the key and - wait a minute…… it dropped way down to 12.4v. Huh - not so cool. My first thought was that the Boost Regulator was not doing it’s job. But I decided to start trouble shooring at ground zero - the MFJ 4245. I disconnected it from the Power Gate and ran it directly to the K3. Key up = 13.8V. Key down = 12.0V. Yikes! I think (IMHO) calling this poor regulation (15%) would be a gross understatement. >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]<mailto:[hidden email]> ________________________________ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by James Bennett
I connect my voltage boost, like yours a N8XJK, between the
power supply mess and the K3. (I run it in RF Enabled mode.) That results in my K3 getting the voltage it needs, and the voltage loss in all the other connections getting made up. 73 Bill AE6JV On 3/9/17 at 9:00 PM, [hidden email] (James Bennett) wrote: >Crap - what is one supposed to do? ----------------------------------------------------------------------- Bill Frantz |Security, like correctness, is| Periwinkle (408)356-8506 |not an add-on feature. - Attr-| 16345 Englewood Ave www.pwpconsult.com |ibuted to Andrew Tanenbaum | Los Gatos, CA 95032 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by James Bennett
Minimize all cable lengths. No more than necessary.
Verify (actually look at) that SLL APP connectors are FULLY SEATED! Meaning inspect the open end for seeing only one price of metal. Check the Anderson web site for a cut away picture of the cross-section of a properly assembled APP. I use #10 wire for my K3 cables. Use PowerGate to charge battery and run accessories. Run radio from separate cable to PS. When power goes out reconnect radio to battery. Sent from my iPhone ...nr4c. bill > On Mar 10, 2017, at 12:00 AM, James Bennett <[hidden email]> wrote: > > I put my DMM leads on the front terminals of the 4545 and with key down, no change at all: 13.9V, so it appears that MFJ gets a pass on this one. > > To do my testing I had run the 4545 directly to the K3 and not through the Rig Runner. However, to do that I had simply hooked the cable from the 4245 that used to go to the Rig Runner into the end of the cable going to the K3, basically taking the Rig Runner, Power Gate, and Boost Regulator out of the picture. This gave me two cables, total of about 10 feet, with three APP connectors. > > Thus the connection went from the 4245 through a five foot cable and some ferrite donuts into another five foot cable to the back of the K3. The voltage dropped to 12.5 on the K3 meter. With some work, I pulled the cable out of the K3 and connected the 4245 cable with the ferrites directly into the K3. With this combination (only ONE cable and Power Poles at the K3 end) the voltage dropped from 13.9 to 13.1. This means that a second five foot length of cable and two APP’s caused a loss of .6 volts. > > So, what does all this mean? Since I am not using wimpy, skinny wire I have to conclude that perhaps the APP’s might be the cause of some of this voltage drop. With the original configuration I had using the AGM battery, Power Gate, Boost Regulator, and Rig Runner, there are a bunch of APP’s in the circuit, in addition to several feet of wire. I “could” simply connect the 4245 directly to the K3 and settle for a drop of .8 volts (13.9 to 13.1), but that kinda defeats the purpose of having a solar / battery backup system and a power distribution system. I thought this issue would be solved by replacing the MFJ PS with something else, but it is looking a LOT more complex at this point. Crap - what is one supposed to do? > > Jim / W6JHB > > > > > > >> On Mar 9, 2017, at 5:23 PM, Don Wilhelm <[hidden email]> wrote: >> >> Jim, >> >> Get your DMM out and make the same measurement at the power supply terminals. >> If you see a substantial voltage sag during transmit there, you can blame the power supply. But if the voltage stays close to constant, the problem is voltage drop in the power cabling. >> >> The RigRunner will contribute some drop due to the extra contact points and even #12 or #10 wire has some resistance. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by George Thornton
On Thu,3/9/2017 9:29 PM, George Thornton wrote:
> From what I am learning the K3 needs a strong, stable power supply to be reliable. ANY ham rig needs that. :) At 100W, the K3 draws about 20A keydown. Do Ohm's Law on the wiring between the power supply and the K3. The simple answer is short, fat copper, straight from the supply to the radio. AND good quality connectors. Those power distribution strips can easily drop a volt or so. I run #10-2 to my radios. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Nr4c
Folks - thanks for all the input. I think I may have found one of the culprits in the system - oxidation. I put everything back together the way it was to begin with so I could switch back and forth between the K3 and KX3 power displays. I have a KXPA100 behind the KX3 so the load on the MFJ 4245 should be about the same with either one transmitting 100 watts and the other one receiving. What I see now is 13.9 volts on receive and 13.0 - 13.1 during transmit. Waayyyyy better than the drop to 12.0 I saw yesterday!
I might get ambitious and “upgrade” the cables from #12 to #10 and ensure that the APP contacts used are the 30 or 45 amp versions. Will also look into a re-design of the Boost Regulator’s position in the power system. RIght now it supplies boosted power to the Rig Runner. I think it’ll be an easy matter to swap some cabling around and have the output of the Power Gate go to the Rig Runner and have the Boost Regulator tie into the Rig Runner, delivering it’s output directly to the KX3, K3, and KXPA100. I believe this is one of the suggestions made by W3FPR. I’m pretty sure my desk lamp and the PX3 won’t mind only having 12.8 v instead of 13.9! :-) 73, Jim Jim Bennett / W6JHB Folsom, CA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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