At first i suspected my Solar power system which was installed a year ago,
but now I plugged my K3 S/N 7317 directly into my 25A switching DC power supply, and when key down, 100W in CW, on the internal K3 Power Meter i see a voltage drop from 13.6 to 12.0VDC. My power cord is a 6', 10ga stranded copper wire pair with Andersen Power Pole connectors. I have tried three separate power cords, all 10ga with power pole connectors, but with no change in the voltage drop scenario. If anyone has suggestions of where the problem lies, I am all ears. Obviously, when operating SSB the drop is present but not as severe. What am i dealing with? Better yet, how do i fix it? Thanks in advance. Cheers, Mike, K5MP -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ 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 |
Hi Mike, What are your voltage readings at the power supply end of your six foot power cords? None of my K3s do behave the way you describe. 73 Frank W3LPL ----- Original Message ----- From: "mjpilgrim" <[hidden email]> To: [hidden email] Sent: Monday, February 25, 2019 6:55:01 PM Subject: [Elecraft] K3/100 Voltage Drop when transmitting At first i suspected my Solar power system which was installed a year ago, but now I plugged my K3 S/N 7317 directly into my 25A switching DC power supply, and when key down, 100W in CW, on the internal K3 Power Meter i see a voltage drop from 13.6 to 12.0VDC. My power cord is a 6', 10ga stranded copper wire pair with Andersen Power Pole connectors. I have tried three separate power cords, all 10ga with power pole connectors, but with no change in the voltage drop scenario. If anyone has suggestions of where the problem lies, I am all ears. Obviously, when operating SSB the drop is present but not as severe. What am i dealing with? Better yet, how do i fix it? Thanks in advance. Cheers, Mike, K5MP -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ 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 ______________________________________________________________ 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 |
I have a K3 that behaves similarly to what Mike described. I switched from an Astron 25 amp (15 years or more old) power supply to a switching power supply. Problem solved. One would think the problem was my Astron power supply, but I don’t see any such power drop when I use my Astron with other 100 watt rigs. Very strange.
Jimmy Walker, WA4ILO Macon, GA > On Feb 25, 2019, at 1:58 PM, [hidden email] wrote: > > > Hi Mike, > > What are your voltage readings at the power supply end of your > six foot power cords? > > > None of my K3s do behave the way you describe. > > > 73 > Frank > W3LPL > > > ----- Original Message ----- > > From: "mjpilgrim" <[hidden email]> > To: [hidden email] > Sent: Monday, February 25, 2019 6:55:01 PM > Subject: [Elecraft] K3/100 Voltage Drop when transmitting > > At first i suspected my Solar power system which was installed a year ago, > but now I plugged my K3 S/N 7317 directly into my 25A switching DC power > supply, and when key down, 100W in CW, on the internal K3 Power Meter i see > a voltage drop from 13.6 to 12.0VDC. My power cord is a 6', 10ga stranded > copper wire pair with Andersen Power Pole connectors. I have tried three > separate power cords, all 10ga with power pole connectors, but with no > change in the voltage drop scenario. If anyone has suggestions of where the > problem lies, I am all ears. Obviously, when operating SSB the drop is > present but not as severe. What am i dealing with? Better yet, how do i > fix it? Thanks in advance. > Cheers, > Mike, K5MP > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > ______________________________________________________________ > 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 > > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
In reply to this post by mjpilgrim
I had a similar problem. I checked the key-down voltage at my power supply, and was surprised to see that it was low (I don't recall the exact voltage).I'm using an Astron linear power supply. I replaced the voltage regulator in the power supply, and the problem was solved.73,Don Sayler W7OXRSent via my Mobile
-------- Original message --------From: mjpilgrim <[hidden email]> Date: 2/25/19 10:55 AM (GMT-08:00) To: [hidden email] Subject: [Elecraft] K3/100 Voltage Drop when transmitting At first i suspected my Solar power system which was installed a year ago,but now I plugged my K3 S/N 7317 directly into my 25A switching DC powersupply, and when key down, 100W in CW, on the internal K3 Power Meter i seea voltage drop from 13.6 to 12.0VDC. My power cord is a 6', 10ga strandedcopper wire pair with Andersen Power Pole connectors. I have tried threeseparate power cords, all 10ga with power pole connectors, but with nochange in the voltage drop scenario. If anyone has suggestions of where theproblem lies, I am all ears. Obviously, when operating SSB the drop ispresent but not as severe. What am i dealing with? Better yet, how do ifix it? Thanks in advance.Cheers,Mike, K5MP--Sent from: http://elecraft.365791.n2.nabble.com/______________________________________________________________Elecraft mailing listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:[hidden email] list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
In reply to this post by James Walker
Jimmy,
Astron power supplies have a nasty habit of having loose wiring terminals. They use only pressure to hold the ring terminals on the inside to the terminal bolts. If you can detect even a slight rotation of the bolt when tightening terminals on the outside, remove the covers and tighten those bolts from the inside. The other problem is improperly assembled APP connectors. If you look straight into the end of the connector, if you can see the tip of 2 blades in either side, give the contact blade an extra push from the wire side until the contact blade locks over the locking tab. That is also a cause of APP connectors which tend to pull out with very little tension. 73, Don W3FPR On 2/25/2019 2:12 PM, James Walker wrote: > I have a K3 that behaves similarly to what Mike described. I switched from an Astron 25 amp (15 years or more old) power supply to a switching power supply. Problem solved. One would think the problem was my Astron power supply, but I don’t see any such power drop when I use my Astron with other 100 watt rigs. Very strange. > > Jimmy Walker, WA4ILO > Macon, GA ______________________________________________________________ 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 |
Thanks Don. I’m sure the problem is with with the Astron as you suggest. I’ll try your suggestions when I’m back at home in “shop mode,”
Jimmy > On Feb 25, 2019, at 2:30 PM, Don Wilhelm <[hidden email]> wrote: > > Jimmy, > > Astron power supplies have a nasty habit of having loose wiring terminals. They use only pressure to hold the ring terminals on the inside to the terminal bolts. > If you can detect even a slight rotation of the bolt when tightening terminals on the outside, remove the covers and tighten those bolts from the inside. > > The other problem is improperly assembled APP connectors. If you look straight into the end of the connector, if you can see the tip of 2 blades in either side, give the contact blade an extra push from the wire side until the contact blade locks over the locking tab. > That is also a cause of APP connectors which tend to pull out with very little tension. > > 73, > Don W3FPR > > On 2/25/2019 2:12 PM, James Walker wrote: >> I have a K3 that behaves similarly to what Mike described. I switched from an Astron 25 amp (15 years or more old) power supply to a switching power supply. Problem solved. One would think the problem was my Astron power supply, but I don’t see any such power drop when I use my Astron with other 100 watt rigs. Very strange. >> Jimmy Walker, WA4ILO >> Macon, GA ______________________________________________________________ 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 |
Poor regulation is a common failure mode with Astron linear power
supplies. The problem is equally likely to be either in the power supply section or in the regulator section. There's an excellent troubleshooting and repair procedure here: http://www.repeater-builder.com/astron/astron-repair/astron-repair.html 73 Frank W3LPL ----- Original Message ----- From: "James Walker" <[hidden email]> To: [hidden email] Cc: [hidden email], [hidden email] Sent: Monday, February 25, 2019 7:35:49 PM Subject: Re: [Elecraft] K3/100 Voltage Drop when transmitting Thanks Don. I’m sure the problem is with with the Astron as you suggest. I’ll try your suggestions when I’m back at home in “shop mode,” Jimmy > On Feb 25, 2019, at 2:30 PM, Don Wilhelm <[hidden email]> wrote: > > Jimmy, > > Astron power supplies have a nasty habit of having loose wiring terminals. They use only pressure to hold the ring terminals on the inside to the terminal bolts. > If you can detect even a slight rotation of the bolt when tightening terminals on the outside, remove the covers and tighten those bolts from the inside. > > The other problem is improperly assembled APP connectors. If you look straight into the end of the connector, if you can see the tip of 2 blades in either side, give the contact blade an extra push from the wire side until the contact blade locks over the locking tab. > That is also a cause of APP connectors which tend to pull out with very little tension. > > 73, > Don W3FPR > > On 2/25/2019 2:12 PM, James Walker wrote: >> I have a K3 that behaves similarly to what Mike described. I switched from an Astron 25 amp (15 years or more old) power supply to a switching power supply. Problem solved. One would think the problem was my Astron power supply, but I don’t see any such power drop when I use my Astron with other 100 watt rigs. Very strange. >> Jimmy Walker, WA4ILO >> Macon, GA ______________________________________________________________ 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 |
In reply to this post by mjpilgrim
Well, i have received many helpful replies both publicly here and in private
emails. Thanks to all for those ideas brought forward. What I've gleaned to be most useful from your responses has been the suggestions to investigate the power cord with power poles connecting the K3 to my switching power supply. Per those inputs I've fabricated a shorter (5') cable and insured that I used the crimp terminals rated at 30 AMPS. The initial result has been a reduction of about 30% of my measured voltage drop (now 13.6 Volts in standby to 12.5V when key down 100W CW........ previously the drop was to 12.0)............... Some background info. is that the original observation of a voltage drop occurred as the K3 was connected to my minimal-sized Solar Power supply. After extensive investigation, additional hardening in the wiring, and replacement of a suspect imported power distribution strip, I was convinced there was no voltage drop evidenced there. The battery voltage measured at the input to the referenced DC power distribution strip did not waver under key down tests with the attached K3............. There remained however, the above-mentioned voltage drop displayed in the K3 metering. i plan to rebuild the afore-mentioned 5' power cable, this time soldering the power pole lugs rather than trusting crimped connections. My suspicion that the power cable is suspect, so i plan to address those curiosities before moving on to other possible cause. Thanks again for your continued ideas and suggestions. Regards, Mike, K5MP -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ 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 |
Be sure to use a DVM external to the K3 to measure the voltage at the K3. The input protection diode in the K3 will cause some drop (1/4 to 1/2 volt perhaps). What this means is that the K3 meter will always show less voltage than is really present at the transceiver supply input.
73! Jack, W6FB > On Feb 26, 2019, at 9:37 AM, mjpilgrim <[hidden email]> wrote: > > Well, i have received many helpful replies both publicly here and in private > emails. Thanks to all for those ideas brought forward. > > What I've gleaned to be most useful from your responses has been the > suggestions to investigate the power cord with power poles connecting the K3 > to my switching power supply. Per those inputs I've fabricated a shorter > (5') cable and insured that I used the crimp terminals rated at 30 AMPS. > The initial result has been a reduction of about 30% of my measured voltage > drop (now 13.6 Volts in standby to 12.5V when key down 100W CW........ > previously the drop was to 12.0)............... Some background info. is > that the original observation of a voltage drop occurred as the K3 was > connected to my minimal-sized Solar Power supply. After extensive > investigation, additional hardening in the wiring, and replacement of a > suspect imported power distribution strip, I was convinced there was no > voltage drop evidenced there. The battery voltage measured at the input to > the referenced DC power distribution strip did not waver under key down > tests with the attached K3............. There remained however, the > above-mentioned voltage drop displayed in the K3 metering. > > i plan to rebuild the afore-mentioned 5' power cable, this time soldering > the power pole lugs rather than trusting crimped connections. My suspicion > that the power cable is suspect, so i plan to address those curiosities > before moving on to other possible cause. > > Thanks again for your continued ideas and suggestions. > Regards, > Mike, K5MP > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
Diode voltage drop is approximately 0.7v per diode
Sent from my iPhone > On Feb 26, 2019, at 2:16 PM, Jack Brindle via Elecraft <[hidden email]> wrote: > > Be sure to use a DVM external to the K3 to measure the voltage at the K3. The input protection diode in the K3 will cause some drop (1/4 to 1/2 volt perhaps). What this means is that the K3 meter will always show less voltage than is really present at the transceiver supply input. > > > 73! > Jack, W6FB > >> On Feb 26, 2019, at 9:37 AM, mjpilgrim <[hidden email]> wrote: >> >> Well, i have received many helpful replies both publicly here and in private >> emails. Thanks to all for those ideas brought forward. >> >> What I've gleaned to be most useful from your responses has been the >> suggestions to investigate the power cord with power poles connecting the K3 >> to my switching power supply. Per those inputs I've fabricated a shorter >> (5') cable and insured that I used the crimp terminals rated at 30 AMPS. >> The initial result has been a reduction of about 30% of my measured voltage >> drop (now 13.6 Volts in standby to 12.5V when key down 100W CW........ >> previously the drop was to 12.0)............... Some background info. is >> that the original observation of a voltage drop occurred as the K3 was >> connected to my minimal-sized Solar Power supply. After extensive >> investigation, additional hardening in the wiring, and replacement of a >> suspect imported power distribution strip, I was convinced there was no >> voltage drop evidenced there. The battery voltage measured at the input to >> the referenced DC power distribution strip did not waver under key down >> tests with the attached K3............. There remained however, the >> above-mentioned voltage drop displayed in the K3 metering. >> >> i plan to rebuild the afore-mentioned 5' power cable, this time soldering >> the power pole lugs rather than trusting crimped connections. My suspicion >> that the power cable is suspect, so i plan to address those curiosities >> before moving on to other possible cause. >> >> Thanks again for your continued ideas and suggestions. >> Regards, >> Mike, K5MP >> >> >> >> -- >> Sent from: http://elecraft.365791.n2.nabble.com/ >> ______________________________________________________________ >> 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 > > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
In reply to this post by mjpilgrim
On 2/26/2019 9:37 AM, mjpilgrim wrote:
> What I've gleaned to be most useful from your responses has been the > suggestions to investigate the power cord with power poles connecting the K3 > to my switching power supply. Per those inputs I've fabricated a shorter > (5') cable and insured that I used the crimp terminals rated at 30 AMPS. Ohm's Law still works! 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 |
yep, OHM's law lives, even after at least 61 years since i first studied it
in preparation for my novice test. Furthermore, I'm grateful for the outpouring of ideas and suggestions received here on this forum. I think I have learned enough to convince myself that I have improved my situation as much as i can, and with what remains, I can live with the resultant which appears to be due to the presence of the referenced internal diode which some have suggested would impose a .7V voltage drop. From received suggestions I replaced the input power cable with a 8AWG 6' stranded copper pair with all the power pole connectors firmly crimped to the wires. When plugged into the MFJ switched power supply i measure 13.6V at the power poles on the power supply, and the same 13.6 is measured at the power input on the back of the K3. Under key down 100W CW test, the power supply voltage does not vary at all, either at the power supply or on rear of the K3, and on the internal power meter in the K3 I see a .8V drop to 12.8V......... that's near enough to .7V to declare victory as far as I can see. Having achieved what seems to be normal operations as based on those voltage measurements, I then disabled the MFJ power supply and moved the input power cable on the K3 over to the DC distribution panel from the Solar System batteries. Much to my surprise and pleasure the voltage measurements compared equally to what I registered in the hookup to the MFJ power source. So, now that you have helped put this power concern to rest for me, I will close out this concern as I turn my full attention to fine-tuning my solar power system capabilities, such as incorporating a boost inverter for raising and holding the input voltage at a level more friendly to the K3 operating efficiency. Thanks again for all your suggestions and ideas. Regards, Mike, K5MP -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ 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 |
Now crank up the voltage output on the power supply to 14.1 Volts. This will result in a cleaner signal and lower the amp draw, thus reducing the cable voltage drop slightly (that Ohms Law thingy again).
Enjoy your rig. ps: I’ve replaced the circuit board in several Astron power supplies recently and they were all set to 14.1 Volts right from the factory. Sent from my iPhone ...nr4c. bill > On Feb 26, 2019, at 9:55 PM, mjpilgrim <[hidden email]> wrote: > > yep, OHM's law lives, even after at least 61 years since i first studied it > in preparation for my novice test. > > Furthermore, I'm grateful for the outpouring of ideas and suggestions > received here on this forum. I think I have learned enough to convince > myself that I have improved my situation as much as i can, and with what > remains, I can live with the resultant which appears to be due to the > presence of the referenced internal diode which some have suggested would > impose a .7V voltage drop. > > From received suggestions I replaced the input power cable with a 8AWG 6' > stranded copper pair with all the power pole connectors firmly crimped to > the wires. When plugged into the MFJ switched power supply i measure 13.6V > at the power poles on the power supply, and the same 13.6 is measured at the > power input on the back of the K3. Under key down 100W CW test, the power > supply voltage does not vary at all, either at the power supply or on rear > of the K3, and on the internal power meter in the K3 I see a .8V drop to > 12.8V......... that's near enough to .7V to declare victory as far as I can > see. > > Having achieved what seems to be normal operations as based on those voltage > measurements, I then disabled the MFJ power supply and moved the input power > cable on the K3 over to the DC distribution panel from the Solar System > batteries. Much to my surprise and pleasure the voltage measurements > compared equally to what I registered in the hookup to the MFJ power source. > > So, now that you have helped put this power concern to rest for me, I will > close out this concern as I turn my full attention to fine-tuning my solar > power system capabilities, such as incorporating a boost inverter for > raising and holding the input voltage at a level more friendly to the K3 > operating efficiency. > > Thanks again for all your suggestions and ideas. > Regards, > Mike, K5MP > > > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
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