Re: [Elecraft] Highest power supply voltage for K2?
Hi Dan, I would be very hesitant to use this technique on expensive equipment. Gradually turning up the voltage while watching the current can lead to a problem that doesn't show up immediately since components can be operated at a higher than normal temperature for a while but their failure rate goes up. After a few hours, days, weeks, your circuit may be damaged. The determination of absolute max input voltage depends on a lot of factors and it's a major engineering problem to determine the safe value. For example, the power rating of the regulators depends on how they are mounted. It may not be convenient to measure their case temperature to characterize a particular application. Alternatively, one can be conservative and use the databook values. Since the guys at Elecraft say 15V, I would go along with that. If the power supply is not well regulated, consider the max value with no load. 73/ Bob - W5BIG - Original Message - From: "Dan Barker" <[EMAIL PROTECTED]> To: "Elecraft" Sent: Tuesday, November 30, 2004 7:29 AM Subject: RE: [Elecraft] Highest power supply voltage for K2? > I've always done the following to see if I was going to toast something. > Maybe someone can tell me the error of may ways (the last thing I did this > on was a $1,400 Video Camera - if the method is dangerous, I'll stop!). > > I hook the 6V Camera up to a 6V power supply (actually a variable voltage > PS) through an ammeter. I slowly advance the voltage (toward the 9.6V target > of the high-capacity batteries stolen from my Electric Zagi model airplane). > > I figure if the current goes up, I'm going to cook something. If the current > decreases, then the power being dissipated is roughly constant so I'm not > cooking anything. > > ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Highest power supply voltage for K2?
I worked in the semiconductor industry and I remember frying a bunch of chips when I reached a knee in the current draw. You can increase the voltage until something breaks down, and then you're hosed. Lots of current flows and your semiconducting device is no longer conducting at all since you let all the magic smoke out. I'd suggest the correct batteries, but I worked in a ham radio repair shop years ago and I know how *(@#*&$ cheap hams are so I know telling you to pay any extra to use the correct batteries will fall on deaf ears. :) - Original Message - From: "Dan Barker" <[EMAIL PROTECTED]> I hook the 6V Camera up to a 6V power supply (actually a variable voltage PS) through an ammeter. I slowly advance the voltage (toward the 9.6V target of the high-capacity batteries stolen from my Electric Zagi model airplane). I figure if the current goes up, I'm going to cook something. If the current decreases, then the power being dissipated is roughly constant so I'm not cooking anything. If I'm WAY off in left field, let me know. I'll spring for the $60 camera batteries that don't last worth a poop instead of the [already on hand] airplane batteries that hold up nicely. -- Hisashi T Fujinaka - [EMAIL PROTECTED] BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte ___ 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] Highest power supply voltage for K2?
If the airplane batteries are clearly superior in performance, you should consider making a pack of them that meet the voltage requirements of your camera. In almost every circumstance, the excess voltage is being dissipated as heat and/or causing more direct damage. On Tue, 30 Nov 2004, W3FPR - Don Wilhelm wrote: Dan, You method will work in some cases, but can result in component damage in others - there is no one answer, it depends on the device and its design. I personally wouldn't try that with my digital camera (it is not a throw-away expense to replace it). Far better to use a regulator or even a string of diodes to bring the voltage to something less than the max specified for the device in question. 73, Don W3FPR - Original Message - From: "Dan Barker" <[EMAIL PROTECTED]> To: "Elecraft" Sent: Tuesday, November 30, 2004 8:29 AM Subject: RE: [Elecraft] Highest power supply voltage for K2? I've always done the following to see if I was going to toast something. Maybe someone can tell me the error of may ways (the last thing I did this on was a $1,400 Video Camera - if the method is dangerous, I'll stop!). I hook the 6V Camera up to a 6V power supply (actually a variable voltage PS) through an ammeter. I slowly advance the voltage (toward the 9.6V target of the high-capacity batteries stolen from my Electric Zagi model airplane). I figure if the current goes up, I'm going to cook something. If the current decreases, then the power being dissipated is roughly constant so I'm not cooking anything. If I'm WAY off in left field, let me know. I'll spring for the $60 camera batteries that don't last worth a poop instead of the [already on hand] airplane batteries that hold up nicely. If I'm NOT off in left field, this is a nice way to check out a circuit without a diagram or any disassembly/tracing. Dan / WG4S / K2 #2456 I a message dated 30/11/04 02:01:23 GMT Standard Time, [EMAIL PROTECTED] writes: What is the absolute highest safe voltage you can pump into the K2 before you start overheating the regulators etc? ___ 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/elecraftHelp: 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] Highest power supply voltage for K2?
Dan, You method will work in some cases, but can result in component damage in others - there is no one answer, it depends on the device and its design. I personally wouldn't try that with my digital camera (it is not a throw-away expense to replace it). Far better to use a regulator or even a string of diodes to bring the voltage to something less than the max specified for the device in question. 73, Don W3FPR - Original Message - From: "Dan Barker" <[EMAIL PROTECTED]> To: "Elecraft" Sent: Tuesday, November 30, 2004 8:29 AM Subject: RE: [Elecraft] Highest power supply voltage for K2? I've always done the following to see if I was going to toast something. Maybe someone can tell me the error of may ways (the last thing I did this on was a $1,400 Video Camera - if the method is dangerous, I'll stop!). I hook the 6V Camera up to a 6V power supply (actually a variable voltage PS) through an ammeter. I slowly advance the voltage (toward the 9.6V target of the high-capacity batteries stolen from my Electric Zagi model airplane). I figure if the current goes up, I'm going to cook something. If the current decreases, then the power being dissipated is roughly constant so I'm not cooking anything. If I'm WAY off in left field, let me know. I'll spring for the $60 camera batteries that don't last worth a poop instead of the [already on hand] airplane batteries that hold up nicely. If I'm NOT off in left field, this is a nice way to check out a circuit without a diagram or any disassembly/tracing. Dan / WG4S / K2 #2456 I a message dated 30/11/04 02:01:23 GMT Standard Time, [EMAIL PROTECTED] writes: What is the absolute highest safe voltage you can pump into the K2 before you start overheating the regulators etc? ___ 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] Highest power supply voltage for K2?
Guys, there are several things to consider when raising the input voltage to the K2 family. First, power loss in the regulators. There are several 5V, 6V and 8V regulators on board. If you have a 12V source to a 6V regulator, you will be burning up as much power in heating up the regulator as in powering the circuit. At 15 volts you will be wasting twice as much power in the 5V regulator as the circuitry it feeds. I'm sure you would much rather have that power go out the antenna port or the speaker than to warm the case. The other big thing to consider is the voltage rating of the components. Some of the electrolytics in the K2 or its various accessories are rated in the 15 to 20 volt range in order to keep the size down. Do you _really_ want to risk popping these things? The max rated input voltage to the K2 and its accessories is 15 volts for a very good reason. Your K2 will last much longer if you keep the power supply below this level... On Nov 29, 2004, at 11:53 PM, Tom Althoff wrote: The wall wart is rated at 15VDC but as Don pointed out the regulation on these things is pretty poor and under no load I was experiencing 17VDC. Under a 1 amp load the voltage was 15.1. Since most of the time I'm not transmitting under load I was hesitant to apply it until I checked here. The manual that came with my K2 when discussing the output capacity of the PA stages states on page 102 of the Theory of Operation... "The transmit strip is conservatively rated to provide excellent reliability and immunity to high SWR. The same push-pull final could be pushed to over 40W on the lower bands." This is what let me to believe there might be some leeway. I doubt they were talking about trying to draw 4 times as much current to get the 40W but to run it at a higher voltage than was in the specs. - Jack Brindle, W6FB - ___ 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] Highest power supply voltage for K2?
I've always done the following to see if I was going to toast something. Maybe someone can tell me the error of may ways (the last thing I did this on was a $1,400 Video Camera - if the method is dangerous, I'll stop!). I hook the 6V Camera up to a 6V power supply (actually a variable voltage PS) through an ammeter. I slowly advance the voltage (toward the 9.6V target of the high-capacity batteries stolen from my Electric Zagi model airplane). I figure if the current goes up, I'm going to cook something. If the current decreases, then the power being dissipated is roughly constant so I'm not cooking anything. If I'm WAY off in left field, let me know. I'll spring for the $60 camera batteries that don't last worth a poop instead of the [already on hand] airplane batteries that hold up nicely. If I'm NOT off in left field, this is a nice way to check out a circuit without a diagram or any disassembly/tracing. Dan / WG4S / K2 #2456 I a message dated 30/11/04 02:01:23 GMT Standard Time, [EMAIL PROTECTED] writes: What is the absolute highest safe voltage you can pump into the K2 before you start overheating the regulators etc? ___ 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] Highest power supply voltage for K2?
Bob G3VVT wrote "...a string of 1N4000 series 1A diodes could bring down the voltage to what you require..." I'm glad you mentioned it Bob. It's my favorite way to drop a DC supply a few volts down. I have four 10amp rectifiers here which would give me 2.4V drop..17.2 - 2.4 = 14.8. The wall wart is rated at 15VDC but as Don pointed out the regulation on these things is pretty poor and under no load I was experiencing 17VDC. Under a 1 amp load the voltage was 15.1. Since most of the time I'm not transmitting under load I was hesitant to apply it until I checked here. The manual that came with my K2 when discussing the output capacity of the PA stages states on page 102 of the Theory of Operation... "The transmit strip is conservatively rated to provide excellent reliability and immunity to high SWR. The same push-pull final could be pushed to over 40W on the lower bands." This is what let me to believe there might be some leeway. I doubt they were talking about trying to draw 4 times as much current to get the 40W but to run it at a higher voltage than was in the specs. I just need something to keep the battery charged while I'm at the cabin. I didn't want to bring my 10AMP boat anchor supply so the wall wart was a small, though less than optimum, solution. I'll eventually add Don's smart charger hookup to help extend the life of the battery. Thanks to all who answered. 73 de Tom K2TA - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; elecraft@mailman.qth.net Sent: Monday, November 29, 2004 9:29 PM Subject: Re: [Elecraft] Highest power supply voltage for K2? In a message dated 30/11/04 02:01:23 GMT Standard Time, [EMAIL PROTECTED] writes: What is the absolute highest safe voltage you can pump into the K2 before you start overheating the regulators etc? Most manufacturers seem to give 16V as the upper sustained voltage limit for DC input on 12V equipment. The 2SC1969 PA transistors are rated at this in their data sheets and the regulators seem to come out at 25V as their maximum input so should not represent a problem. Faced with the situation you have with 1.2V above the 16V normal limit a string of 1N4000 series 1A diodes could bring down the voltage to what you require. Normal forward voltage drop comes out somewhere near 0.6V per diode, so two in series would probably fit the bill. Used this technique to power a Sony 2001 SW broadcast radio I had in the Middle East for over 20 years needing 4.5VDC power source. Bob, G3VVT ___ 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] Highest power supply voltage for K2?
[EMAIL PROTECTED] writes: What is the absolute highest safe voltage you can pump into the K2 before you start overheating the regulators etc? - The K2 manual says "9 to 15 vdc" I'd be inclined to believe them if you want to keep the smoke inside those components... Ron AC7AC ___ 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] Highest power supply voltage for K2?
In a message dated 30/11/04 02:01:23 GMT Standard Time, [EMAIL PROTECTED] writes: What is the absolute highest safe voltage you can pump into the K2 before you start overheating the regulators etc? Most manufacturers seem to give 16V as the upper sustained voltage limit for DC input on 12V equipment. The 2SC1969 PA transistors are rated at this in their data sheets and the regulators seem to come out at 25V as their maximum input so should not represent a problem. Faced with the situation you have with 1.2V above the 16V normal limit a string of 1N4000 series 1A diodes could bring down the voltage to what you require. Normal forward voltage drop comes out somewhere near 0.6V per diode, so two in series would probably fit the bill. Used this technique to power a Sony 2001 SW broadcast radio I had in the Middle East for over 20 years needing 4.5VDC power source. Bob, G3VVT ___ 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
