Hi Rich: A couple of more things. First do the math. Assuming 20 amps of transmit current (that's my rig @100 watts output) with a 2 volt drop is 40 watts of lost energy (not my rig). That also happens to be the power rating of my soldering iron. To point, something is likely to be getting warm. You should be able to find your problem by touching your cables and connectors while transmitting a 100 watts of RTTY, AM, etc. Also, I hope you are not using a diode type power sharing device sold to share power supply and battery. Think about it. Why do they need a big heat sink? Big heat sinks mean lots of wasted power. 73 Fred, AE6QL
-----Original Message----- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Rich Sent: Monday, October 26, 2015 10:05 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Voltage on TX Thanks to all. I have check my PS and it does not fluctuate even a tenth of a volt on TX. With the radio connected directly to the PS. I am now seeing 14.1 VDC and 12.0 VDC on TX. So I need to look closer at the wire gauge and connectors. That is still about 2VDC drop. Thanks for the help rich On 10/26/2015 12:09 PM, Phil Wheeler wrote: > If the wire gauge is OK and the supply regulation is not at fault, > give some attention to the connectors at each end of the cable, too. A > drop of 2.8 Volts points to some sort of issue. > > 73, Phil W7OX > > On 10/26/15 9:02 AM, Jim Brown wrote: >> On Mon,10/26/2015 8:48 AM, Rich wrote: >>> My K3 shows 13.7VDC on RX. When I TX that reading drops to 10.9VDC. >>> Is that a normal drop? >> >> It's not good. Two possible reasons -- poor regulation of the power >> supply and IR drop in the power cable. >> >> How long is the power cable between the K3 and power supply? What >> wire gauge? Do the arithmetic for Ohm's law for the IR drop in that >> length of that wire gauge. and remember to use the length of the >> cable x2 (for two conductors). Resistance per ft for various wire >> gauges is in the ARRL Handbook. >> >> Put a voltmeter across the output terminals of the power supply and >> check the voltage. It's also possible that the power supply has poor >> regulation. >> >> 73, Jim K9YC > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message delivered to > rwnewbo...@comcast.net > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to fptowns...@earthlink.net ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
