Re: [Elecraft] Use of PC power supplies with K2
Ken : I am still in the process of building my K2 but I have used the CUP36 13.5V / 2.4 A Switching supply sold by Morse Express on both my K1 and KX1 and it works very well with no generated noise. Very convenient when operating from hotel rooms etc. http://www.mtechnologies.com/cup/ Michael VE3WMB / VA2NB __ 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
[Elecraft] Use of PC power supplies with K2
I would like to hear from anyone who has attempted to use one of the small external PC AC adapter power supplies with a K2. They are, of course, switchers, so I am not very hopeful. I have found a couple of possible candidates, one a Meanwell P40A-4PSJ rated at 13.8 volts at 2.66 amps and the other an APS AD-740U-1138, rated at 13.8 volts at 2.8 amps. They seem to have somewhat comparable specs as to regulation, ripple, and protection. I suspect they would be pretty bad on RFI, so even though they can be had cheaply, they may not be worth the grief. My fallback position would likely be the little unit from Gamma Research, HPS-1a, but that will be twice as heavy and probably ten times more expensivebut from what I've read about it, it is not very noisy electrically. I would really appreciate any thoughts, especially those with first hand experience. This would only be for portable operation, not normal use. Thanks. 73, Ken Moorman, NU4I __ 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
Re: [Elecraft] Use of PC power supplies with K2
Ken... The general subject of RFI/switching power supplies has been bruited about on this list server several times. I personally have had excellent experience with the several that I use. These include a 20 amp, 13.8 V supply from pyramid and two 25 amp, 13.8 volt supplies from Radio Shack. These supplies sit within inches of my K3/100 and my ICOM 910H and cause no interference that I can detect. On the other hand, I have a circline fluorescent lamp with a magnifier that I transplanted from my workbench to my operating site, about which I made the following discovery. The lamp itself runs off a power supply at the base of the tensor arms. Turning the lamp on and off produces no change in interference, but unplugging the lamp from the wall outlet reduces hash noise on 20 meters by about 3 S units !!!. The wall-wart-like power supply in the base of this lamp is very noisy, and the lamp has accordingly been banished to a less sensitive site. My summary comment would be that power supplies run the gamut wrt RFI problems, and that one might well have to proceed by trial-and-error. I have always rejected use of the PC-type power supply because they usually come with a spaghetti of different wires intended for different functions within the computer. The small Radio Shack 25 amp supplies are about the same volume as a typical PC supply, and a great deal more congenial (cosmetically) than the latter. John Ragle -- W1ZI = On 10/3/2010 1:47 PM, Kenneth Moorman wrote: I would like to hear from anyone who has attempted to use one of the small external PC AC adapter power supplies with a K2. They are, of course, switchers, so I am not very hopeful. __ 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
[Elecraft] Use of PC power supplies with K2
Thanks John, I should have stated that this would be the K2/10. These little switchers are the sort that powered laptops. They are sealed units with single output voltages, not the boxes that go into the desktop machines with multiple output voltages. I should have been clearer about this. Ken, NU4I My summary comment would be that power supplies run the gamut wrt RFI problems, and that one might well have to proceed by trial-and-error. I have always rejected use of the PC-type power supply because they usually come with a spaghetti of different wires intended for different functions within the computer. The small Radio Shack 25 amp supplies are about the same volume as a typical PC supply, and a great deal more congenial (cosmetically) than the latter. John Ragle -- W1ZI __ 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
Re: [Elecraft] Use of PC power supplies with K2
I have used the MFJ-4103 (13.8 v, 2.89 amps) with my K2 and haven't noticed any switching noise issues. Bob, N7XY On Oct 3, 2010, at 10:47 AM, Kenneth Moorman wrote: I would like to hear from anyone who has attempted to use one of the small external PC AC adapter power supplies with a K2. They are, of course, switchers, so I am not very hopeful. I have found a couple of possible candidates, one a Meanwell P40A-4PSJ rated at 13.8 volts at 2.66 amps and the other an APS AD-740U-1138, rated at 13.8 volts at 2.8 amps. They seem to have somewhat comparable specs as to regulation, ripple, and protection. I suspect they would be pretty bad on RFI, so even though they can be had cheaply, they may not be worth the grief. My fallback position would likely be the little unit from Gamma Research, HPS-1a, but that will be twice as heavy and probably ten times more expensivebut from what I've read about it, it is not very noisy electrically. I would really appreciate any thoughts, especially those with first hand experience. This would only be for portable operation, not normal use. Thanks. __ 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
[Elecraft] Use of PC power supplies with K2
I have used the MFJ-4103 on my K1, K2, and mni other qrp rigs with no problems. George/W2BPI __ 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
