Gary You could wire the power cable direct to the pcb inside the K3, that would further reduce your losses and avoid connector damage/intermittence if it's being wiggled a lot.
David G3UNA ----- Original Message ----- From: "Gary Smith" <g...@doctorgary.net> To: <Elecraft@mailman.qth.net> Sent: Tuesday, January 27, 2009 4:14 PM Subject: Re: [Elecraft] K3/100 and the PSU >I used the included power cable and did notice a drop in the voltage > of about a volt. I had bought a "35" amp, 25 amp continuous Astron > power supply which has variable voltage but does not include a remote > probe as the one I made from the ARRL handbook offered. The probe was > used to ID voltage drop and the PS responded by upping the voltage as > needed so 13.8 would be at the rig at all times. > > Using that probe with my old TR7 kept the voltage dead on at the rig. > I was saddened to have left that in Indiana as a gift to a friend for > the PS components were made from an old Wang computer I canabalized > in the 80's and I designed it for an easy 80 amps and it weighed over > 100 pounds and was on casters. It was too much to move and is in use > today by my friend but I digress; > > I felt the best option with the K3 and the Astron VS35M was to use a > different power cable so I cut the cable aproximately 5" from the > Power Pole and soldered that short end to an 8 gauge cable made of > very fine wire which I bought from Home Depot. This was part of heavy > cable at about $5/foot with four conductors and a heavy neoprene > outer jacket. > > I stripped the jacket, used two of the connectors and attached a 4' > length to the Astron & k3. > >>From the K3 internal volt meter it reads: > > 14.0V at idle: > > At 25W the drop is .2 = 13.8 > At 50W the drop is .3 = 13.7 > At 75W the drop is .3 = 13.7 > At 100W the drop is .4 = 13.6 > at 120W the drop is .4 = 13.6 > > Not as regulated at the rig as my old homebrew PS but certainly a > very little voltage drop. When running the amp I never use more than > 50W drive so I'm content. > > One caveat is I felt the need to devise a mount to keep the power > cord from moving around behind the radio. I know the PowerPoles are > loved by many but I see these smaller variety as a weak point and > don't much like them attached to the rig. The old TenTec attachments > were not as sexy as these PowerPoles but I felt they had more heft > and I didn't feel concern that someday the internal soldering would > come loose from repeated motion as the rig is located from one site > to another. > > Perhaps if the next larger size of PowerPole were utilized I would > feel it more sturdy? > > 73, > GAry > KA1J > _______________________________________________ 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
