On Tue, May 17, 2011 at 6:03 AM, Graham Haddock <[email protected]>wrote:
> Hi Brian: > > Well, as you say, the switchers should be much better regulated. Beware > the RF switching > noise/harmonics. Oh, yes, definitely! Most are noisier'n heck. I don't know how they get them into the US as most have little or no filtering. The one I am planning to try at least came with ferrites on the output cable so someone is thinking about the problem. I have several 12V-to-19V switchers that I use to run various laptops. I given up trying to find one that is quiet so I am going to put them in metal boxes with EMI filtering on both input and output. I am going to need them for Field Day. > I have had to replace several switcher wall warts in my shack > with linear regulated warts to quiet down the RF environment. I got tired > of the > "noise humps" chasing me across 30 and 40 Meters. > I hate those. I have eliminated the offenders in the shack but the problem persists. I keep looking for the offenders in my house but haven't found them yet. I may have to resort to, "pull the master disconnect," to make sure they are in my house. > The LiFePO4 batteries have low source impedance and should work fine. > The spec on the pack is 30mΩ. That should produce a 0.9V drop at 30A. Not too bad. And no noise. A 13AH LiFePO4 (LFP) battery should run the 1500 for quite awhile. :-) And LFP batteries have really long life (~2000 cycles) making them ultimately cheaper than lead-acid. Too bad the up-front cost is so hefty. I had heard that the charging regimen for LiION was touchy but I have learned that LFP is almost exactly the same as lead-acid, i.e. constant current at a 1C (C=AH rating) to 10C rate (depends on construction -- most are designed to charge at a 3C rate) until 14.6V (for a 12.8V battery pack), then constant voltage at 14.6V until charge current tapers to 0.01C . As my lead-acid batteries bite-the-dust they are going to get replaced by LFP. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 [email protected] +1.767.617.1365 (Dominica) +1.931.492.6776 (USA) (+1.931.4.WB6RQN) _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
