K2 Group, Would someone advise whether my Astron RS-20M power supply will handle a K2/100 with some basic SSB/DSP accessories? Thanks, Stu, K2QDE
------------------------------------ Runs mine just fine with "room to spare" in the supply capacity. Since you brought up the question of power supply capacity, let me address an issue about power supply ratings, especially the Astron power supplies, that has created confusion among many users. The Astrons are rated for Intermittent Commercial Service (ICS) -- OT's will know this as ICAS, Intermittent Commercial and Amateur Service but they dropped us from their acronym. That causes some to say we should never expect 20 amps from a "20-amp" supply. That's nonsense. You *will* overstress the Astron 20 if you set your K2/100 at 100 watts out, put a brick on the key, and walk away for an extended period of time. That is, you'll overstress the Astron unless the K2/100 emits smoke and quits first. Neither is rated for full power continuous duty operation. Operating 100 watts CW or 100 watts PEP SSB stays comfortably within the ICS rating of the Astron 20 supply. On many bands the K2/100 at full output stays comfortably within the 16 amp continuous duty ration of the 20 Amp Astron (the overall efficiency of the K2/100 varies with the bands, being best around 40 meters). When you derate your K2/100's maximum power output for high-duty-cycle data modes to keep it within specs, you are also reducing the current demand on the supply to keep it within specs too. Shoot, I even run my K3 and a few bits of accessories from my Astron 20 with no problems at all. My only concession is that on one or two higher frequency bands, where the K3 current level is higher than others, I run the power at 75 or 80 watts, max., to keep the Astron's self-protection "crowbar" circuit from tripping. Of course the difference in transmitted signal between 75 and 100 watts is meaningless anyway, so I don't mind. The Astrons are very well self-protected against shorts or very large over-current loads with their "crowbar" circuits. If you've never encountered it at work, should you exceed the crowbar trip point (IIRC, it's about 25 amps for the Astron 20) you'll suddenly lose voltage to the rig. The supply automatically shuts down to protect itself. Cycle the Astron power switch to reset it and you'll have full voltage back as long as the overload is no longer present. Ron AC7AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
