[600MRG] WIMA capacitors AND substitutes

[lstoskopf@cox.net lstoskopf@cox.net]

OK, going to jump back in here.  I've ordered on of the Russian LDMOS 500 watt amps, water cooled.  Saves me from a bunch of mechanical work (have the tools, maybe not the smarts).  Tried to get them to sell me an amp with the Laird LF cores which I have instead of the 43 ones.  Didn't bite.  It should be here next week.  So will pull off the cores and replace with the Laird ones about the same size.  May use twice as many so it might work well at 136 kHz.  3 turns will give 520 ohms X2 at 500 kHz.       They put the blocking caps after the first set to take advantage of the higher Z there and thus lower current.   The schematic they provided shows 3 ea 0.1 uF 630 V caps on each side.  Pulled up the specs on the TDK C4532X7R2J104K230KA chip from DigiKey.  At 500 kHz ESR is 0.05 Ohms, Reactance is a couple of ohms and with 1 A ripple gives a 10C degree temp rise.  (at 136 kHz 0.5A gives the same 10C rise).  500 watts should give about 3A.  They use 3 in parallel on each side for HF so I'm going to use 5 or 6 to keep temps down.  Will let you know how this works out.  http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com

Not planning on running this much, at least until someone comes up with a way to measure EIRP! http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com

N0UU http://w7ekb.com/mailman/listinfo/600mrg_w7ekb.com