.............................................ICW............................................

Wednesday, May 9, 2012

600w 23cm LDMOS Amplifier Part I

 February 05, 2013 (see here update part II)
I am very embarrassed to publish it on my blog, but I must share the good and the bad.
I had disagreements with the 23cm JXX palettes Amps. On total of 6 that I received, 2 palettes were damaged. On the first one, 3 components were desoldering. The other, a copper circuit track ripped with Bias  pot. The box was clean, no damage at all and safe packaging.
Without any mods, only the bias current adjusted, In = 3,5w - 80w out!
A very high VSWR at the Input, each pallet must be adjusted by CMS cap, Input and Output.
The Bias currents must be checked.
The specifications label of each palette box mention 3,5w In – 205 w Out, 8,5A @ 48 Vdc
Further Mods at the In and Out, Each palette was tested individually.  The best one was IN: 8w, Out: 180w, the others IN: 9w, Out: 150/160w under 50Vdc
 The result is Unbalanced output in the Hybrid coupler’s.  And finally after mods and mods, on the bench, the total reachable power is 480w after optimization also of each hybrid coupler by copper straps.
I'm disappointed.
I've couple of MRF286S and I’m waiting W6PQL boards.

November 08, 2012: check and mod is necessary for each module, because high VSWR at the input.


 October 09, 2012: On progress.. ! 4 pallet I0JXX - 200MOD1296
Waiting for Heatsink's, Fan's,

 W6PQL Output Hybrid Coupler
IPP  Input Hybrid Coupler