RF Output Increase Modification
This modification will allow the DX959 & DX949 to exhibit the RF output and swing of the Galaxy DX-series 10-meter radios. The board was always capable of this type of output; it was simply choked off by the design engineers in order to meet FCC 11-meter specifications. The first thing you need to do is turn up VR14 which is the AM high power variable. If you?ve already done the modulation improvements, you should be able to dead key about 8-10 watts and swing around 15 watts. 18 watts is probably the best you?ll get (using a peak-reading Bird wattmeter). Now, perform the following modifications:
Remove C218 (3pf) and discard.
Change C216 (470pf) to a 1000pf (100V mylar-type)
Remove C210 (470pf) and discard.
Remove C199 (560pf) and reinstall it in the C210 spot.
Adjust your dead key to around 5 watts. I was able to achieve average peak swing readings of around 35 watts. Depending on the audio input (voice or whistle), I was able to whistle myself to readings of over 40 watts peak! There was a slight decrease in modulation and it seemed as though I was really pushing it. I found that I was able to regain the modulation level by lowering the dead key (using the RF Power control on the radio face) to around 2.5 watts. This netted peak swing readings of just around 28 watts! More than enough given the fact that the modulation was over 95% and crystal clear!
