Topics

IRF510 more Volts = more W? #ubitx

Jim McKay
 

I could not find the answer on the forum but I apologize now if it has already been answered. Noting the need for an improved heatsink/s. Has anyone done any experiments with increasing the PA voltage  (brown wire) up 24V to see if the output significantly increases. I did this with a BITX40 for a significant increase in W.

Jim

 

 

Doug W
 

If you access the list from https://groups.io/g/BITX20/topics instead of an email client you will have access to the search function.  Searching for irf510 24v will yield enough reading to keep you busy for a while.  Best of luck with your experimenting.  Should your quest result in releasing the magic smoke, fear not, a search for irf510 replacement will get you back to good.

Nick VK4PP
 

HI,
I did this last night with the uBITX, went from 13.8 to 24v. and only saw an increase of +-2w.

80m 24v=12w 13.8v=10w
40m 24v=7w 13.8v=9w
20m 24v=3w 13.8v=4.5w
10m 24v=1w 13.8v=2w

Also cause weird display glitched during TX....
Thoughts?
73 VK4PLN

Vic WA4THR
 

Very odd, but I am now seeing the same thing on my BitX40v3. On the test bench I was seeing what looked to be an output that increased by the square of the PA voltage ratio, but since packaking, shorter leads, some common grounds, I actually see the same or even less output at 24v than at 12v (or 13.8). I must have some wiring issue, but I did directly jumper the 24v to the PA and saw no difference, so ??

=Vic=

Nick VK4PP
 

Maybe the bias needs re-adjusting for 24v operation?
I really dont know much about the technical operations of these things, I am still learing...
I am tempted to replace the Electro caps with 35v versions and try maybe 30v in the PA... I have spare IRF510s... lol.
Nick.,

Rob Snow
 

I'm following this with lots of interest.  I still don't have my uBITX and probably won't until March or so.  My personal goal is for ~10W out 28MHz, preferably with some headroom if I wanted to push it or just for a margin of error.  To that end I've ordered extra IRF510s and some RD16HHF1's as I have poor magic smoke herding skills and even poorer PA skills!

-Rob