Re: V4 TX problems and new finals #ubitx-help


 

Harrr! Congrats Don! make mine a Bud !

I nominate you the next script writer for Star Wars.

From your pic of IRFs - keep each heat sink from touching the other. If they touch you will not have fireworks but simply NO OUTPUT
power! They look dangerously close! Probably they were touching!

I recommend a larger single heat sink and insulation washers and mica or rubber for IRFs, then no need for fans.


Cheers
Raj

Emacs!


At 19/12/2019, you wrote:
Evan, Jerry, Mark, Raj, Anthony, & Co.  First a million million thank yous. I'd buy you all a beer or three. If you ever make it to little Vienna VA, I'm good for it. hahaha.

I tested the TP7->TP8 for continuity, checked r97/r98, examined the "functional integrity" of the RV2 & RV3 (I looked at them with a serious expression), did the bias setting process about 5 times just to prove that I could get +100ma consistently on each 510, and set the drive pot to produce 10w on 12v on 80m.  Then I tested and tested into my dummy load. I had RF power. YEA!!  With success at hand, I immediately took out the functioning ebay 510s, and replaced them with the real deal Mouser IRF510s. Did it matter? Well, no. But it made me feel better?  And I then did all the checking/bias setting over again. I still had RF power, even with the new new 510s.  [I got 10...just saying]

Then I moved up to +15V on the brown wire. I got more power. Then +20V.  And I got even more power. I was mad with power! How much power you ask? 30W on 80m. And the spectral purity is only sort of marginal. hahaha.  I keep it below 30w...mostly...I try to keep it down...really I do...but sometimes...I ...just...can't...help...myself....ahhhhh.

I felt like Dr. Frankenstein..."it lives!!!"

The hormonally excessive large heat sinks got thermal switches to drive fans. The case got cut to hold the fans. Power was supplied to the fans. I was ready to conquer the world!
[] []

Except the fans didn't really work.  The thermal switches were "on" all the time, the fans even with soft mounts made a racket, and the stupid fans would clog every time I hit TX.  And then they died. Maybe cause I paid $1.99 per fan?

So I need to redo all the fan business.   And I didn't think to test the thermal switches ahead of time. Normally open? Normally closed? hun? what? Such an idiot.

But, back to the gorgeous heaven sent RF of life. The results?  WSPRnet says I am getting out to the world! It lives!!
[]
So with the awesome power comes awesome responsibility. And the PC crashes on 30m where the antenna SWR is a bit "sub optimal" aka near infinite. So I'm adding ferrite beads everyplace, improving grounding, and finally turning down the drive on 30m.

Still with me?

Well thank you all so very much. I owe ya.

If I were more in touch with inner myself (which actually sounds a bit repulsive, when you think about it),
I'd say I love ya, but really, that sounds a bit much.

Don
km4udx

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