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Hi Ken, I read your earlier post - and noted your drift was minus, where mine is positive. I think it's a worthwhile mod, the power out on my low bands QDX is a good 1 to 1.5W higher than my high

'if it ain't broke, dont fix it' applies !! Hi Steve, I posted this before but no-one commented….. I rebuilt my output transformer in my QDX as mine was originally wound for 9v, then modified, in

I’m going to guess that it will not work without the boot loader. As this code is the only thing that prevents cheap Chinese clones from flooding the market, Hans has previously stated that he is

Hi all, I've just completed my second QDX - this time using the RWTST method for T1. Just over 5W or so on bands with a little compression of some LPF inductors, so all good. On some bands I need to

TNX? Mike Good to know Hope I 'NEVER' have to go there oops never say NEVER hi HI ! tnx agn 73 John N3AAZ

Hi, @kees: Good eyes, but no: no uncut legs... just bad light for a photo @chris: I don't think so... the paddle attached is a simple passive paddle and has no active components. USB was not

I've been wondering the same thing Hans.

I use an RPi4-2gb over SSH and VNC for WSPR decode on all bands 630m to 6m and am regularly in the top 30 of the Worldwide Reporter ranking WSPRNET. ( http://www.wa2zkd.net:8088/yesterday/ww.html )

For probing SM IC's I use dressmaking pins with the test leads soldered to the pinhead and then insulated for most of the pin's length with Heatshrink. To remove the FST chip or the 74S74 I use a

Rob, WSPR frequencies are used for FST4W. It was originally intended for use at LF with the long modes in particular. Now it is used for research on all HF bands. I've received some 10m signals from

What frequency are you running FST4W on 20m? I only see references to frequencies below 2 MHz? Also, I started monitoring FST4W on 160m and there are 2 stations, but one uses USB and the other is

If you must cool something, cool the transistors and the driver instead. They would like that. Transformer performance actually increases until it suddenly breaks so it won't be very useful trying to

Thanks for all the tips. They got me probing in the right direction. Turns out that the output power setting in the software had altered and was below 100%. Changing that produced a good 4.67W output,

I'd still try cooling it to see what happens. Sometimes my view of what's significant needs to be "adjusted" by experience! ;-)

Different story. Unless the ferrite core reaches about 150C the transformer will not lose performance. One exception is if the temperature melts the insulator on the wire. (I melt some feedline

Hans, i blew up my QMX IC 203 . I stole one from my other kit and installed it. I also order two more qmx's I ordered 2 spare, STM32F446VET6, chips from Mouser Electronics in hopes of fixing the blown

Really? I thought this was the opening topic: /The power will stay up for a while until it gets really warm./ :-)

If the surface temperature is up to about 80C or so, I wouldn't worry about it. It's best to keep at 70C or below, though that alone doesn't kill the transistors in such a short period of time.

Yes, loss in the transformer turns into heat. But that's a different mechanism than what I think is stressing the finals.

I'll have to find some freeze spray. Would love to use it to identify what the heat is affecting. 73, Cliff, AE5ZA