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As has been said by one or two others as well as me, the package of the BS170 has a very high *thermal resistance* - 100°C/W (meaning that in free ambient air, the junction of the device will

Jim, Thanks for the update. You are drawing more current on TX, so that's a good sign. Are you getting spots on 10 meters with both the 10m and 6 meter LPFs in the chain? If so then things should be

WSPR isn't a communications protocol, you don't have conversations with it. And it isn't a competitive sport. The value in WSPR is to get a relative measure of current atmospheric conditions, to give

Al, I put the six meter LPF back in slot 1 and put the U3S in the lower part of the case and my harmonics on other bands are down and the output does not seem to be impacted. Best I can tell on 6

Hello Bertel, I have an ATU-10 and other ATU's. The ATU is not a problem, however the output stage of the QDX won't like wild impedance excursions whilst the ATU is searching for the best setting. I

The metal washer is NOT the heatsink, the washer only serves to hold down the transistors on the PCB copper with IS the actual heat sink.

The design of the PA in the QSX-Mini is not made for an on-time of 2 minutes at maximum power. The washer-screw heatsink can absorb some power, but it cannot get rid of it with convection or

There are two holes to the other side of the board, being a smart and lazy person I used them. So correct not soldered to the pads Current limiting, you are right, hopefully Hans will include this on

That's pretty clever! So those wires are running _through_ the board and not soldered to the pads? I like the 'both flavors of PTT on one connector, but shouldn't there be some current limiting on the

HOW TO GET PTT FROM QDX As promised, With Hans's help of course Do it on your own risk! Lot of silicon souls wasted, I take no responsibily, Most probably I might be mad. Don't listen to a mad person.

Well, FWIIW, I have been running my mini on 40 meters WSPR for about 18 hours. I did drop the voltage to around 11 volts. The case shows no increase in temperature for me. Similar performance with my

It comes down to - in all good conscience. I'm waiting on an enclosure from china. Is that really necessary? Let's start there. Also, do I call turkey a friend? Not on your life. Something is not

Mine, 40M- QCX+, has been sitting for a few months but no longer... I started with a bare board yesterday, working through the construction book which begins by winding the T1 transformer. That's a

Instead of all the hoohah about QCX mini overheating of BS170’s, if you are going to use modes that have 100% duty cycle, why not run the mini on 9v, the power drop at the finals will not be noticed

----- In a broader context, there are serious reasons to fret about this heavy dependence on China. Do an Internet search for “China bubble.” You’ll find numerous articles from a wide variety of

Hi measured spurious on 80M with leaded inductors: Used a 40dB power attenuator so -3dBm straight into to the analyser, fairly good results 73 Andrew

Well I've managed to get 20 & 40 working well but 30 and 80 remain virtually inoperative. I'll leave it as is for now because I use 20/40 mainly anyway. Over Xmas Break I will probably remove L12 an

Hi Hans, I realize all of this and know it’s unavoidable. Nonetheless, I still try to avoid buying from China whenever possible. Still hoping we can turn the train around before our kids are forced

for LPF: It will be much more cheaper using https://qrp-labs.com/lpfkit.html (these are for QRP, pls use bigger toroids, higher voltage capacitors) http://shop.qrp-labs.com/kits/ULPF Aliexpress (much

Hi. Thanks guys for all Your useful input about IF, WHY and WHY NOT using an ATU. I'll have to see what I can make of it. The little piece from QRPGuys looks interesting enough. Perhaps a good place