I have 3 of the 5 watt PA units and are of simple build. For the life of me I can only get one to work. There are 5 #105 capacitors, one 3.3k resistor, one 78L05 100ma voltage regulator, a FT50-43 tri

Have you got a short in your left menu button

#u3s

Paul I have run mine on 40m WSPR for days and days and no issues…supply was 13.8 volts…even the voltage regulator did not get that warm. Vernon

Thanks all for your input. I did find them at Kits and Parts and ended up buying a few other things as well. Shipping from there is $11 versus $20+ from some of the others. You have to remember that i

Thanks Karlis, Arrow does have them but the shipping is 3 times what it is from Digikey. You only get free shipping on orders over $50 now from Arrow. Vernon

Can a IRF540ZPBF be used to replace a IRF510. I get my parts from Digikey due to the low shipping cost and 2 day delivery. They are out of stock on the IRF510 and have suggested the IRF540. I am far f

Hi all, I have two full build PA’s that I just cannot get to work. If I remove the components as stated in 3.3 that are replaced by jumpers to bypass the power modulator circuit and leakage gate circu

Allison thanks… I guess I may have worded the note not quite right. I am looking to have the same output from each band to drive an amp. Presently my single BS170 will give me say 125mW on 10m and 350

#u3s

Hi all, Has anyone been able to successfully balance by whatever method the output of the U3S so that the basic output is the same on 10m as 80m. Is it possible? Vernon

#u3s

Hi all, I have noticed when running my U3S and 5 watt amp on 10m that I get a Calo when it goes into calibration rather than the plain Cal. Is that due to RF getting into the GPS and causing it a bit

It's on the U3S Jeffrey. Sent from my Samsung Galaxy smartphone.

Sorry I should have included the message from Hans. See message # 23905 in the qrplabs section of groups.io Vernon

At the end of the text insert *150* and that will give you 15 seconds of tone. The number is however long you want the tone. Vernon Sent from my Samsung Galaxy smartphone.

I found my answer to my post…thank you.

Here is what I want to send…Hans had given me a command to enter at the end to insert a tone for however many seconds you want and for the life of me I cannot remember it or find where I wrote it down

Hi all, I run a couple of the QRP Labs on different bands and have found the output on say 80M and 160m were very good. More than 5 watts. In fact on 80m it will bury the needle on my Oaks Hills set o

Are the specs the same for the 4.7k trimmer in the U3S the same as the 4.7k trimmer in the 5 watt amp. Vernon

I removed 2 turns from the toroid and no appreciable difference in output. I thought that maybe it would move the performance level up the band a bit giving more wattage to 20/30/40 but all are still

BTW I built this amp using the simple method so not much on the board. Vernon

Thanks guys…no cracks found. Gave all the pads used a touch with the soldering iron as well. If I run 40m/80m FSKCW into a dummy load with the U3S bias set so that I have 2 watts output on 40m when it