Hello Yannig, This is a good read to start with: https://wb3gck.com/2020/03/10/the-doublet-revisiting-a-classic-antenna/ The Z-Match tuner is also mentioned and a hyper link is available. You might lo

Hello Yannig, Presumably I also need a tuner ? Yes, that is the only downside, but considering the same antenna can be used on 40, 30, 20, 17, 15, 12 and 10 meter it is certainly worth the extra effor

Hello Yannig, For an antenna you might look into the doublet, fed with open feeders / ladder line. I have used one measuring 2 x 7 meter, which worked very well on all bands from 40 to 10 meter. This

Hello Bert, Regarding the LDG Z100 plus, I have been reading the manual and I have a question. My shack is in an upstairs room and the feedline entry of my antenna is in a fixed cupboard in the living

Dave, It took me two days on and off and a lot of headscrathing before it dawned on me that C22 was the culpritt. I checked it out on a capacitance meter and nothing was wrong. I found the fault by co

Hello Dave, I had a similar issue with my QCX+ for 80 m. To take a long story short, the fault appeared to be C22, which suffered from a minor leakage. Over time this pulled the input of IC10 low, fir

Alan, You might have a look at polymere self-resetting fuses. These don't break the circuit, but develop a high resistance when a short happens. It limits the current and protects the power supply. I

#qcxmini #magicsmoke

Tony, I have used my QCX+ 40m for WSPR, throttled down to 1 W In my case I have 1 W output with a supply voltage of 8 volt. This has been running for weeks, transmitting every 10 minutes without any h

Laszlo, To block rf getting into the QCX, a common mode choke between the QCX and tuner might help. Ten turns RG174 or RG316 coax on a FT-114-43 toroid will do. 73, Roelof, pa0rdt

Hello all, As far as I know the same rules will apply in the EU starting mid 2021. On another note, when I buy from Mouser in the US, I have to pay 21% VAT, which is the same as when I buy goods in th

Hello Sergey, I had a similar issue with a QCX+ with the same voltages at IC10. IC10 was not at fault, but the coupling capacitor between the volume potmeter and IC10. This is C22 in the QCX mini. Whe

Mike, As I had a problem with the audio in a QCX+ 80m, I removed IC10 and mounted a socket for easy repair. IC10 was not at fault, though. Before mounting a new LM4562, I also tested a NE5532 and as f

Hello Mateo, I had a similar issue with my QCX for 80 meter. The voltages on IC10 pin 1, 2, 3 and 7 is too high. It should be about 5.6 V. In my case this voltage drifted up over time until it reached

Al, My QCX+ for 80m gave an output of 2.5 W with 12V and 3 W fed with 13.8 V, which is a bit low. The voltages are not corrected for the voltage drop over the reverse voltage protection diode. I remov

#qcx #lpf

Hello Hans, Thanks for the explanation and regarding the Goerzel filter, I thought so. For the time being I will leave the sidetone at 700 Hz. 73, Roelof, pa0rdt

Hello Randy, I am in the same league and prefer a low side-tone. The audio filter is designed by NM0S and the center frequency can be changed per this table as found on webiste the Four State QRP Club

Hello all, My 20m QCX-mini arrived today in good order. After seeing photo's of boards with damaged parts here, I was quite eager to put my mind at rest. Using a head loop and strong light, I inspecte

Hello Sherley, expensive and it's overkill for most individual builders. A lower cost version is the Xytronic LF-3000. I have been using one for over ten years now and tips, replacement irons, etc are

#building

Hello John, Further to the 'unstable' voltages on pin 11 of IC3, I gather this is caused by the on / off keying in rhythm of the Morse. A digital multimeter will show a kind of average. Using a VOM wi

Hello John, Have you measured the voltage at pin 11 of IC3, whilst in straight key mode, aka sending a constant carrier? 73, Roelof, pa0rdt