Thank you so much Julian. That really helped me. I had not seen Op Amps as a phase shifter so I got to do a little reading and calculated the circuit. I am getting even voltage across the I/Q pot so t

#40m #qcxmini #lpf

Colin, If you don't get a null, the phase shift network isn't working. If you've checked all the solder joints, the next thing to check is the voltage level at IC7 pin 1 and IC6 pin 1 while menu 8 is

#40m #qcxmini #lpf

Colin. The 10K pot is in parallel with R21. Newer schematics do show this as 10K. Total resistance will vary from zero to the parallel combination of the two so the 10K will actually give more range.

#40m #qcxmini #lpf

I have been getting good reception and adjacent channel rejection. I measured the pots tonight. I don’t fully understand the phase network. The high setting pot is set to 0k to get the lowest reading.

#40m #qcxmini #lpf

Those are excellent numbers on transmit. Plenty of cw with WES this weekend. How is receiver sounding? Find a very strong station, and see if you can copy weaker signals nearby. This would tell us it

#40m #qcxmini #lpf

Oh, one last thing, I am putting out 3.8 watts at 12v and 5.4 at 13.8v. I can not detect any harmonic with my main transceiver at all. So, that side of the circuit seems to be fixed.

#40m #qcxmini #lpf

Thank you Donald, I found some easy to make solutions for probes I can fabricate thanks to your suggestion. Julian, I have 10watts of 50ohm for testing. Hi Curt, I hooked everything up to an endfed an

#40m #qcxmini #lpf

Colin Well patiently sort it out. On receive calibration those pins on the trimmers are thin and easy to miss solder. Inspect it again. Also each pot is adjusted on a different menu setting. And note

#40m #qcxmini #lpf

And if you promise not to key it up, an 1/8W resistor is enough to load the LPF for Rx tuning.

#40m #qcxmini #lpf

Using an antenna to try and measure harmonics is bound to fail due to the unknown antenna gain, which will likely be higher for the harmonics. Find/build/but a suitable attenuator for such work. 73, D

#40m #qcxmini #lpf

I spent another hour checking things out. I finally decided if the 1st harmonic was that high I should be able to hear it on another radio so I moved every thing into the shack. (okay, my bedroom....)

#40m #qcxmini #lpf

I recently constructed a 40M QXCmini. I really enjoyed the process and am in the debug stages of the project. When I powered it up it was putting out 5.8W at 13.8 volts measured with a QRPGuys dummy l

#40m #qcxmini #lpf

If you look here: https://www.qrp-labs.com/lpfkit.html You will see pictures (4 of them). Top is finished product. Second row, left is the kit contents - shows PCB board. If your kit does not contain

#lpf

Help I posted below on chat not sure where this should go, excuse me. 20m LPF Subscribed Trying to build this kit, it is the LPF for Ultimate 3S. Not sure if I have the correct instruction,they seem t

#lpf

Thanks, that's what I suspected.

#lpf #u3s

It's been a couple of years since that build, but as I recall, W0 thru W3 are to connect the RF path without the relay installed. Just be sure to select band 0 to energize the installed relay. 73, Mik

#lpf #u3s

I'd like to initially test out the U3S without the Relay Switch board installed. I've soldered the Diode/Relay to the U3S for Band 0. I assume I can leave off jumpers W0-W1 and W2-W3 as long as the Ba

#lpf #u3s

Sorry my bad! They're there in the bag, my brain filtered out the different colour :d;

#lpf #20m

I find in the bag of 20m LPF for QCX 2017v2 two times 181 not 391 as indicated on manual https://www.qrp-labs.com/images/qcx/assembly_A4.pdf at step 3.12. I think this means 180pF instead of 390pF and

#lpf #20m

Il gio 25 feb 2021, 23:27 GIUSEPPE via groups.io <iw8rsb@...> ha scritto: hi Brad, hi Tony, it's always nice to know the lineages of your origins. What makes me proud of being Italian

#u3s #troubleshooting #help #lpf