Hi charlse, I had same problems. I wrapped that toroid in Kapton tape. I dont think you want that scraping in and out, shorting out on the case. Later i took the tape off the inductor and applied it

Ryan, In the PA_Assembly_1.04 manual is clearly stated: "....tests were undertaken by Allison KB1GMX ...... Gain: 26 to 28dB, with +/- 1dB gain flatness over the range 1.8-30MHz" Screen dump of

I don’t know. I am just a 77 year old retired medico and bought three of those piles of junk. I recently took four days building, after reading the directions three times (the correct directions

Paul, You might check the BPF switching. On RX the selected LPF should have nearly zero volts on everything. The unselected ones around 4.4 volts on everything. The outer connection of each switching

Hello. QDX is sold. QDX ist verkauft. -- -- de DO7OO ex DE8MSH

Add a .01uf cap between pins 1 and 2 on earphone socket pins on back of board. Make sure it lays flat to clear case. Takes care of the stray RF issues in the audio.

As pointed by Don N2VGU in #82726, NanoVNA is not able to fully drive the amp so the impedance measurement is inaccurate. I just did that and I know for sure driving it with 705 or KX2 @ 4W would have

What makes you think you did something wrong? The output isn't linear across all bands. The higher bands definitely need more drive. What you're displaying looks pretty normal to me. If you bump up

Hi Bill, Have you discovered anything interesting with your squealer ? I'm really interested because I've come across one myself a unit that I'm repairing for a customer. It's a 30m unit, but I

Here is what I have and it's cheap and they provide software for Windows/Linux https://www.pololu.com/product/3172 W4GNS

I've built both the QCX Mini and the 50w Amp. I got round to testing the power outputs and was a little disappointed. The QCX Mini:battery voltage QRP Mini 11.34 (3xLithium 18650's half charged) Diode

The supplied IC''s work great if you follow the directions. A small piece of paper is provided to clearly replace IC 10 and IC 5. Not IC 6. I regret you are frustrated, it is understandable, but QCX+

Greetings all, As I near the end of a 50W PA (40m) build and am beginning to fit it into the case, some additional questions have been raised. To whit... 1) Referencing the picture below, when I go to

Martin: as you might have guessed already vents and rants on Internet forums are counter-productive as they don't usually generate positive responses. From your previous post about your QCX problem it

...and here is a great guide from Alan G4ZFQ. 73 Ian VA7ITM

Thanks Evan. I did some calculations with it. Something doesn't seem right. With 330/22, assuming the amplifier side impedance is 50ohm, the transceiver side should see impedance of 55ohm so the SWR

1Here is a link to a Pi Pad calculator that will tell you the value for a given loading (mostly 50ohms): https://leleivre.com/rf_pipad.html It calculates a 3.19 attenuation loss. If 20% resistors are

Hi Giuseppe, I don't know the "type" of interference unfortunately.. From TinySA, it's a broadband S9 signal from 14MHz to almost 28MHz, so perfectly blocking all my daytime HF activity... Yes I do

If it's fine with a dummy load then, yes, it's a common mode issue. Describe your antenna and feedline to the rig. -mike/w1mt

With a dummy load on it sounds normal. I would suspect a common mode issue on the antenna leads but my QCX-40M rig sounds normal with the AGC on. My main rig is a Yasue FT-450D and there is no