开云体育

My impression is, we are expecting too much from a "24bit USB soundcard". The PCM1804 is a very good audio ADC, nonetheless it has a dynamic range of 112dB, equivalent to "only" 18.7bit resolution in

I guess the concern is more about overall stability, regardless of the band. E.g. I was attempting control via hamlib today and the QMX instantly locked up. Reproducible. Didn't realize that the

I will consider reasonable offers too!

Hi all I both agree, and disagree, and with everyone. I do see what Mike's saying. QMX has a 24-bit USB soundcard, and WSJT-X uses only the top 16-bits. It's a 16-bit sound device and the

Same AGC discussion has existed among CW operators, too, especially for pileup conditions. Strong AGC is easier to operate but softer AGC or no AGC is better for picking up weaker signals adjacent to

Hi Timothy, Thank you for your words. It seems to me that this topic is not so popular among hamradio.Most (all) amateurs are happy with a "classic" AB B or C class amplifier which such a lot of heat

This problem just occurred with my QMX. I had removed the power connector from the radio and reconnected and the radio was dead. Upon troubleshooting, I discovered the shorted 5.6 zener diode. I could

I totally agree with Tom. I also have an Icom 7300 which is a very good radio. It has an AGC that is normally on for all modes, SSB, CW and digital. I found that turning AGC off for digital was much

Hans! Thank you for your clear answer!? I will be ordering today.? Looking forward to getting on the air. Thank You, Burt K4SRQ

I would not use AGC for FT# or other digital narrow band signals, one strong signal on the channel ruins the rest of the incoming weak signals. 73 Ton PA0ARR

Hello Mike Yes OK I see... yes true, QMX outputs 24-bit audio, but WSJT-X only consumes the most significant 16-bits. So perhaps you could argue for a slow AGC even for Digi. Certainly a lot less

Yes. See assembly on page 22 ( http://qrp-labs.com/images/qmx/manuals/assembly_1_00j.pdf ) -- Gyula HA3HZ

Hello, The 2 390pF ceramic capacitors are missing from my kit. Unfortunately not a value I have in my personal stock of through hole stuff, I want to source them locally. Anything special about them?

The QMX has higher integer precision than wsjtx uses. On a quiet band with only very weak signals present, wouldn't AGC give wsjtx more bits of signal to work with (i.e., higher SNR)? 73, Mike KK7ER

Hello Burt QMX contains internal buck regulator boards for it's internal 3.3V and 5V rails. These boards are available as spare parts on the QRP Labs shop. You don't need to purchase these boards when

Hello, I am getting ready to purchase the QMX.? From all I have read, the rig is not complete without a buck converter.? I would perfer to run 12 volts as that is what all my batteries are.? Some

Hi Nic Why is there ever a need for AGC on FT8? 73 Hans G0UPL http://qrp-labs.com https://buymeacoffee.com/g0upl

Ted, I did not try a single diode. Since this is an AC audio signal, I believe you need both diodes. I used diodes I had pulled from a dead commercial circuit, but no reason why you can't use ordinary

I did one POTA activation with my QMX when I got it working and it was great but these two features are a must. The signals were so strong my external speaker would get very distorted (even with

Dan, Did you try this with one diode in each direction first, and then decide to double up based on the results - or just go large from the start? I'm curious about the difference between one pair vs