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Dan, The Zener diodes suggested have about 150% the capacitance of the TVS. The capacitance is measured at zero volts, at 9 or 12V, the capacitance is about 1/4 the value at zero volts. Each BS170 has

No whining, Emory! Old guys rule...IF they can put a QMX together and it works! -- 73 Karl KI4ZUQ

Real men use mode B.... Not-so-anonymous

EvanReally appreciate the help. As soon as I read your email, thought why didn't I think of that. Had to take qmx all apart set brightness and it works fine. I am amazed felt sure it would not work.

Jim, The IRF510 is? 100V device.? FOr PA anything under 24V is safe as it goes. That may increase power out but the amp gain does ot change greatly. The 2.5W from the driver is likely the limiting

https://worldradiohistory.com/UK/Practical-Wireless/80s/PW-1989-11.pdf https://worldradiohistory.com/UK/Practical-Wireless/80s/PW-1989-12.pdf Good experiment showing HF incoming polarization

Regarding the use of a Pi 3 that is not a good idea. One of the WSJT-X developers posted a note in the last year or so stating that a Pi 4 does not have enough compute power for FT8. Does it work??

i did not encounter this with my QMX build, however,I'm sort of a belt and suspenders guy. So I lined the bottom shell of the case with PVC tape before assembly to avoid shorts. -- 73,

Tank you very much for all answers, I will do as advised and keep the attenuator, particularly in the light of the fact that it also servers as a matching network, as pointed to by Bojan.

Perhaps unrelated to the issue originally described here, and completely anecdotal, but with my QMX I've experienced much more lag/oddities/keying errors in IAMBIC A mode than in IAMBIC B mode. ?Has

Hi all. As a CW operator, the more important parameter is key down to start of audio tone. The start of RF envelope can be delayed significantly from the start of the audio tone (even 13 milliseconds

Definitely want to check Q103/Q104. My QMX kit was shipped 8/24, and it had the short. I haven't started building yet, but I did fix the short by using a hot air rework station, and nudging over Q103

Thank you for your assistance Jim and Jack. The ham radio community is fantastic. Yes, it can have warts at times, but overall it is great. Jack, I very much appreciate your gracious offer, and I am

Hi Emory, Have you tried adjusting the contrast potentiometer???Start with it almost fully counterclockwise. 73Evan AC9TU

New build of QMX.? I think firmware loaded ok for initial load.? Screen lights up but its blank?? Device manager shows com port and audio shows 2 audio devices for QMX.? On and off works but again

Hey Bob, Yes in semi QSK. I will experiment with that when next in the shack. Cheers D.

Hi Hans, I can't speak for Don of course, but interested in his reply. I can only say I, and a Facebook friend,? have noted a delay between key pressure and sidetone which is causing us to make

Are you in QSK "mode" or ??? (i.e. Perhaps the "semi-qsk-mode" delays the sidetone ....<- Just a wierdo thought on my part, as this should not be the case.....) es vy 73 om de "baab" w9ya

Hans, You are correct!! I should have checked my notes on the QCX. Mine ( v1.00f, and v 1.04) both measure 1 millisecond or less on the bench just moments ago. So very sorry. I cannot re-test the QMX

Mornin' Jim: How many do you need? Just send me your mail address. Jack, W8TEE