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I've purchased the 50-watt amplifier kit, to be built for 80m, and bought assembled the 40m and 20m amps from Ray, VA7SK (very nice solder job, btw); on 40m it certainly makes a noticeable difference

With those settings turned on, you will be getting about 20dB lower of a signal from your mic to the audio path (compared to when the setting is turned off) - so it may be reacting with other

Yes, checked 80m also and it looks the same. I’ll have to look at phase predistortion, it is currently whatever default is, on I assume? 73, Robert, WA2T

Hi Jim, L501 or C504 failure can cause these symptoms. ?Make sure to have about 2 ohms continuity on l501 at the pcb pads. ?It’s a little difficult to test C504 in circuit. ?These big

Too bad - I was hoping that L504 or L514 was broken, since they are so easy to replace. To test L501, the 330uH choke, I would first test it for proper continuity through the circuit card by probing

I noticed when I have EQ turned on, that I get choppy audio.? This happens when "Use EQ" is set to yes.? It persists while I am using the terminal or when I am out of the terminal or even when usb

Jerry, When I look at the uBitx LPF, its structure is the same as that of a "shunt first" input Chebyshev LPF.? Does that mean it shunts the high frequencies to ground instead of a "series first"

Hans, I'll do it and post the updated PDF. Now, please, go on your holiday! ? Dave WI6R [email protected]> wrote: -- *https://www.qrz.com/db/WI6R*

Adam, I would not do that as the low-pass filter is designed to attenuate the harmonics of 20-meters so the second and third harmonics of 40-meters will exceed regulatory requirements. Gary W9TD

Hello, I uploaded the charts of the simulation to https://github.com/dl4pj/qmxfiltersim The simulation now creates all charts at once and is easily customizable. Now I can start with my experiments

I'm one of those people posting about 20.? I re-ran all three calibrations for 20 one at a time and have been able to make QSOs I'm also having issues with sensitivity on 12 m and 10 m.? I didn't

Robert, did you test also other bands? Looking at your 40 m spectrum the signal outside the SSB chanel is only 15 ... 20 dB below the peak in the channel (around 7.152). Did you check the spectrum

Since I loaded the 1.01.003 fw the sensitivity on 10 seems to have dropped considerably. A loud signal on my 705 is barely readable on the QMX. Not sure why.

Evan, My guess is that this thread is looking at RF amps in general, and how to evaluate the voltages and currents that might blow the finals. Curious, on revisiting that uBitx amp, it looks like a

I rather like the Musk approach to innovating.? The big, establishment space company, United Launce Alliance, tries to get it right the first time, spends twice as much as SpaceX, but takes forever

Hi Adam, Im not sure. I’d have to check and see. I’m done with it for now. I tried to use it today and for some reason 10 meter sensitivity is not as good as it was previously. Not sure why. I

Hello, I was trying to connect a electret mic to qmx, I applied external 3.3volts to mic input and it died, won’t turn on , doesn’t draw any current. Any help would be appreciated. Thank you.

It should not matter. The reverse voltage is less than either value, and the forward current is very short in duration. The 1n4148 is the best choice because of the junction's switching speed. I would

I also built an adapter for mine.? In addition I reworked one of the Retevis mics.? I'll see which works/sounds best, they are kinda comparable in size. 73, Don N2VGU

What settings does the 60-15 have for 40m under the terminal band config?? ?I never use 11m and wonder if I can just fill that slot with the 40m config??