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If using an external speaker, make sure it has a stereo plug (not a mono one). I mistakenly plugged a mono plug external speaker in and it squealed.

Craig, Just to eliminate audio vibration feedback (microphonics), disconnect an internal speaker and try and external one a short distance away from the circuit board and mic. 73 Mike KF6KXG

11.5v should be fine, make sure it is still 11.5 when PTT is pressed. Quiescent IRF510 drain current changing somewhat as they get warm is normal The drop from 6w to 4w when V+ to the IRF510's is

Read this old post, you should be able to follow along with your vom: ? ??/g/BITX20/message/40808

Yes it has only been reported in two units so far. So it should not be a show stopper for anyone. The radio is usable and I will simply add an audio low pass filter if need be. For a radio aimed at

Just finished building my BitX40 after playing with the circuit for a few weeks. Early tests on mine suggested that using the small booster I have and raising the PA voltage from around 14 to 24 did

Hi Everybody, I just posted a file: kb1oiq_i2c_mod.pdf The document describes a hardware and software modification that I performed on my uBITX.? It converts the LCD to use the I2C bus, thus

hello;?ok I'm getting no 12 volts at D7 with ptt on and vom leads one on both des. sure do appicate all the help. so with no power at d7,where do I check next 73's de AC8XZ

I tried 7222 and it sounded like there was a station way down in the mud. I also tried to listen for myself on a number of SDR radios around the country and nothing. I will try back later. Ed W0OIC

Thank you for the clarifications. I’m all in for mods, changes and improvements to this kit radio because that’s where the fun is. But this post is cringe worthy if it affected the radios on a

7.222 seems clr. Listening for a few then I will call some. -- David ?N8DAH Kit-Projects.com ( http://www.kit-projects.com )

Hi! I have checking with a magnifying loupe looking for broken copper tracks or any strange looking components. I have unsoldered and redone t11 and t10 i have resoldered all bits that looked poor

For anything this complicated, a few units will fail in the field, if only due to rough handling through the mails. The uBitx count is now up in the thousands. Most uBitx's just work as delivered, no

The CAL VALUE x 100 represents the offset (in Hz) that we need to apply to the nominal VCOA frequency (875 MHz) in order to get the correct output frequency. So the ppm (parts per million) value can

My idea would be to divide and conquer. First step, see if you get proper quiescent currents through the IRF510's. Put an ammeter in line with 12v supply for the IRF510's, turn RV2 and RV3 to the

Get well soon John. Listening to the top end of 40M right now and it's chock full of AM Rally stations all over the place from 7.250 to 300. I'm QRV on 7.240 for traffic and a possible substitute

I’ve been following this post. What does this all mean for a beginner who is waiting on a uBitx? Is there a problem with original design? Are these strong audio tones noticeable or interfering with

So in order to have an oscillation, you have to have a closed loop with a gain greater than one at the oscillation frequency Since your squeal begins when you turn the vine control up, and then input

I am sitting here reading some of this information and studying the new technology.? When I was young (at leas 50 years ago), solid state technologies were either in their infancy or still a dream.?

Where did mine December 15th and got it about a week ago Andy KM4TRT