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Unplug the vol control from the board and see if touching the pin that would connect to the wiper gives you noise. That isolates the preamp from the circuit. If you get the noise you used to get, look

Jerry, now I think of it- I have a much better idea: at startup, initially enable the pullup at A0 and check if the PTTsense is installed. Then disable the pullup, like so: //configure the PTT SENSE

Here's what they say in the Arduino docs about the pullups: ----------------------------------------------------------------------- On the digital pins: There are 20K pullup resistors built into the

No schematic Karl, but it's quite simple. A regulated 12 V supply for the BitX and prior to the regulator is the feed to the PA. Because of how I have it set up, when I turn it off I turn off power to

I think it is the "inline" reference that is causing the confusion. Bill, VK7MX

Thanks Jerry. I didn't know it was possible to track it once it left India. I'm a long way from a small rural post office but the one in my neighborhood isn't usually too busy these days. I'll ask

Farhan, thanks for replying, thanks for your patience. ? Here are the responses to your thoughts: audio preamp might be busted. *Uh-Oh! ?Q16? * the LM386 seems to be working (from the test that you

Yes I had this problem too sometimes, it was caused by RF due to poor SWR. Make sure your SWR is OK and that everything is grounded properly. Perhaps your cheap paddle (its cable) is not shielded or

Some do take longer than others to arrive: ? ??/g/BITX20/message/22442 This tidbit from the first post in that thread might be informative: "I had an email exchange with hfsignals

Jerry, Correct, we need the pullup on A0 for reasons of backward compatibility. At startup the firmware detects whether or not the PTTsense line is installed. When the PTTsense is NOT installed, input

Hi Jack, I'm still waiting for my BitX kit (I fear it may have gone missing) but I have all the parts for the VFO and will start construction using the new manual. I would like to vote for split mode

Not sure if anyone else has noticed anything similar, but here is an interesting observation. I have a cheap mfj travel paddle I was using to test the qsk and keyer functions. I'm using an end fed

While reading this thread, I am sure that many builders have wired their BITX-40's for dual voltages.? If you have, I would like to see a posting here on just how you accomplished it.? This would

Ah, that explains it all. Glad you found it, thanks for letting us know. And now... happy BitX-ing! 73 Allard PE1NWL

**SOLVED** Yep, it sure was a short between A0 and A1. A bit of sloppy soldering on the Arduino MCU. I could have sworn I checked earlier, but must have overlooked this tiny spot. Thanks again for all

Paul (call sign?) wrote... The post at /g/BITX20/message/23973 that Jerry pointed out pretty much says it all. Keep in mind that there are two places on the main circuit board that

audio preamp might be busted. the LM386 seems to be working (from the test that you performed). check the voltages around the audio preamp's base and collector. if the LM386 gives you noise, does the

Bump to top! -- John - WA2FZW

When I first set up the Bitx40, it did seem to receive OK. ?Then there began to be various, random “drop outs” into silence.? Cycling the power usually got it back.? Then one day it went dead

From what I can tell, everything checks out OK. Voltage on A0 attached through 10k resistor to regulator output is ~1.22v RX, 5v TX. Regulator pin 1 is 0v RX, 5v TX. Regulator pin 3 is 0v RX, 12v TX.