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In talking with someone about Bitx40 mods, someone said there is a front end protection diodes hack; I have not been able to find any details on this mod so far, does someone have details findable?

Keith , Farhan has used a dual series diode pack. BAT54SL. The device has better matching of each of the diodes. Thus he did not use the balancing trimm pot. if you have a pcb compatible,

You will need to tell us what you are doing before we can tell you that you are doing it wrong. Could move the VFO from the Raduino standard of 12.0mhz-7.0mhz = 5mhz up to 12.0+7.0mhz = 19mhz This

HI, I have been working with some code - author - PD8W This project uses an atmega 2560 with a colour display and a Si5351 DDS I am able to use a 2.8 colour tft display with a rotary. The bitx rig

If you haven't worked on the 5V regulator on the Raduino, now may be the time. I put a diode in series with a 47 Ohm resistor to the input of the 7805. then I added 100uf/25V on both the input and

Hi, I would hazard a guess as either poor power regulation or feedback. Either might be caused by high resistance in an earth connection. Cheers, Will

Hi Jerry, I recently added the tx mod to my latest Bitx40 (3rd). So far of all the tx pop mods, this one has produced the best results. The noise i refer to is a screech or loud click / pop when tx

Ok so after further testing i was getting reports that the audio was good but then others were saying i'm still muffled. ?I have tried 3 different mics including the electrec that came with it and

Jerry KE7ER wrote... Thanks for pointing me there. I don't have any complaints. I was just curious if changes were documented. The more I look at the schematic (& the actual board) the more I

Sorry about that I never got around to finishing the schematic to match what I built. I kinda figured no one else would look at it. C4 and C8 are both 2.2 mfd caps. R7 is a 20K pot that sets the

The 45mhz crystal filter is likely rather narrow as well. Perhaps have an option to replace the 45mhz crystal filter with something like this:

Joe, Please tell us a bit more about what you figured out. Does this cure the pop in the headphones when you press PTT?? What I would call "tx noise" is the brief outgoing carrier, which is a

Hi, I also tried your circuit for the tx noise. It works very well. I have tried several but this had the best results. I use it in conjunction with a relay

An ADC on the audio with a simple program to do peak detection might do about as well as the ad8307 on the 12mhz IF. But the ad8307 will give better dynamic range (unless you have an awfully nice

Nope. Here's a list of the minor differences between the Bitx40 schematic on hfsigs (no change since raduino introduced in Dec 2016) and what gets shipped: ?

While I'm waiting for the replacement IRF510, I was looking around at the circuit board on the BITX40. It was purchased June 2. The schematic at hfsigs.com shows a pot R106 between D15, D16 and the

Maybe switch between the 45khz crystal filter, the 12mhz crystal filter, and analyzing the audio with an ADC. Jerry, KE7ER

you could just do rms of the audio. the main challenge would be that given 3 khz bandwidth, the 30 mhz scan would need a reading every 1.5 khz. that means, 20,000 readings for the full scan. it will

If I were to create a pcb for the uBitx, it would have pads for an optional ad8307 (or ad8310) after the crystal filter, just before the demodulator. ?Drives an ADC pin on whatever processor you

I just ordered 2 of the ones with the display them China things don't last long I have found so I will have a back up they Look cool anyway