The Bitx completed
My bitx project has been lying dormant for a couple of months now. I completed wiring about 2 months back. The transmitter was working properly. But the receiver was not receiving anything . When I tried to increase volume, it started howling. After initial testing, I became QRL with lot of other activities. This weekend I decided to look at bitx board again. I carefully rechecked all stages and found out that I had made 2 mistakes in wiring components , a 22 ohms resistor was in the place of 220 ohm and at another place I put a 1k instead of 100 ohm. After correcting the mistakes I fired up the receiver , I could hear some CW transmission around 14.01Mhz. When I increased the volume, the audio stage was howling. I decided to discard the audio stage and build a new one. I bought a small audio module form local market for Rs 25 and fixed it to the board. Now the audio is clean even when the volume is maximum. I am still not satisfied with the sensitivity of the receiver. I made the following measurements on various transistors today. The table of the voltages on transistors are given below. The transistors numbers are based on Bitx V3 diagram by OM vu2wmj Rahul.
BitX20 Voltage chart
Voltages on Receiver Chain Supply voltage 12 V. Transistor used 2N3904
Voltages on Transmitter Chain, Supply Voltage 12V
I think I need to verify the voltages with some other builder.