Saturday, February 11, 2012

AM for the "BITX"

Nothing more simple than adding AM reception to the BITX transceiver, Right?

I was over confidence on this one, having done SSB I thought AM was going to be child's play..... a simple rectifying diode, a low-pass filter and that's it! I missed something in between for sure!
Was getting nothing at all, getting a whistle or getting to low sound...so after some days testing and a lot of soldering after I came up to my first acceptable version....oh did I mentioned that the idea was to use only the same values of components of the BITX V3 design? NO? Yes, that was the idea, even so I had to use 9 different values of resistors, diodes and caps (all standard values and no IC's or coils) but I also added airband reception in between except I'm using an external VFO. If the 2SC2570 can be used as VHF oscillator then the count will stay at 9....will try that in the future (7 for the AM part and 2 for the airband input filter).

Since this is the first working test, no schematic will be provided, I need to improve a little bit and try to reduce the number of different components.

Here's the lousy video, live audio was greater than the one captured on mic, I guess that if my mobile phone was a toaster all would came out burned!
Not all the components you see in the video are part of the design :)

video

Have a nice weekend!

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