Microcontrolller work

May daily jobs involves programming small processors. So I don't want to program at home.
However the transceiver requires a microcontroller so I did some programming anyway.

Stuff I use
-PIC 16F877 microcontroller running at 20 MHz.
-rotary encoder, LCD and several switches.
-2 x 74164 shift registers to select the band. No more IO pins were available.

Features so far:
-Tune the HF band an 160 Meter. The DDS is used as the LO.
-Basic RIT functionality
-Band selection By pushing a button and rotating the encoder. Band is outputted using the shift registers. They drive a relays using a transistor.
-Mode selection LSB,USB and CW by pushing a button an rotating the encoder. An mode dependent offset is added to the DDS frequency.

Features to implement.
-TX and RX handling like adding RIT offset while receiving. Maybe TX/RX in display.

In this state the controller and DDS should already be usable. I have not used it as a LO yet. I have to make an amplifier and a filter for the DDS output first. The frequencies out of the DDS seem OK.

Now I am working on the lowpass filters.

Some progress

Progress is slow on this one. Besides  did not update this blog regularly.

I did a few things though.
-If strip is working. But it needs some finishing touches, like using varicaps instead of trimmers for the band pass tuning.

-I found an enclosure for it. I bought it from a ham who was quitting the hobby.

-On  ebay I have found cheap AD9850 dds modules. I have bought a few. One of them will be used as synthesize for this project. I know that it is not ideal with respect to phase noise. I can add cleanup oscillators later.












I made a controller for this board using a PIC processor. Now I can generate signals between 0 and 40 MHz

A band pass filter is almost ready. I had top skip 160 meters as it did not fit in the filter enclosure (tin box).