When this project was started I saw this part of the project as being the most difficult since it now has shifted from the realm of analog hardware to digital hardware and arcane software. Moving to the Arduino presents some obstacles especially to Old Timers (OT) such as myself whose exposure to digital electronics is of recent vintage.

But VU2ESE has solved the problem with his add on kit that costs $14. You get the hardware already built and it is a simple connection to the main Bitx40 transceiver board. He even suggests that there will be software that eventually can be added that will do more than just give you an accurate frequency generation and readout. Dual VFO's and SWR measurement are but some code that will soon be developed.

My Arduino and AD9850 code gets you the frequency generation and readout and that is it. Thus I will not be detailing here what I did but advise the reader to buy the VU2ESE board. By the way --my hardware cost more than $14 so that is another factor. Sure I developed the solution on my own; but that only was because the additional board was not offered at my time of purchase.

Size is another issue and a quick look below shows that my DDS takes up a lot of space. The "Add On" board is but a fraction of that size. So those wishing a compact rig tilts the decision even further to the add on board.

 

The VU2ESE board uses the Si5351 PLL (Phase Lock Loop) Clock Generator and is capable of generating three separate frequencies. Thus his board can generate not only the Local Oscillator (LO) but also the BFO (Beat Frequency Oscillator) frequencies. So another possibility is to remove the BFO crystal and use the Si5351 to generate the BFO and then you would have the ability to switch sidebands. While the convention has been to use LSB on 160, 80 and 40 Meters, the convention on 60 Meters is USB as is for 20 Meters and above. VU2ESE mentions the possibility of using the board on other bands, so the frequency agility and the BFO capability --all for $14 makes it a clear choice.

 

Notepad Text of Arduino Sketch
Si5351.h
Si5351.cpp
Rotary.h
Rotary.cpp
LiquidCrystal_I2C.h

 

OLED Display Option for the Bitx40 project!

OLED_BITX40 Arduino Sketch

Video of the Bitx40 with Si5351 & OLED

Below is a "paint by the numbers" wiring schedule of how to wire up your Arduino to the OLED, the Si5351 and the Encoder. An alternate is provided for those who want to have the line "Bitx40" change to read "On the Air" during transmit. This has no operational value other than to add a "cool factor" to your Bitx40.

If there is a desire to delve into the hardware and software I used then contact me at N6QW

 

Teaser

A Color TFT Implementation for the Bitx40!