There was a mistake in the source code I had originally uploaded that effected the offset frequencies, it has been corrected and the file has been re uploaded. Sorry for any inconvenience.

@travisowensinstituteoftaek8069

9 ай бұрын

I have downloaded the Arduino sketch for the dds-vfo project but for the life of me I can't get it to verify with some errors... I have worked with the sketch and got the library added and defined some things but I just can't get past the si5351 stuff... any thoughts???

@CircuitSecrets

9 ай бұрын

@@travisowensinstituteoftaek8069 The library is the Etherkit Si5351. It is under the etherkit series of libraries in the library manager inside Arduino. I hope this helps you get it working.

@travisowensinstituteoftaek8069

9 ай бұрын

Wow... you even say it many times in one of the videos I heard it but didn't listen...lol... THAT WORKED!! many thanks

@CircuitSecrets

9 ай бұрын

@@travisowensinstituteoftaek8069 I am glad it worked for you!

Dear friend this project works well but i need the rx offset frequency to be +455khz on the channel frequency. for example 27005khz+455khz=27460khz signal for the mixer. how do you modify the sketch to achieve this? Thanks for the reply.

@CircuitSecrets

Жыл бұрын

There is no secondary oscillator or reference oscillator as it is usually called in your radio? If you need a direct positive offset the code will need to be changed because it was built with the assumption that a reference oscillator would be used for mixing or it would be used as a direct crystal replacement for a typical crystal based CB from the mid 60s, so it only supports a typical offset form that subtracts the reference frequency from the target frequency. What model of radio are you working with? Typically the receive offset is lower than the operating frequency. As an example a C.B. that is operating on 26.965 MHZ will have a receive offset of 455 KHZ so the VFO will need to operate at 26.510 MHZ. With a radio that uses a single crystal for transmit and a single crystal for receive and no mixing other than the IF stages of the receiver the offset will be 0 for transmit and 455 KHZ or 45500 in the source code for receiver offset.

Can you change the code for the 630 meter band? I know I cant, but it would be nice for my 630 meter transceiver. Crystals are hard to find.

@CircuitSecrets

Жыл бұрын

I built the whole thing around the notion of using it for 10 and 11 meter. It would take a fair amount of work to convert it to that band, but it should be possible. I give a very detailed explanation of the operation through the I2c series, that and the source code should make it fairly straight forward to modify. Give it a try, I have faith in you.

Will this work on an arduino nano?

@CircuitSecrets

Жыл бұрын

Yes, but the pin out is a little different. Make sure you use the correct pins for I2c and pin 13 may need a different resistor set for the optocoupler. Good luck..

@robertjacobs2338

Жыл бұрын

@@CircuitSecrets i figured nano would be nice because I already have one, but I decided to just by a pico for the better menu and whatnot. Thanks for doing this work and making this possible this is a really cool project. Do you think it would be possible to use the vfo to move outside of cb band onto ham? I do have a ham license

@CircuitSecrets

Жыл бұрын

@@robertjacobs2338 Thank you! Yes absolutely it can be modified to gain access to ham bands. You will need to modify the code a bit for that and there should be modifications to change the step sizes as well as a few tweaks for side band offset. I am planning a few of those mods for future releases.

Please stop propagating the mistake of calling virtually any micro controller based signal gen/VFO "DDS". This isnt DDS. Thank you

@CircuitSecrets

2 ай бұрын

DDS in this context stands for Direct Digital Synthesis. The SI5351 is a digital clock generator it directly synthesizes a signal based on a digital input signal which comes from the Arduino. So with all of those considerations, this design is simply a Direct Digital Synthesis VFO

@bazzaar1869

2 ай бұрын

@@CircuitSecrets No, DDS is specifically a technique where a stored sample of a sine wave is clocked out of memory at varying rates to produce "directly" a sine wave at the desired frequency. Skyworks do not refer to their Si5351 as DDS, because it isnt. The Analogue Devices AD9850 IS a DDS synth and VFOs based on it can be called DDS. Do some research, dont repeat KZread misinfo. Thank you.

@CircuitSecrets

2 ай бұрын

@@bazzaar1869 I just looked up the definition and utilization of DDS and you are correct. This is not DDS it could be said to be a PLL VFO but not a DDS, so thank you, I stand corrected.