Ok, back to doing some work on the Bebek. In this block the only real issues are that there is an extra DC blocking cap on the board that is now shown on the schematic and that the Cap values on the schematic are not the same shown on the board. In this case I have defaulted to using the values on the board. 10nf and 100nf on the board are 1nf and 10nf on the schematic. The former values just seem more logical to use and the latter are most obviously an error on the part of the designer.
So the LO Buffer Amp has a 10x gain. I injected it with a 250mV signal to get 2.5V out. Now obviously this is not good if you are using a SI5351A as it puts out 1.5V. But this should work quite well with an AD9850 which puts out 200mV. It still might be a little to much drive for a -7dB mixer, but it should be ball park upper limit.
It seems like now days every man and his dog has a DDS/Digital Synth VFO project happening. I have had a couple and I am pretty sure that there are even Gerbers floating about on my blog for that very thing and was one of the very first boards I ever designed and laid out.
Well, times are a changing and rather than just a simple VFO, I have designed a board to control all aspects of radio control. To fit all the functions into one microcontroller required a bit of a step up and the use of an ATMega because I needed that many digital pins.
So what does it do? Well: 1. Real time clock and keyboard for logging contacts, digital modes like RTTY and keyboard CW.
2. Rotary encoder for the SI5351a VFO obviously.
3. 8 push buttons for various functions like band changing, mode changing and setting the attenuation level. On my front end board i have a 32 step rf attenuator in 0.5db steps, and for selecting 1 of 2 audio filters, but this might change yet and become DSP audio filtering with a lot more options at a latter stage.
4. Setting relays both bandpass and lowpass filters for 4 bands and selecting one of 2 IF Filters.
Now i am only releasing the board files, the software is something you are going to have to write yourself, because my code is not complete and probably wont be complete for sometime. I have most of the basic functionality written, but it all needs fleshing out and cleaning up. Now its nice when someone does it all for you, but, this will be pretty slick when complete and well, i dont want anyone making a commercial product out of my work and so the code will probably never be released. But these board files will save you hours of work, even if you have to code it all yourself.
Radio Bebek by the Bogor Homebrew Radio Community in Indonesia. Its an interesting little qrp radio that uses very common off the shell parts, mostly. There are a couple of oddities and absolutely no build instructions at all. So its not a build for the faint of heart, its a lot of reading the schematic and buzzing out the board to know what goes where because there are NO Part Designations on the board, only values and in some cases those values are wrong. But, i am having a go at building it and seeing how i get on with no instructions and only a schematic. Wish me luck. I do not think i will make this a transceiver, but will build it as a receiver only as i want to match this up to a 10w CW transmitter i have built.
The project can be found here on the authors website. http://blekokqrp.blogspot.com/2018/08/radio-bebek-40m-lsbusbdigital-qrp.html
Saturday morning, not usually a day for mail here, but because its christmas the parcel guys are working weekends to make sure they keep up with the volume of mail at this time of year. It also means I have the new uBitx sitting in my hands.
So Ashar Farhan the legend has brought out a new Bitx radio, the uBitx, its 10w multi band rig, with CW and SSB. I have one on order and should see it I hope before Christmas. Its going to be my permanent portable radio. I am going to sell off the FT897 and just use this for portable. Kind of excited.
Well its the pigeon pair. I got the matching tuner to go with the HB-1B. The plan is to use it with a SotaBeams 10m pole and vertical wire and a couple of radials with the HB-1B and the Bitx 40 in some of the more space limited places I wish to operate from. I have everything here to acheive this, its just a matter of going down the local park with the laptop and antenna analyser and the rigs and getting things all sorted out.
So i have finished putting the Bitx into a box, adding in a Si5351a for the local oscillator and making the radio very frequency stable. I did have trouble with digital noise leaking into the audio amp, but I got those issues sorted out mostly, with only the rotary encoder giving chirps into the audio. I think with some more decoupling and use of shielded cables throughout even that would be taken care of. Whats there I can live with. I have made some contacts with the radio and worked my first DX with it in New Caledonia. Even with a nice report.
The radio being used on air to make contacts with Steve VK3MEG.
The receiver in action
The transmitter as being received by VK3MEG 1500km away.