Slowly integrating all these bits together in software and currently all the relays are clicking in sequence when I change bands on the control board. If you look closely on the upper right, you will see an updated version of the Band Pass Filter board that uses different inductors and filter topology. I need to populate and test one filter to ensure its right and then build the entire board.
Something that I did not notice was that when I changed Ecad software my mounting hole pattern has changed slightly, so neither of the old filter board designs will stack with the other boards. So i have to redo the low pass filter board and I am going to redo the rf frond end board as well and move things around to make it a little more usable and to make sure the 3.3v regulator has a heatsink on it. With bugger all current running though it, it still gets burn your finger hot and that is not right. I am starting to wonder if these ebay parts are actually dodgy or something.
So I am sitting here this morning drinking a massive cup of espresso coffee and thought i really should post up where I am at with the receiver project. Its getting closer now to final testing and making noise. In fact, the final board will arrive today from china and as long as it does what its meant to, i might only be days away from hearing beeps
So anyway, onto the IF amps and mixers. I find the whole amp design, input and output impedance matching and how one can effect the other to be slightly confusing. So I went with an IF amp design that eliminated that confusion for me, the TIA amps. Termination Insensitive Amplifier by Wes Hayward
The mixers will be ADE-1 Mini Circuits jobs as I have a bunch of them here doing nothing and figured why not. I do have a board here I am designing with a number of different mixer topologies on it that I will eventually have made and test out homebrew mixer designs more fully, but for now I will use the commercial product.
I built the 2nd IF amp first, so I can have a direct conversion receiver happening in short order once I have a working audio board.
Well it works as designed and does the business obviously. There is a missing trace on the board, so I will eventually have to respin them and I want to fix the layout somewhat also and change the transistor footprints to wide not narrow. I do not like those small pads to solder to. LOL
Its new years ever and I have been thinking about the things I have achieved in 2018 and its been quite a lot, but at the same time, there has been a lot that I have not completed or even made a dent in and others that I have failed at.
So this list is the list of projects I plan to complete in 2019. Some of these I have had for sometime, some are not even in existence yet but are coming soon and some might be absolute dismal failures. Some of these can be competed in an afternoon and others are going to take some time, but here we go with the list.
1. Bebek Radio
First on the list is to finish the bebek, at least to receiver level. I do not think i am brave enough to tackle the transmit side of it. Its been an interesting and frustrating project so far, the sooner its over the better.
2. Pixie Transceiver
Ok, so i have build one or two of these before, but I have this one in the draw still and I should build it and attempt to make a contact with it, or at least get spotted on the Reverse Beacon Network calling CQ with it.
3. 49’r Transceiver
There is a similar kit on ebay called the Frog Sounds that I built ages ago. The receiver in it actually worked quite ok, but i never ever transmitted with it, let alone made a single contact with it.
So what I plan to do with this kit is modify it to use a DDS VFO and make it frequency agile. To achieve that i will add a bandpass filter to the front end and use a AD9850 DDS to inject a signal where the Xtal oscillator currently is.
I was given this maybe 2 years ago from a friend, Simon VK6MSC. Its been sitting in my draw waiting and waiting to see the light of day and get built. Now that I can actually use digital modes, I am itching to get this happening and on the air every other moment I am not using my radio and antenna.
5. Super Rockmite
Another ebay kit i have has sitting around for a long time. I am not sure weather to build as standard to modify it to make it frequency agile. At this stage it might just be an afternoon build and see if I can make a contact with it. The built in keyer is a nice touch.
Now we are getting into serious build territory. The QCX is more than a toy kit, it is a quality transceiver kit that I will take my time building and will enjoy using.
7. VK4FFAB 4 Band Receiver
This has been an eternal project that has no end in site. I would like to have completed the board above built and connected together to see how it actually works as a receiver. Each of the boards has been built and modified in isolation and what is pictured above are 2nd and 3rd iterations of some boards. Along with just stuffing the boards there is a whole lot of software to write to control the whole thing. While its mostly done, there is still a lot of work to go.
8. QRP Labs QSX
Not a lot i can write about this, other than I will be dropping everything and building one once the kit is fully released. All i have at the moment is the 10w PA. This kit i am excited to get my hands on.
9. ZOI-40 Tranceiver
This is one of those projects that I may or may not get to. Its another board laid out by YD1JJJ from Indonesia. I have not taken a close look at things, but i kind of expect this to be a nightmare like the Bebek and something that I will have to buzz out and compare between board and schematic to complete.
10. Bitx 20
Where the BITX craze kind of went viral, the Bitx 20m will be something I tackle when i get time.
11. Other Notable Thoughts and Ideas
There are really only 3 other ideas floating around at the moment and that i would like to get to this year and they are all transmitters. A CW transmitter, a RTTY transmitter and a PSK transmitter. 3 individual or potentially combine into a single unit to pair with my receiver project. These will take precedence over some of the projects above and will make nice additions the the lineups.
To be honest, I have certainly listed out more stuff than I will probably get to, but these are the things I have in the pipeline and are my immediate list of goals. The hardest part with all this is not getting sidetracked and going off on a tangent.