So i got busy today and wired up the uBitx. Turned it on and tuned around a little to find some signals, well there was not much going on anywhere but I did manage to find this one ZL on an other wise dead band. Its good to know that the receiver works, now i just have to wire up a mic and check its working on transmit. But that is going to be another day.
So I recorded a little video from tonight’s 7.130 dx net. I have been giving the receiver a good workout to see how I like it. So far, to be honest, I think i prefer the Bitx40 over the uBitx. Though, it might be I just need to play with the IF and BFO settings to move the bandpass around a little to where I think it sounds better.
Started to put the uBitx into a case. I did the front panel up on a mini cnc and it certainly has turned out better than anything i have hand cut in the past. Used 1mm aluminium plate with is nice and easy to work with and the filing to clean it up at the end did not take long at all. Its not perfect, there are a few things that could have been aligned better, but it is what it is and that’s how its going to stay LOL.
Something i was not happy with was how the heatsinks were mounted flush to the board. If you use this radio portable eventually they will rub through the soldermask and short out on traces. So i grabbed a couple of other heatsinks i had laying about here, drilled and tapped for some isolation between heatsink and board. I also using insulating hardware as well because the fets tab is live and things go bad when you short things to ground that are not meant to be LOL.
Board is now mounted and just awaiting wiring up.
Front panel now with knobs on. Just have to wire it up and be done. Oh and yeah I use a speaker not headphones so I can use 1 less jack and I also use a 4 pin mic socket rather than jacks.
So, it been a rather big week at work and I did not want to start something that will take me weeks to build and I thought I would get this done today in an hour or so and be testing it. Well one thing lead to another and I still need to make the low pass filter for it. Well that looks like a job for tomorrow. Nothing extraordinary here, 100mhz oscillator and ADE-1 mixer and a 5v power rail for the oscillator.
Putting the finishing touches to the antenna tuner project, I just need to cut the shafts down a little and put the knobs on. I have given it a test into 2 dummy loads, a dummy load and my 40m antenna LOL, and the led comes on super bright with 5w going in. All in all I am pleased with the outcome, though i would have preferred it in a smaller case, but the inductors use kind of determined the case it when in.
So with the new year comes new projects, I am not going to set out what my overall plans and goals are as I have started way to many things and never bothered to see them through or to complete them. So with that in mind, I am building a L match
Its hard to make out, but you can just see the LED glowing, the signal is 10v p-p from the signal generator, the load is a decade resistance box. At infinite swr there is 1/2 the p-p voltage at the junction of the rectifier and capacitor. As swr approaches 1:1 the voltage drops to a point where the LED turns off. Its simple and its a winner.
It will get paired up with the sotabeams switched inductor and a 8-370pf air capacitor. as an L match. Should be good enough for the kinds of girls i go out with. Below is the schematic I am following for this project and a link to the authors site is at the bottom of the page. In the final build I will use 3w 50ohm resistors and the diode i used was a Schottky, i don’t recall the numbers it was just something i had in the parts box, I used the Schottky for its lower voltage drop, though that is probably not all that critical seeing that LED’s are current limited, not voltage.
This is an interesting little kit and not much information on the net about its use so I thought that I would add a quick blog entry about what I discovered about it. I am building an L match and started with the inductor. I really had no idea on windings, so i started with 6 turns and added 2 turns per inductor, with the 7th inductor having 18 turns on it. I spent about 20mins working out the switch, it is meant to be a 6 position switch, which in reality is a 10 position switch with a limiter. However in my case, it looks like i was given a 5 position 2 pole switch. While mildly annoying, with 5 positions I get 270nH -> 3.7uH inductance, and if i switch from the low side input to the high side input gives 1.7 -> 5.5uH, while adding switching is a pain in the arse, it is not the end of the world to have one inductor not in the loop. If i had realised before soldering in the switch i would have used a 10 position switch i have here and made it work right from the beginning. It is what it is, no use worrying about it now. 3.7uh is more than enough inductance for any antenna i build.
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.
With the arrival of some solar panels and an ADC in the post today, its back to the weather station to getting it fully working by January. I have worked out where its going to live, now i just have to put the door on the front, some bug screen over the vents and paint it white so that it stays as cool as possible in the harsh unforgiving Australian Summer.
The panels apparently put out 1amp each at 5v. Yeah right, but 1 is putting out enough current to turn on the charge circuit and so thats a win. 2 Panels should in theory keep the batteries fully charged in the daytime and run everything, just fine. 2 might even be overkill, but I do not want to run out of battery because its been cold and overcast for 5 days. But hey I think my math is ok and it should survive 5 days without sun.
Well i have it all built, now i need to dig out a DDS LO and give her some power and see if it is a skookum choocher or if the pixies turn to smoke and leave the building just like Elvis. I did not enjoy building this all that much, the form factor is tiny and everything is stuffed in there as tight as it can be. But, if all goes well, tonight we might hear something coming out of a speaker.