ILER 20 MK2
ILER 20 MK2 / 3-4W QRP SSB Monoband Transceiver KIT
Like I wrote in the introduction, for building my first QRP SSB transciever I choose to start off a little bit easy with the ILER 20 QRP transceiver from Javier Solans - EA3GCY. The old version of the kitt (ILER 20) has very good reviews and there are a lot of photo's on the net showing the variouse personal designed end products of them.
So to add more to that pool of photo's and pages I descided to write these pages about my MK2 version. Happy reading.
Javier made good work packaging all the the variouse components in different bags. The numbers don't really follow the building order described in the construction manual, but that no problem. I would recommend reading the manual at-least once to get the general idea about the assembly order (trust me, Javier knows best).
Tip : just open the bags for the components you need that step and use the component checklist to check off the installed components.
Tip : take you're time. There is no need to hurry. And installing 65 resistors, 83 capacitors, 3 adjust resistors, 2 trimmer capacitor, 1 potenciometer (volume), 8IC's, 14 transistors, 9 diodes, 12 inductors, 6 RF transformers, 1 variable capacitor tuning, 7 crystals. takes a little more time then soldering a flip-flop together.
The first batch of resistors are in place and so are the 100nF capacitors.
Adding the rest of the capacitors, the elec. capacitors, a few chockes and it starting to get some body.
Installing the IC sockets and the headers
Tip : for the IC socket I would recommend using the more expansive models. It would have saved me 4 hours debugging the combination of the first mixer and the microphone amp to find out that the socket was malefunctioning (both stand alone work fine).
Tip : installing the header by using a jumper for holding them in place will prevent burning you're fingers.
Then it all came fast together. Winding the toriod's is easy to do when you follow the instructions of the manual.
Tip : Winding the big toriod for the VXO takes some time and I would suggest marking every 5e turn with a CD marker so it's easier to count the windings.
Info : I lost a few photo's during some stupid camera action (delete yes/no can be tricky) so all I have left are the Instagram photo's. So the layout will be a bit messy.
After hooking up a spare speaker, my diy QRP dummyload / power meter and my current limited power supply (no need for burning copper when I screwed up something), it was the moment it all comes to the allignment of the variouse building blocks of the transceiver and when following the detailed manual it doesn't take that long.
All steps where taken with ease and after hooking up the enfed antenna some QSO's could be followed loud and clear (even with the bad conditions at that time).
Then it was time to hookup the DDS (lifting L7 from the PCB allows use of the DDS) and the microphone. Connecting a oscilloscoop parrallel to the dummyload it was possible to see the output waves. Hmmm and that looked funny.
Speaking into a microphone for testing the amplifier isn't the correct way. A manhatten style 800 hz 20mV generator gives a good baseline for testing and by using a dual trace scoop a good way to test the amplification of the amplifier.
Testing the building blocks separatorly they where all OK. But for some reason the first mixer and the microphone amplifier didn't like each other and started oscilating.
The source took me more then 4 hours to find. Or maybe better, replacing the IC socket of the LM741 for a more expensive one (re-inserting the 741 bend one of the contacts) and replacing the LM741 for a UA748 the problem was gone. So if you have that problem, change the socket and the LM741 for a UA748. It worked for me :-)
After the alignment it was time for the really big test. Trying to make the first QSO. And as expected with bad conditions in the air, it took some time. But that QSO came with SP8CUR 57/59 with just 3W output. Audio was ok. A QSO with OH5C/P confirmed it wasn't a lucky shot and a long QSO with local ham Eric PD3EDA made it for sure. It all works. Also tested posibility to switch between DDS and VXO. Check. Works. Happy ham :-)
On the next phase : boxing it all up.
Having some cabinets laying on stock, I used a little bigger one so I could use the VXO and the DDS. The DDS draws around 150mA current even with the display off and out in the fields. every mA counts.
The cabinet is exactly 120mm deep which doesn't leave much room for mechanical issues like the potentiometer and the PA transistor. 4 strips of PCB material gives 3 mm extra space giving enough space to put no mechanical pressure on any thing.
Controls / sockets / display from left to right top to bottom : DDS display, DDS dail, VXO dail, TX/RX led, AF gain, microphone socket, DDS/VXO select switch, tune switch (still needs PTT but will fix that when I'm at the local electronics store), power switch and headphone (mono) socket.
Front and back in place. Backplate has a BNC connector, a ATT switch, a fuse holder on the inside and a DC socket.
Testing a MASSOTH 8241020 speaker (the same I used as a upgrade speaker in my FT817) on a toillet role to get more base.
For startes I used a bunch of knobs which I had in stock, but for the moment they seem to work out well (a bigger knob for the VXO is a absolute must when you don't have a geared knob). A hand drawn speaker pattern was drilled in the top cabinet plate and a brase strip holds the speaker in place (a small piece of dual sided sticky tape prevents slipping),
Everyting put together and in the days after the final assembly a few new QSO's where added to the list. Can't wait to take the ILER outside and use it for field days :-)
All the Instagram photo's from this project in chronological order :