vrijdag 26 april 2013

Bitx20 V3 "Dead Bug Style" Post IF-Amplifier and 1th Mixer section

After a few hours of soldering ,I almost completed the 7th and 8th stage of my Bitx20 V3 "dead bug" style 20 meters QRP Transceiver project.Transformers T1 and T1a are the same as in the BFO.13 trifilaire windings thrue the ferrite core.For the diode bridge I used a piece of double side PCB.Just one more transformer has to be wound,but I will do that the next time.After that I have to test the whole circuit.

donderdag 18 april 2013

Bitx20 V3 "Dead Bug Style" 2nd IF Amplifier + Crystal filter.

Just completed the 2nd IF stage amplifier and the 10MHz crystal filter.The "beeps"on 10MHz are now hearable with a piece of wire as antenna and I had to turn the volume as low as can be,what a gain.When I touched the 10MHz IF crystal with my finger,I could hear a foreign radiostation.Yes,the first signals are received.

On the picture bellow,the six stages of the Bitx20 V3 are shown.Next stage is the build of the post IF-amplifier and the first mixer section.

Bitx 20 V3 "Dead Bug Style" BFO section.

I build the Bitx20 V3 Audio Section in about 3 hours.So it was time for the next chapter,the BFO/Modulation section.I took another 5 by 5cm double sided board.On the picture bellow you see the transformer made of a binocular core.Put 13 trifilaire windings thru the core and beep the wires for right connection.Stick it to the PCB with a hot glue gun.In this stage ,I put it together with the audio section.Apply 12Vdc to the receive line and now you can receive the "beeps" on 10MHz when you use a 10MHz crystal as IF.This is also the part where you can determine if your crystals for the filter match.I used a IC-connector,so I can easily change the crystals in and out the socket for measuring the right frequency.So you can pair the crystals for the crystal filter.Just connect your frequency counter and search for 5 chrystals where the frequency`s are closed together.

Bitx20 V3 "Dead Bug Style" Audio section.

While I was still waiting for my Multiband Bitx printed circuit boards and all the parts,I wanted to build another Bitx20 V3,just too kill time.So I took a large piece of double sided copper PCB and made a few little boards ,just 5 by 5cm.The plan is to build one or two sections of this popular homebrew QRP transceiver on this 5 by 5 board.Then place it all togheter on a larger board to make it a complete and working 20meter QRP transceiver.On the picture bellow you see the audio section with the LM386 for the speaker and the two 2N3904 transistors.When you apply 12Vdc to the receive line,you can hear some noise comming out of the speaker while turning the volume up.When you also put a + on the transmit line,you hear a very loud tone coming out of the speaker.So now I know the circuit is working.

Multiband Bitx (2)

This week all the remaining parts of my Multiband Bitx project were delivered at my door.Tuesday I got my PCB`s from Sunil Lakhani.Wednesday the ADE-1 mixers from Boris LZ2JR arrived.(Thank you so much Boris!),and today the Linear Board from DXkits.com arrived as well.
On the picture you see the complete PCB kit from Sunil Lakhani VU3SUA.On the right corner you see the Linear PCB from DXkits.com.

ADE-1 mixers from Boris (LZ2JR) as a gift.

donderdag 11 april 2013

Multiband Bitx (1)

After the succsesfull build of three Bitx20 20 meter QRP transceivers,it was time for another project.My first idea was building the Lima SDR,but I`m an old fashion guy,and as the computer is a very important component of the SDR kit,my choice fell on the Multiband Bitx.
Today all of my parts I ordered are arrived.Only the ADE-1 mixer is missing on the picture.LZ2JR was so kind to send me two of those missing parts.Hopefully Mr.postman delivere`s them this week.Another very important part of the build are the PCB`s from Sunil.I`m still waiting for the exciter,LPF,BPF-pcb`s.Last week I made a reservation for the linear PCB on the dxkits.com site.

On the picture you see the complete bandpass filter set by G4CFY (Spectrum Communications) and the rest of the parts for making the exciter and the complete bandpass filter from 10M to 160M.