QSK CW QRP Transceiver 2W TY40a OM3TY
Two months before the summer race The original QRP04 I thought about it, with which devices will I broadcast. So far, I had a DOB80 at 80m, Norcal20 a NAXOS20 na 20m. I also own an FT-7, however, I enjoy broadcasting more on devices, which I will build myself. I use FT-7 more or less on 80m SSB.
Some time ago, I discovered interesting connections of qrp transceivers Minowa Makotu 7N3WVM on the Internet. He used interesting ICs in his connections, FM receiver TA7358 in SIP9 case. They have a separate input amplifier and work with voltages ranging from 1.6V to 6V. Their price also stands out. They are five times cheaper, if NE602. This inspired me to build a small trx with a power of up to 2W.
Wiring diagram
Sound No.2, 175kB MP3
Used parts.
Components are not critical. I myself used mostly soldered components from various discarded devices. Mainly capacitors, resistors.and transistors.
In place of coils L2, L3, L4, L5, L9 and L10 I used unknown soldered coils in sheet metal solderable covers size 7.5mm. The coils are tuned by a hollow core. That is one solution.
The second solution consists in replacing MF transformer lenses with Toroidal Cores + Cx. I want to point this out, that the alternative values of the number of turns of the toroidal coils are informative. Everyone has to fine-tune themselves.
| L2 – 5uH | 2z / 35z material | T37-2 | 0,25mm |
| 2z / 23z | N05-6,3 | 0,25mm | |
| 2z/32z | NO2-6.3 | 0,25mm | |
| L3, L4, L9, L10 – 5uH | 35With | T37-2 | 0,3mm |
| 23With | N05-6,3 | 0,3mm | |
| 32With | NO2-6.3 | 0,25mm | |
| L5 – 15uH | 61With | T37-2 | 0,20mm |
| 57With | T44-2 | 0,20mm | |
| 42With | N05-6,3 | 0,25mm | |
| 31With | N05-10 | 0,30mm | |
| L13,14 – 1,2uH | 11With | N05-6,3 | 0,30mm |
| 7With | N05-10 | 0,30mm | |
| TR1, L11 | H6-6,3 | 0,40mm |
Cx1,2,3,4,5,6 50pF
C5,7,11,12,39,41 82pF
In position L1, L6, L7, L8, L12 I used standard axially encapsulated chokes.
Q1 can be replaced by KC type transistors, BC.. etc..
Q6 can be replaced by type KSY34, 2N2219, 2N3866, 2N4427 apod.
It is appropriate to use Russian military 50 ohm headphones, which are also like an nf filter, because they operate in the band around 4000Hz. I tried ten different headphones and it was the Russian military that performed best in my tests.
The entire tranceiver is built on universal printed circuit boards, placed in a hand-made box made of aluminum sheet and cuprextite.
Testing
I set up the transceiver on a professional spectrum analyzer.
I measured Rx sensitivity with MF filter 400Hz 0.25uV and harmonic suppression PA / 2W around 52dB.
Current consumption from the source at RX = 26mA and TX / 2W about 240mA.
The government of OK1SVB promised the design of printed circuit boards. Let's hope so, that in the shortest possible time?.
Alex, OM3TY, 72.
