07/19/2018 at 18:24 •
After I tried to fit all the components like Bandpass filters and Power Amplifiers on the mainboard PCB and i find out that they dont fit as whole on a 10x10cm PCB (this size is obtainable very cheap in China), i decided to put the filters and PA on a seperate PCB, which is connected to the Mainboard via a coax cable (for the HF signals) and a ribbon cable for the digital signals and power supply...
A benefit of putting the PA on a seperate PCB is, that the high power HF signals are kept away from the sensitive HF mixers on the Mainboard, which should help to minimize intermodulation products...
I've put the schematics for all PCBs on in the files section.
06/29/2018 at 12:46 •
The schematics of the Audio Board (here i even have a PCB) and the Mainboard are finished:
You can find them in the downloads.
On the mainboard are the (HF-) Filters and mixers, furthermore the main MCU, which also creates the sin/cos clocks. The board has connectors for Power and Antenna.
On the Audio board are the most of the amplifiers, RX/TX switches and the (audio) low-pass filter. Here do you connect the microfone and the speaker.
Now i will design a PCB for the mainboard, and a PCB for the microfone...
06/08/2018 at 17:33 •
The TRXW is based on the Weaver method (often also called third method) invented and patented by Donald K Weaver in 1956 (see here: https://patents.google.com/patent/US2928055).
For a good tutorial how this method works see this tutorial: https://forum.pjrc.com/attachment.php?attachmentid=9746&d=1487439697
The TRXW is based on a transceiver designed by B.Kainka in 1984, see http://www.b-kainka.de/SSBtrx.pdf for the german original version.