Who says homebrewing is dead? See these two recent reddit posts:
- A 21st Century Novice Station
- Radioberry – the pocket sized open source HF Trx based on the Raspberry Pi! Fantastic performance!
The 21st Century Novice Station is a home brew transmitter, keyer and tx-rx switch mated up to an SDRPlay receiver. When I asked about the T/R switch, the OP replied,
The schematics are all on my blog robs-blog.net, the tx rx switch is actually 2 relays, one cuts the tx line and the 2nd switches tx to rx. I have some LO leaking though and into the receiver, hence the 2nd relay. The setup is not all that practical.
To which another guy replied,
Cool setup! At the 5W level you can also use 1N4007 diodes as T/R switches (since they have a ‘sort-of’ PIN structure) to good effect. A little quieter than the relays.
I found an example of T/R switch circuit using 1N4007 diodes on the Ham Electronic Homebrewer blog.
Radioberry
The Radioberry is a Raspberry Pi hat that can be plugged into a Raspberry pi, forming a Software Defined Radio (SDR). It has the following features:
- Based on the open source Hermes SDR Architecture
- Can run multiple receiver slices (based on firmware)
- ~20 mW output
- Supports remote sdr operation via emulator mode
- Cost effective ( ~100usd )
The project wiki has a few more details:
- The Radioberry uses an Analog Devices AD9866 which is a 12-bit broadband modem mixed signal front end that has been repurposed as a direct down conversion (DDC) and direct up conversion (DUC) SDR transceiver covering 0-30 MHz
- The Radioberry uses an Intell Cyclone 10LP FPGA, supporting the 10CL16 and 10CL25. The firmware will be loaded via the raspberry pi.
- Power supply for the radio card is provided by the raspberry pi.
According to the designer, the project will be in continual beta status. All documentation can be found on github.
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