RS-HFIQ Technical Information Site

The RS-HFIQ is available now from HobbyPCB.com and can be ordered here.

The RS-HFIQ is an open-source project designed to translate I and Q baseband signals to RF in the 80/60/40/30/20/17/15/12/10M Amateur Radio bands. The I and Q signals must be provided/processed by external signal processing which could be a PC running Software Defined Radio software, a stand-alone digital signal processor and some form of analog processing.

The project was launched as a KickStarter campaign. Even though the campaign is over there's lots of good info, descriptions and our video.

The receiver in the RS-HFIQ consists of 5 band-pass filters to reject out-of-band signals, a LNA with frequency dependent gain and a conventional quadrature down-converter.

The transmitter in the RS-HFIQ uses a Quatrature up-converter followed by the same band-pass filters used by the receivers, a 5W power chain and a low-pass filter bank.

The Local Oscillator is based on a Silicon Labs SI5351 chip that can produce up to 3 RF outputs, the LO signal for the up/down-converter, a built-in test signal for calibrating I and Q offsets and an external signal.

The control of the SI5351 and all switching functions is provided by an Arduino Nano running open-source software and programmed with the Arduino IDE.

Special care has been taken to insure noise and ground-loop set-up. The RS-HFIQ has three separate DC isolated ground planes; RF/Chassis ground, Baseband/Audio ground and Digital ground. This allows the same PC to be connected to the audio in/out and the USB port on the Arduino Nano without creating noise/grounding issues.

Here is a block diagram of the RS-HFIQ transceiver (click on it to see a larger version):

The transceiver board is 100X160mm and slides into an aluminum extrusion or can be mounted using 4 mounting holes.

This is a photo of the Rev B prototype board: (Click on the image to see a larger version)