AD5GH

Welcome!

This is a site for those interested in building their own HF amateur radio station equipment.

The site documents my current station consisting of the 2020 HF Transceiver and MRF101 amplifier. Detailed information is also included for the Express Receiver and some limited information for a 6146B amplifier; in addition, I am starting to document the 2022 SDR Transceiver.

I don’t own a commercial rig and operate exclusively digital modes, mainly FT8. I find FT8 to be a fascinating mode in terms of exploring propagation, antenna performance, and receiver performance. As of November 2022, I have completed 5-band DXCC (40, 30, 20, 17, & 15m) with a 43-Ft vertical and 80m (135-ft) EFHW for 40m.

The Express Receiver was designed and built between 2014 and 2016, as such, some of the parts I used may no longer be available, however, for most there will be substitutes.

December 10, 2022 Update. I built a second version of the 2020 HF Transceiver in early 2022 in which the Rx and Tx audio shaping circuitry was replaced with a Sotabeams Digital CW and SSB Band Pass Filter Module, and GPS correction of the two Si5351s was implemented. Incorporation of the Sotabeams filter module necessitated a redesign of the following boards:

• SSB Generation, SSB Detection, and Audio Board
• 9-MHZ IF and Digital AGC Board

Version 2 details will be added to the 2020 Transceiver page. Version 2 has been my main station transceiver since May 2022 with the original transceiver still fully functional as a back up. I highly recommend the Sotabeams Digital CW and SSB Band Pass Filter Module for audio filtering in a homebrew analog receiver or transceiver.

In October 2022 I started building the 2022 SDR Transceiver. The DSP aspects of the transceiver are based on work of Albert F. Peter, AC8GY, and Dr. Jack Purdum, W8TEE. Two new boards were developed to adapt the existing transceiver design to SDR:

• Teensy 4.1, Transmit and Receive Audio Board
• QSD, QSE, LO, & GPS Board

These two boards replace the following boards in the analog transceiver:

• SSB Generation, SSB Detection, and Audio Board
• 9-MHz IF Amplifier & Digital AGC Board
• 1st Mixer, Roofing Filter, 2nd Mixer, Post Mixer Amplifier, and LO and VFO Board

Although not yet on the air, Rx and Tx are chains are working on 9 bands. Remaining work includes bringing in additional DSP functionality from Jack and Al’s code such as AGC, and designing a new power amplifier as the TAPR Pennywhistle amplifier used in the 2020 Transceiver is no longer available.

November 15, 2021 Update. The 2020 HF Transceiver was used on the air for the first time on October 30, 2021, and has since been used on all bands. From start to finish, the build took approximately 15 months.

The 2020 Transceiver started out in 2020 as a concept with the following objectives in mind:

• Build a highly integrated transceiver
• Learn KiCad to take advantage of low cost PCB manufacturers in Asia
• Maintain the building block approach of the Express Receiver / Transmitter
• Utilize H-Mode Mixers and a Quadrature Sampling Detector (QSD / Tayloe Detector)

The only objective not met was the use of H-Mode Mixers. I decided to use Analog Devices AD831 monolithic mixers in the 1st and 2nd mixers stages as I was very pleased with the performance of the Express Receiver and it was the fastest route to getting the transceiver on the the air. The modular nature of the transceiver will allow later upgrade to H-Mode Mixers by simply changing out the 1st Mixer, 2nd Mixer, Roofing Filter, & Post Mixer Amp Board.

Thanks for visiting.

Rod, AD5GH

Windham, New Hampshire

December 2022