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:

• 2022 SDR Transceiver – conversion of the 2020 Transceiver to DSP
• 2020 Transceiver – analog up-converting superheterodyne transceiver
• MRF101 150W Linear Amplifier
• 6146B 100W Linear Amplifier
• Express Receiver

I don’t own a commercial rig and operate exclusively digital modes, mainly FT4 and FT8. I find FT4 & FT8 to be fascinating modes in terms of exploring propagation, antenna performance, and transceiver performance. As of August 2023, I have completed 6-band DXCC (40, 30, 20, 17, 15, & 12M) with a 43-Ft vertical and 80m (135-ft) EFHW for 40m.

In October 2022 I started working on the 2022 SDR Transceiver which is a conversion of the 2020 Transceiver, a traditional analog transceiver, to an SDR based transceiver. The DSP aspects of the transceiver are based on work of Albert F. Peter, AC8GY, and Dr. Jack Purdum, W8TEE. One new board was eventually developed to adapt the 2020 Transceiver design to SDR:

• QSD, QSE, LO, Teensy 4.1, & Audio Board

This board replaces the following boards in the 2020 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

In early 2022 I built a second version of the 2020 Transceiver 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 have been added to the 2020 Transceiver page. I highly recommend the Sotabeams Digital CW and SSB Band Pass Filter Module for audio filtering in a homebrew analog receiver or transceiver.

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.

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.

Thanks for visiting.

Rod, AD5GH

Windham, New Hampshire

December 2022