  The DRAO Synthesis Telescope (ST) is a forefront telescope for imaging
large-scale neutral hydrogen and polarized radio continuum emission at
arcminute resolution. Equipped for observations at 1420 and 408 MHz, the ST
completed the Canadian Galactic Plane Survey, providing pioneering measurements
of arcminute-scale structure in HI emission and self-absorption and of the
diffuse polarized emission, using a fine grid of Rotation Measures to chart the
large-scale Galactic magnetic field, and advancing the knowledge of the
Galactic rotation curve. In this paper we describe a plan for renewal of the
Synthesis Telescope that will create a forefront scientific instrument, a
testbed for new radio astronomy technologies, and a training ground for the
next generation of Canadian radio astronomers and radio telescope engineers.
The renewed telescope will operate across the entire range 400 to 1800 MHz.
Collaborations between DRAO and university partners have already demonstrated a
novel feed antenna to cover this range, low-noise amplifiers, and a new
GPU-based correlator of bandwidth 400 MHz. The renewed ST will provide
excellent sensitivity to extended HI, covering the Galactic disk and halo,
spectro-polarimetry with unprecedented resolution in angle and in Faraday
depth, the ability to search for OH masers in all four 18-cm lines
simultaneously, and sensitive recombination-line observations stacked over as
many as forty transitions. As a testbed the renewed ST will evaluate low-cost
digital clocking and sampling techniques of wide significance for the ngVLA,
SKA, and other future telescopes, and a prototype of the digital correlator
developed at DRAO for SKA-mid.
