Marconi Canada receiver type XH100

The only reason I paid (a little -- I think R100 for both) money for these is that they are almost completely unknown on the internet, and I was curious.

The PCB accommodates four channels, but these units are built for one channel only. There is space for four input filters, four fundamental and four overtone crystals, and separate coils to resonate the overtone crystals.

It seems a conventional design, with the switchable front ends, an SBL-1 diode ring mixer, and a crystal oscillator as mentioned. There are two crystal filters, one for AM and USB (does this mean that in AM mode only one sideband is received?) and one for LSB, followed by an MC1350 amplifier and MC1496 detector. Because of the two crystal filters, only one BFO crystal is used, at 10.7000 MHz. AM happens via a CA3088. Audio to the front speaker is via a TDA2002, and there's also an LM380 which I assume drives a remote speaker.

The date codes date these radios to late 1979.

The crystals live in a neat little oven, which is probably why VO1NA and G3NYK used an XH100 to provide a reference signal.

While the plate clearly says "115V" the transformer has two primary windings and these are wired in series for 220V operation.

Coverage is 400-500kHz and 1.8-24MHz. Modes are USB, LSB, AM and RMTE -- possibly "remote"?

Serial 158's crystal is marked 12.749MHz and 2.0490 while 169's crystal is marked 12.882MHz and 2.1820. The latter (2182kHz) is a maritime weather report frequency for what it's worth.