South Midlands Communications SMC-73 RX

[Geoff G4ICD]

[QUOTE=David G4EBT;1489253]

Originally Posted by Jon_G4MDC

I'm glad it wasn't just me!

Maybe the SMC-73 used bipolars with a redesigned coil assy in that case.
It's why I would love to see the schematics.

The blurb in the advert states:

"FET's are employed in the R.F. Amplifier, mixer, VFO and BFO (these latter two stages being fed from independent stabilised supplies) ensuring good sensitivity, stability (electrical and mechanical) dynamic range (helped by adjustable RF attenuator), and marked freedom from "pulling" of both the local and beat frequency oscillators".

Cosmetically it's so similar to the 9R59 that it certainly looks like it has Trio's fingerprints all over it, but branded 'SMC'.

SMC were quite an outfit in the 70s. They still exist but have abandoned amateur radio (I don't know when) and reverted back to what they did at the outset - antenna masts and professional communications. Not been located in the South Midlands for many years. Whether they still have any staff or records relating to their amateur radio years who could perhaps throw any light on the 'SMC 73' radio I very much doubt after 44 years, but it might be worth a try:

https://www.devex.com/organizations/...ions-ltd-38487

Link is well out of date, I retired 8 years ago, there is no amateur radio information available as it was all scanned and then sold/removed in 2002 so no point in wasting time asking anybody at SMC or people emaiing me for help as the link gives my name. Geoff Brown G4ICD

[Jon_G4MDC]

That's very interesting Geoff.

I well recall the Chandlers Ford address but not an Axminster one. I visit Axminster now and again - a very nice place.

I don't suppose you have any info about this old RX?

We would love to know details about a solid state version of the 9R59.

<Later edit> I was out of sync here. Mods please delete if appropriate. My sentiments remain - looking for a schematic if anyone can oblige please.

[John KC0G]

This thread ran in parallel with another with the same subject at the RSGBWorkshop group at groups.io

There, Martin, G8JNJ, noted that the SMC-R73 was the same as the Minix MR-73B. See https://www.rigpix.com/minix/minix_mr73b.htm

Ian, M5IJH, found a translated copy of the German manual for the Minix MR-73B. I have attached it. It should be enough to keep most of us happy.

It was also noted that the MR-73B looked like a forerunner of the DX200/qp666 and clones.

HTH and 73

John KC0G / M0KCY

[Jon_G4MDC]

That's excellent John - thank you very much. A nice touch it includes a 3.5MHz marker to find the edges of the ham bands.

So ordinary JFETs 2SK19 in RF MIX and LO...