South Midlands Communications SMC-73 RX

[JohnBG8JMB]

Can anyone provide any details of the South Midlands Communications SMC-73 RX? A manual or circuit, or pointer to one would be great!
73
John G8JMB

[vu2nan-nandu]

Hi OM John,

Here's some information.

https://worldradiohistory.com/UK/Sho...WM-1978-08.pdf

(see page 341).

73,

Nandu.

[Station X]

That bears a remarkable resemblance to the Trio 9R59DE.

[vu2nan-nandu]

Here's a direct link to that page, John.

https://worldradiohistory.com/hd2/ID...-08-IDX-15.pdf

73,

Nandu.

[Radio Wrangler]

Originally Posted by Station X

That bears a remarkable resemblance to the Trio 9R59DE.

It might be, all sorts of things turned up in different guises, but if so SMC were at risk of upsetting people back in Japan... Maybe this was from just before they became the exclusive UK importer for Yaesu Musen?

David

[JohnBG8JMB]

Thanks for the info; my guess is that it's solid-state pcbs in the 9R59 chassis.
Pehaps to use up leftover hardware? It's not my set - a friend asked if I knew anything about it.

73
JohnG8JMB

[Radio Wrangler]

SMC didn't come over as technically brilliant. Yaesu made a flagship transceiver and called it the FT-One. It was horrible! lots of features but the worst phase noise out of any amateur transceiver and ring-prone filters. It got a right slagging, and SMC fought hard defending it when everybody knew it was junk. Some people had fallen for the advertising and saw it as a prestige item, they got ragged a bit for buying one.

So the interlude just made SMC look bad if someone technically competent read their statements in defence.

Anyway, I doubt that this receiver has any more connection than their the name printed on it. I'd have saved up the extra £25 for the FRG-7 which was Yaesu's take on the RA17 architecture.

David

[vu2nan-nandu]

Originally Posted by JohnBG8JMB

Thanks for the info; my guess is that it's solid-state pcbs in the 9R59 chassis.
Pehaps to use up leftover hardware? It's not my set - a friend asked if I knew anything about it.

73
JohnG8JMB

My pleasure, John!

Yes, The front panel layout of the Trio 9R59DE is identical to that of the SMC-73.

73,

Nandu.

[Station X]

Originally Posted by JohnBG8JMB

Can anyone provide any details of the South Midlands Communications SMC-73 RX? A manual or circuit, or pointer to one would be great!
73
John G8JMB

I can't help with a circuit, but it would be interesting to see what's inside.

[Radio Wrangler]

It may well be a bit of a rarity.

David

[G6Tanuki]

It may look like a Trio 9R-59 but the description says it's all-solid-state...

[Radio Wrangler]

With the bandspread dial and the very low price, I'd expect a single superhet into a 455ish kHz IF.

David

[Jon_G4MDC]

Maybe from the period where it was fashionable to replace valves with FETs? No doubt with new circuit boards etc in this case.

I could never get that substitution to work. The FET stages were always unstable. Looking at the published efforts on the subject usually turns up Q slugging resistors across coils etc "to tame the beast".

Maybe this one was done properly? Wouldn't it be good if a schematic turns up.

[Radio Wrangler]

There were even FET-based plug in 'replacements' for valves. They allowed you to get straight to the stability issues without soldering in many RF cases.

There has always been a preference from some people for FETs over bipolar transistors 'because they are more like valves' Pat Hawker suffered a bit from this. But the reverse transfer characteristic is a lot larger than you get with the pentodes formerly used in RF and IF stages, hence the difficulties.

I remember a magazine article where someone had FETified (FETulated?) an entire HRO. There seemed little follow-up, and I suspect that people may have discovered that they'd converted a receiver renowned for good operation near big signals into one of the worst.

FETs have very large spreads on their parameters, and just to get even the bias conditions right lead you into device selection and SOT components. You have to work very hard to design around these problems.

David

[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.

[David G4EBT]

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

https://www.ebay.co.uk/str/southmidl...municationsltd

Although in 1978 it was advertised as a 'low cost' receiver, at £114 + VAT. Cheap perhaps relative to other receivers of the day, but certainly not by today's standards. In 1978 there were two VAT rates - 8% and 12.5%. (From 1979 - 1991 there was a single rate of 15%). I don't know which rate applied to short-wave radios, but assuming it was 8%, that would make the price £123. Accounting for inflation, that equates to £815 in 2022. Are Short Wave amateur general coverage radio receivers still marketed today? I've no idea, but if so, I think £815 would go a lot further!

Historical VAT Rates:

http://taxhistory.co.uk/VAT%20history.htm

Historical Inflation Comparator:

https://iamkate.com/data/uk-inflation/

It would be interesting to know how well the radio performs.

[ms660]

It seems to have an extra control.

Lawrence.

[SiriusHardware]

SMC also made a brief foray into UK CB with the 'SMC Oscar 1', although that is just yet another radio from that period with a Japanese made Cybernet 134 chassis, external styling recycled from Hy-Gain, and an SMC badge on the front.

[John KC0G]

SMC briefly manufactured and sold the Lowe HF-150 RX, and its Europa version. IIRC that was around 1998 when Lowe exited the SW RX business.

In 2000 they were also selling the Fairhaven RD500VX. https://web.archive.org/web/20010510...D500/Index.htm

73 John KC0G / M0KCY

[Geoff G4ICD]

It was the later Trio 9R59DE with no tubes, badged for SMC by Trio which I found in my records/scans, and I closed the Amateur Radio side of things down in 2001/2002 Axminster then Chandlers Ford.