Help identify RAF receiver please.

[G4XWDJim]

This compact 8 valve receiver covering 3.1 to 7.0 mHz is labelled as Air Ministry Receiver type 6A. 10P/13014. It bears a passing resemblance to the Four Square receiver type 78 but is I think more comprehensive.

It has 5 EF50, 1 6K8 and 2 EF39. The two gang capacitor tunes the front end and the two stage roller coaster provides main tuning. The heaters appear to be wired in series for 12 volt operation.

Thoughtfully the designers made the side panel hinge open for easy servicing. There is a parts list fastened inside the outer case but no circuit diagram.

Does anyone know where and for what it was used. They seem to have gone to some lengths to keep the 6K8 securely in place with a spring loaded screening can. Anti vibration perhaps?

Might anyone have a circuit diagram. I've never found one in the many years I've had the set. I think it's time to pass it on to someone else but it would be good to see what it's capable of first.

Jim

[AC/HL]

I'd guess it's an HF comms receiver for an aircraft. I should imagine it's highly collectable as it's certainly not common.
Unusual calibration, thousands of Kilocycles rather than Megacycles.

[Electrone]

The technical details of this would have been in an Air Publication The RAF Museum holds about 60,000 copies of Air Publications covering a wide variety of equipment used in the RAF. If you send in an enquiry with the details of the receiver you have it's just possible the museum staff may be able to locate a copy of the AP which covers this. Visit http://www.rafmuseum.org.uk/research...lications.aspx. This is somewhat of a long shot but worth trying.

Michael

[M0FYA Andy]

Jim,
I think you will find this is the receiver part of TR1161, covered in AP1186, Volume 1, Section 2, Chapter 9.
As you say, it has a lot in common with the Type 78 in the way it is built, clearly another STC product
Andy

[Radio Wrangler]

British series numbers all over everything, but a frame and front panel that look very American. The EF50s make it certainly British, not a renumbered import. Definitely designed by someone American-inspired, but with a British set of parts bins. The overlap of top-capped octals with the EF50s is interesting. I think we're looking at something from either the very end of WII, or soon after, because the avionics industry went quickly over to the B9A B7G as soon as they became available because of the size and weight.

For a receiver, there's a lot of expected controls missing, so it must be a plug-in F unit for something larger. The tuning scale seems to have multiple bands, but there is no bandswitch.

Not seen anything like it before

David

[RobinBirch]

David,
I think the tuning scale is one continuous "snail". Is there a pointer that moves out as that long coil is varied?

And thanks again for the lovely evening.

Kind regards

Robin

[AC/HL]

A bit in this interesting Australian magazine. (Big download)

http://www.google.co.uk/url?sa=t&rct...,d.ZG4&cad=rja

[G4XWDJim]

Originally Posted by M0FYA Andy

I think you will find this is the receiver part of TR1161, covered in AP1186, Volume 1, Section 2, Chapter 9.

Andy,

Many thanks. Have I ever told you you're a whizz kid!!

I've never known it was part or TR1161 so consequently I've never known that the info has been sitting on my shelf for many years. I have quite a bit of AP1186 I photocopied myself about 35 years ago when I worked for Xerox.

Here's a pic or two of the relevant details and like David says some of the controls are mounted separately. There's a 10 pin Jones plug on the back.

It's good to know what I've got at last.

There are some very dodgy wax capacitors there that will most certainly will need changing so I don't think I'll disturb it now that I've found out what it is. I'll leave that to the next owner.

There's a moral here. Always look on your own shelves.

Jim G4XWD

[G4XWDJim]

Originally Posted by AC/HL

A bit in this interesting Australian magazine. (Big download)

Thanks for that. Well spotted. Page 16 is the key page.

Jim

[M0FYA Andy]

Jim,
I just had a look at my copy of AP1186 (mine is the one advertised as a CD in Radio Bygones), and have realised that the circuit diagrams for the Rx and Tx are missing for the TR1161, so I'm glad you've attached copies for the Rx! Do you have the corresponding Tx circuit by any chance?
I've got a couple of examples of the Rx in very scruffy external condition, and a very battered control unit, but no other parts.
Andy

[G4XWDJim]

Yes Andy, but I'll send them all to you privately so you can get better resolution than the tiny pics I've posted.

Jim

[G4XWDJim]

Originally Posted by RobinBirch

I think the tuning scale is one continuous "snail". Is there a pointer that moves out as that long coil is varied?

It is 'snail' like. Here's a couple of pics showing each end.

Jim

[Radio Wrangler]

Ah, thanks. One band indeed, and it uses a roller inductor for tuning.... I'd have thought that might be a bit jumpy and prone to a bit of backlash.

It's certainly an unusual receiver.

David