Unknown (Military?) Apparatus. - UK Vintage Radio Repair and Restoration Discussion Forum

Nanozeugma · 19th Jul 2018, 10:27 am

Mornin' All.
When picking up a radio yesterday, I was also offered a large, heavy piece of equipment which bore the legend...
"FERRANTI Sweep Signal Generator LF MkII.
It also bears the identifier 6625-99-972-1383 (1965).
It intrigued me, as it bore the words "sweep generator", but I think it's far from what I thought it might be.
It has six valves inside it: 3x Mullard OB2 108C1 Voltage Stabilisers.
2x STC 5B/254M Beam Tetrodes and 2x Ferranti 12AX7 High Impedance Double Triodes.
The large, circular analogue meter movement on the front panel bears the military broad arrow.
It has two devices inside which appear to be "Muirhead Synchro Resolvers".
It has no internal power supply, and appears to require an external DC source.
I can find no information on this apparatus whatsoever on line.
Googling the words FERRANTI Sweep Signal Generator LF MkII, produces pictures of bloodhound missiles and aircraft, no images of the equipment.
Googling the identifier 6625-99-972-1383 takes you to "natopart.com". The part number is listed but the only option is to "request pricing" - no image.
I wondered if anyone had any ideas what it is?

N.B. I've probably put this in the wrong area, if so, can mods please move it - thanks.

ms660 · 19th Jul 2018, 10:57 am

As a guess, something to do with radar?

Lawrence.

joebog1 · 19th Jul 2018, 11:25 am

It is as it says!!! The synchro resolvers are basically 3 phase motors that will turn in perfect synchronicity with the synchros that it is connected to.
When I worked at CSIRO, ALL the satellite dishes ( Tidbinbilla, Parkes etc) used syncros for alignment.
They are supremely accurate postioning devices.

I think your kit will be associated with a sweep generator that, PERHAPS
Swept with a radar dish
swept with a positioning system

The external power supply I have no idea about, BUT syncros and positioning devices used an available AC source of power. I have a wonderful write up on them, if you will give me a chance to scan and publish here for you.
From memory it was published about 1965, so "fairly recent/modern".

paulsherwin · 19th Jul 2018, 11:36 am

At a guess I'd say it's part of a Bloodhound missile targeting system.

https://en.wikipedia.org/wiki/Bloodhound_(missile)

ronbryan · 19th Jul 2018, 11:51 am

The 23RS4a Muirhead resolvers are size 23 400Hz computing resolvers, rated at 10 to 90V. Resolvers are two phase.

They are still in the catalogue here:
http://www.nasco.co.jp/cms/mark/pdf/.../Resolvers.pdf

Ron

dseymo1 · 19th Jul 2018, 11:54 am

Beautifully made!
What's the component on the left of pic 2, surrounded by a heatshield or screen?
It looks superficially like a dummy load resistor, but I don't see any associated heavy-current wiring.
I was a bit puzzled by the meter scale, too. 10 CPS mid-scale seems too high for a radar sweep, but I then noticed that FSD can be switched to 0.2 or 2, which is more like it. Why have a meter reading 20 FSD, though - it's not as though it's an off-the-shelf scale?

David Simpson · 19th Jul 2018, 12:08 pm

Well worth keeping such a lovely vintage item. If it wasn't used for Bloodhounds, it might be associated with AI23B - the Lightning Radar used for targeting the Firestreak A - A Misiles. Probably a 2nd or 3rd line item. Possibly ex 30MU RAF Sealand.

Regards, David

newlite4 · 19th Jul 2018, 2:29 pm

I have a quantity of these resolvers, mine are made be Smiths Industries, otherwise commonly referred to as Selsyn Transmitters.
Neil

barrymagrec · 19th Jul 2018, 3:10 pm

Those STC 5B/254M Beam Tetrodes are, to all intents and purposes 807s on an octal base.

Nanozeugma · 19th Jul 2018, 5:02 pm

Quote:

Originally Posted by barrymagrec

Those STC 5B/254M Beam Tetrodes are, to all intents and purposes 807s on an octal base.

Yes.
http://www.r-type.org/exhib/aab0149.htm

Bill · 19th Jul 2018, 10:49 pm

ZS74 or 704 1000v power diodes on the PSU boards made at Ferranti Electronics, Gem Mill,Oldham.
Almost certainly this equipment is for Bloodhound Missile system

Graham G3ZVT · 20th Jul 2018, 1:37 am

Look Graham, there's Basil going to work in his helicopter.
Or so my Dad would tell me whenever he saw one overfly our house.

G8HQP Dave · 20th Jul 2018, 9:51 am

Quote:

Those STC 5B/254M Beam Tetrodes are, to all intents and purposes 807s on an octal base.

Not octal, B8B.

Herald1360 · 20th Jul 2018, 7:52 pm

Not international octal but octal nevertheless......

Orakle42 · 21st Jul 2018, 9:25 am

I think DAVID SIMPSON is right, it has all the hallmarks of a piece of ground based but portable test equipment. Are there any other connectors? The only connections visible appear to be terminal posts on the front panel.

Orakle42

Nanozeugma · 21st Jul 2018, 7:21 pm

Thanks for the input folks. I'll upload some photographs of the side and top panels to complete the picture, when I get a minute...

19th Jul 2018, 10:27 am	#1
Nanozeugma Heptode Join Date: Nov 2017 Location: London, UK. Bury, Lancashire quite regularly :) Posts: 611	Unknown (Military?) Apparatus. Mornin' All. When picking up a radio yesterday, I was also offered a large, heavy piece of equipment which bore the legend... "FERRANTI Sweep Signal Generator LF MkII. It also bears the identifier 6625-99-972-1383 (1965). It intrigued me, as it bore the words "sweep generator", but I think it's far from what I thought it might be. It has six valves inside it: 3x Mullard OB2 108C1 Voltage Stabilisers. 2x STC 5B/254M Beam Tetrodes and 2x Ferranti 12AX7 High Impedance Double Triodes. The large, circular analogue meter movement on the front panel bears the military broad arrow. It has two devices inside which appear to be "Muirhead Synchro Resolvers". It has no internal power supply, and appears to require an external DC source. I can find no information on this apparatus whatsoever on line. Googling the words FERRANTI Sweep Signal Generator LF MkII, produces pictures of bloodhound missiles and aircraft, no images of the equipment. Googling the identifier 6625-99-972-1383 takes you to "natopart.com". The part number is listed but the only option is to "request pricing" - no image. I wondered if anyone had any ideas what it is? N.B. I've probably put this in the wrong area, if so, can mods please move it - thanks. Attached Thumbnails __________________ Thermionic Emission, warms the cockles of your tubes.

19th Jul 2018, 10:57 am	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Unknown (Military?) Apparatus. As a guess, something to do with radar? Lawrence.

19th Jul 2018, 11:25 am	#3
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: Unknown (Military?) Apparatus. It is as it says!!! The synchro resolvers are basically 3 phase motors that will turn in perfect synchronicity with the synchros that it is connected to. When I worked at CSIRO, ALL the satellite dishes ( Tidbinbilla, Parkes etc) used syncros for alignment. They are supremely accurate postioning devices. I think your kit will be associated with a sweep generator that, PERHAPS Swept with a radar dish swept with a positioning system The external power supply I have no idea about, BUT syncros and positioning devices used an available AC source of power. I have a wonderful write up on them, if you will give me a chance to scan and publish here for you. From memory it was published about 1965, so "fairly recent/modern".

19th Jul 2018, 11:36 am	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,934	Re: Unknown (Military?) Apparatus. At a guess I'd say it's part of a Bloodhound missile targeting system. https://en.wikipedia.org/wiki/Bloodhound_(missile)

19th Jul 2018, 11:51 am	#5
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,959	Re: Unknown (Military?) Apparatus. The 23RS4a Muirhead resolvers are size 23 400Hz computing resolvers, rated at 10 to 90V. Resolvers are two phase. They are still in the catalogue here: http://www.nasco.co.jp/cms/mark/pdf/.../Resolvers.pdf Ron

19th Jul 2018, 11:54 am	#6
dseymo1 Retired Dormant Member Join Date: Dec 2007 Location: Shropshire, UK. Posts: 3,051	Re: Unknown (Military?) Apparatus. Beautifully made! What's the component on the left of pic 2, surrounded by a heatshield or screen? It looks superficially like a dummy load resistor, but I don't see any associated heavy-current wiring. I was a bit puzzled by the meter scale, too. 10 CPS mid-scale seems too high for a radar sweep, but I then noticed that FSD can be switched to 0.2 or 2, which is more like it. Why have a meter reading 20 FSD, though - it's not as though it's an off-the-shelf scale?

19th Jul 2018, 12:08 pm	#7
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,852	Re: Unknown (Military?) Apparatus. Well worth keeping such a lovely vintage item. If it wasn't used for Bloodhounds, it might be associated with AI23B - the Lightning Radar used for targeting the Firestreak A - A Misiles. Probably a 2nd or 3rd line item. Possibly ex 30MU RAF Sealand. Regards, David

19th Jul 2018, 2:29 pm	#8
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: Unknown (Military?) Apparatus. I have a quantity of these resolvers, mine are made be Smiths Industries, otherwise commonly referred to as Selsyn Transmitters. Neil __________________ preserving the recent past, for the distant future.

19th Jul 2018, 3:10 pm	#9
barrymagrec Octode Join Date: Dec 2017 Location: Morden, Surrey, UK. Posts: 1,557	Re: Unknown (Military?) Apparatus. Those STC 5B/254M Beam Tetrodes are, to all intents and purposes 807s on an octal base.

19th Jul 2018, 10:49 pm	#11
Bill Pentode Join Date: Dec 2005 Location: Denton, Manchester, UK. Posts: 187	Re: Unknown (Military?) Apparatus. ZS74 or 704 1000v power diodes on the PSU boards made at Ferranti Electronics, Gem Mill,Oldham. Almost certainly this equipment is for Bloodhound Missile system

20th Jul 2018, 1:37 am	#12
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 18,710	Re: Unknown (Military?) Apparatus. Look Graham, there's Basil going to work in his helicopter. Or so my Dad would tell me whenever he saw one overfly our house. __________________ -- Graham. G3ZVT

20th Jul 2018, 7:52 pm	#14
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Unknown (Military?) Apparatus. Not international octal but octal nevertheless...... __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

21st Jul 2018, 9:25 am	#15
Orakle42 Pentode Join Date: Nov 2015 Location: Maidstone, Kent, UK. Posts: 131	Re: Unknown (Military?) Apparatus. I think DAVID SIMPSON is right, it has all the hallmarks of a piece of ground based but portable test equipment. Are there any other connectors? The only connections visible appear to be terminal posts on the front panel. Orakle42

21st Jul 2018, 7:21 pm	#16
Nanozeugma Heptode Join Date: Nov 2017 Location: London, UK. Bury, Lancashire quite regularly :) Posts: 611	Re: Unknown (Military?) Apparatus. Thanks for the input folks. I'll upload some photographs of the side and top panels to complete the picture, when I get a minute... __________________ Thermionic Emission, warms the cockles of your tubes.