Early Air Ministry oscilloscope type 11.

[David Simpson]

More great info from VT FUSE. Many thanks. My guess at it having a Cossor-ish look about it has proved correct.
I've crossed referenced the valves :-
V1,2 &4 = 10E/11446 = VR65 = SP61 Pentodes
V3 = 10E/164 = VGT121 = T41 Thyratron
V5 = 10E/582 = 6X5G = F/W Rect.
V6 = 10E/121 = VU120 = SU2150A = Cossor EHT Rect.
V7 = 10E/446 = NU26 = 7448 = CV1274 = Rect.
V8 = 10E/2130 = ?

Now the questions arise - Is there a Cossor Archive anywhere ? - What was the AM equipment ref no of the Anti Aircraft Command Equipment being used in 1952 ? - What is the AP or Manual number ?

Regards, David

[VT FUSE]

A little more detail,despite several counts (!) my scope only has provision for six valves and the CRT,there being no V.8 , the tube,as we know is designated V.7

You are sure to have found by now that the ACR10 CRT crosses to the VCR139A as confirmed on the 'National Valve Museum', site ,it has a couple of numbers allocated,as expected, under the CV Scheme. These numbers being CV1588 and CV1382. Be sure to see the ACR10 link,top of page.

These tubes were fitted in the indicator units of other RADAR equipments and were thus quite numerous,in fact,I see that Langrex Ltd has eight ACR10 tubes in stock (Sylvania-USA) at the very reasonable cost of £31.00 inc post, (no connection or involvement with Langrex,so not advertising or promoting but am a happy customer)

This was all set in the early post War period,all had changed,no longer were we attempting to shoot down smallish conventional Bomber A/C,but moving onto the threats of long range types carrying Nuclear Warheads.

Our very sensible response during this new 'Cold War' was to engage in something of a crash program of Missile type Anti Aircraft Weapons Systems such as the Bristol 'Bloodhound' and fighters carrying the early generations of Air to Air missiles such as 'Red top and Fire-Streak'

Thus,the equipments in use, up to this point became hopelessly outdated overnight.

Hopefully,pics can be organised and posted over the next few days,I have made a couple of incidental discoveries upon examination of my scope (more later) but as yet,no serial number.
Makers names were intentionally not marked on items such as this.

I am inclined to think also,especially given the rack mount facility, that these scopes were more for waveform shape monitoring or even PRF checks?
however,there are persons on this forum who post regularly and much better placed than I am to make suggestions such as these.


Regards

[Brased]

I assume that the advert should have referred to a construction date of 1942. Also I am puzzled by reference to a hard valve timebase. The T41 was designed for use in the line and frame timebases of prewar television sets and was a thyratron. As such it was only suitable for operation at low frequencies.

My unit also only seemed to have seven valves including the CRT. I eventually spotted the V8 marking on the rear of the front panel adjacent to the panel indicator lamp. The designation thus refers to a 6 volt MES bulb.

Edward

[David Simpson]

Even more great info from VT FUSE, many thanks.
My AP1186 says that V7(10E/446) is a NU26, & the VV Museum says that a NU26 is a dumpy odd shaped rectifier.
I've sent off an info request to Raytheon(was Cossor) to see if they have anything in their archives.
Another conundrum - why the wooden cabinet ? Was it just for transportation between fixed rack mounted systems, I wonder.

Regards, David

[VT FUSE]

Brased,
well done on finding that V8 is the indicator bulb,. That aspect can now be 'put to bed' will confirm by checking my unit later if get time but have no doubt as to your being right.

Also agree on your date of 1942 as opposed to advert stating 1952,maybe seller attempting to mislead that equipment was 'bang up to date' or even they were fed duff info themselves?

David,
the ad makes no mention of the very nice wooden case,mentioned using its RAF stores no. earlier in the thread, advert makes mention of steel case.
Very likely the unit was only used rack mounted and the wood case was used for protection when not in rack or steel transit case,this is somewhat confirmed by the back case cover only having 2 simple hasps to secure it-very easy to take a nasty belt if open when powered,also,my unit is a simple slide fit in the wood case with no obvious securing means.

This scope looks like it may very likely be part of the SLC gun laying RADAR that synchronised the 60" searchlight and 3.7" Anti Aircraft Gun to locate,and 'lock follow' a RADAR return from a target (Enemy A/C) The system known within T.R.E. by the name 'ELSIE'
'Boffins' heading project named: Chick,Eastwood and Oxford,commencing 1940 after the London Blitz and in full service 1942-3.

(this info subject to confirmation of course)

[M0FYA Andy]

David,
Key to this going to be finding a copy of A.P.2879AA.
Did you have any luck with Collingwood, and have you emailed Colin Guy, the VMARS archivist?
Andy

[David Simpson]

Andy, Colin has promised to get in touch when he finds something. If he can't find anything I'll contact Collingwood. I'm still waiting to hear back from Henlow & Raytheon(Cossor).
I guess searching for an AP or Manual on the "ELSIE" Radar AA System would be a help, if, as VT FUSE suggests, the Type11 'Scope was part of. Anyone any ideas. I've had a shufti through the VMARS online listing, but can't find anything.

Regards, David

[VT FUSE]

David

have sent you a pm

for benefit of the thread no further detail/info as yet.

Regards

[Brased]

A better front panel photo and a view of 'V8'.

I've started to get interested in this scope. It doesn't seem suited to rack mounting so I wonder what the installation looked like. Perhaps there are photos somewhere.

If the box were purely for transit I would have expected it to have protected the front panel as well. There are four screw fixings on the chassis base and ventilation grills in the case so it could have been used as a free standing unit. However the choice of plywood rather than steel for the casing of a mains powered test unit is unusual but may have been governed by the availability of materials. As VT FUSE says, it is very easy to gain access to dangerous voltages and I cannot find any warnings on my unit.

Edward

[VT FUSE]

Google brings up plenty of images if you search WW2 RADAR guided searchlight or 'ELSIE' LSC even, Yagi beams stacked on 60" searchlights.

Yes,carefully turned my scope upside down after posting-too late of course,and there were the four screw holes minus screws, should have looked first.

Absolutely agree on not being designed for conventional rack mount install,mine has thin steel sheet along sides internally,presumed for screening.

From a glance at front panel legends and considering millisecond time base references,maybe this is some indicator unit for use within mobile cabin etc.

At this stage only info is from direct examination and the PW advert (don't think trading standards really came into such descriptions for 'War Surplus')

Feel that we are making some progress at intended role of instrument.

[David Simpson]

Well folks, looks like the Imperial War Museum has some info :-
http://iwm.org.uk/collections/item/object/3000
Titled RADAR ANCILLARY EQUIPMENT,MONITOR OSCILLOSCOPE NUMBER 11. AA(Anti-Aircraft) PREDICTOR Mk1, BRITISH, but couldn't download the picture.
Stores Ref OS1879 GA s/No ACL 346 Made by AC Cossor. Catalogue No COM370
Alf Fisher, the Curator at Henlow is visiting Duxford today & hopes to get more gen. Fingers crossed.

Regards, David

PS Picture on nest post.

[Station X]

I think this is the correct link:-

http://www.iwm.org.uk/collections/item/object/30005712

[David Simpson]

Just cannot attach the IWM Page. This site keeps calling it "Invalid".

Interestingly, "Humphrey" raised a thread back on 28th Aug.2011, in the Am. & Military section, about an AA Predictor Oscilloscope.

https://www.vintage-radio.net/forum/...ad.php?t=73529

Regards, David

[David Simpson]

Its possible that the Scope shown in Humphrey's thread is the same as the one referred to in the IWM article. The ref nos are identical. A much more modern scope than the old thing we're researching. Late 50's/early 60's I would think.
Our old wooden-cased thing has a basic thyratron timebase, which I suspect pre-dates the triode/pentode T/B in the original pre-war Cossor3339 & the 1941 339 with its triode/two pentode T/B.
After the Blitz in 1940, the AM must have rushed through the development of a basic single beam LF scope for Predictor usage. It was no doubt obsolete in the early 50's cold-war period. Hence being replaced by Humphrey's more modern scope. Why the AM kept the "Type11" designation, I don't know.

Regards, David

[David Simpson]

Late night update, I'm over the moon. Alf Fisher, the Curator from the RAF Henlow Signals Museum has acquired all the gen on the scope from Duxford today. As soon as I get it I'll make it freely available to the other Type 11 scope owners & the Forum in general. Brilliant work, Alf.

Regards, David

[M0FYA Andy]

David, excellent news!
Andy

[Brased]

Well done David! That is really good news.

Edward

[David Simpson]

Copy of AP 2879AA Vol.1 arrived today. About 15 pages. Thought I'd put out three of them just now. More to follow.
As thought, this looks like a smaller & simplistic single beam version of the original 3339.

Regards, David

[Nymrod121]

I've just finished reading through this thread - a fascinating series of contributions & a great result.
Well done!
Guy

[VT FUSE]

An excellent result David,Alf most certainly got the info.

Any info as to what Anti Aircraft Command were using these for?

My scope is identical in all respects to the photo in above info,complete down to hood and lettering on front panel.

Regards- please thank Alf from me as well