New Acquisitions

Low Voltage Stabilised Power Supply

 

 

 Doolittle PR7NA

US Navy receiver made in 1944

 

 T4188 Transmitter

These were fitted in the V-bombers

 Click the picture to see more

Reference Battery 

This rather strange set-up is battery made up from laboratory standard reference cells. These things are not designed to supply power, in fact in the days before high resistance digital testmeters it was strictly forbidden to attempt to measure their terminal voltage.

These examples are all marked 5154B, 1.01859 volts @ 20 deg C and made by Tinsley & Co
 

 A Resistance Bridge made by Elliott Brothers

 An RA1B receiver made by Bendix in the USA

click the picture to see more

 A Korean War transceiver, the RT77A/GRC-9

click the picture to see more

 

 A Lissen Kenilworth with push-button tuning

 

 AWA Radiola Super

click picture to see more

 A WW2 Power Supply Unit Type W7684

This was used in the CNY-2 Equipment

 

A type 76 receiver complete with its transit case

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 Two recently acquired radios

click either picture to see more

 
 

and see a pair of early HT batteries


 

This has been propped up on our window ledge pointing up the stairs for the best part of 25 years.

Does anyone recognise it?

Pictures of recent additions


RF24B and an RF26B

Click the pictures to see more details

 


Philips HT Supply Unit 3005

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The Lancaster Transmitter, T1154

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 The Jopeka Crystal Set

click to see more

 

 WS19 MkIII

click picture to see more

 

 R206 MkI

click picture to see more

 


Paperweights

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Receiver R1147A

 I bought this on 2nd April 2015 as a birthday present for myself. For some strange reason no-one else bothered to bid for it so it was mine for £30.

The set is a beacon signal homing receiver originally designed for use in the Fleet Air Arm in the Seafire but was tried out by the Royal Air Force and redeveloped for use in photo-reconnaisance Spitfires during 1941 and 1942. It was replaced by the TR1133 in these aircraft around the time I was born, but was thought to have been used later in the Beaufighter.

The set could be tuned by a remote control device connected by a cable to a similar device which turned the tuning condenser in the set. I bought one of the slow motion drives from a government surplus shop many years ago and always wondered what it had been used for.

The set operates in the VHF range tuning from 180 to 220Mc/s and uses British or American acorn valves, one VR59 (type HA2/955) and three VR95 (type ZA2/954) plus a pair of VR56 (type EF36) and a single VR55 (type EBC33).

 

click the box to see more


Columbia Model C302

 This post war receiver was probably introduced around 1949. It's not too common and data is quite scarce.

Steve Dent from Fareham very kindly delivered it to me recently. I understand it belonged to his mother who, like me, worked for Plessey.

It's very typical of the late 40s to early 50s having three wavebands. I'll look inside later and see if I can spot a date. Alas, these type of sets do not command a high value as you may see if you search for ithis model on the Net. One sold on Ebay recently for the princely sum of £5.50 and cost the new owner over £15 in postage.

 

As you can see it's designed for AC mains.

 And here's its plastic label showing Serial Number AD50530 and you'll notice that Mr Marconi's family have taken their cut, although the wording isn't exactly specific on that point. Presumably, by this time Marconi had persuaded British and Irish manufacturers that they must be licensed by them in order to carry on their business and to pay royalties on the volume of their output. Perhaps the first stealth tax? I wonder how this tax was collected on imported items?


W2508 Wavemeter & Crystal Calibrator

 This interesting-looking box has several parts which are used on other pieces of WW2 equipment.The main tuning control and the various knobs can be seen on the WS No.18. Overall, the box reminds one of a 52 Receiver, the lamp at the top left like the one used in the WS No.17 and the co-ax connectors are the same as that on the WS No.19. Not surprising as Pye made the 19 set as well as this wavemeter.

The main tuning control has a vernier allowing a reading of three significant digits. The wavechange switch is marked as follows:-

Range 1 100-290Kc/s: Range 2 280-900Kc/s: Range 3 820-2400Kc/s: Range 4 2-6.4Mc/s: Range 5 4-12Mc/s: Range 6 12-25Mc/s

I haven't checked yet, but the wavechange switch feels like a turret tuner. Although a lot smaller, this might be like the turret in the R206.

What are the innards like?

A view inside...pretty dull really...

The crystal calibrator is marked "1942", a special year.

Nice screening for the attenuators and, buried behind the power supply upper right, a VR56 modulator valve (an EF36)

 

 A neat feature is the crystal oscillator and the power supply can be each be detached by removing sets of three knurled screws.

The rear cover, I think held a calibration chart, which is now missing.

A search on the Net reveals an Australian Navy document which includes the information about Wavemeter Outfit GN below...

The thing weighs in at 32 pounds so would have been ideal for installation on a battleship... as indeed it was according to the information preceeding this...

(c) Wavemeter G73 complete with Oscillator G42-Pattern No. W2508.-
A wavemeter and oscillator, designed in 1941, which combines the functions o f:-
(i) A portable heterodyne wavemeter.
(ii) A signal generator for receiver tests.
(iii) An audio frequency test oscillator.
When employed as a wavemeter it may be used for checking the approximate
frequency of an unknown transmitter or for transferring to a receiver or transmitter
an exact frequency obtained from a wavemeter G35, G61 or G62. An oscillator G42,
consisting of a 1-megacycle crystal controlled oscillator, is mounted inside the
wavemeter G73 and is used to provide a means of checking the calibration of the
G73 when a standard wavemeter outfit is not available.
Frequency range ... 100 Kc/s-25,000 Kc/s.
Power supply ... (i) A.C. 115, 125, 200 or 230 volts, or
(ii) D.C. 6 volts and 100 volts.
The power pack or batteries are carried inside the set.


Racal RA17 Mk2

 I picked up this Racal locally in September 2014. It was said to have no audio but I think that's just dirty valve pins as it came to life after plugging it in and waiting ten minutes. After this it seemed lively but very deaf and intermittent. Hopefully just bad valve connections, but it will need an overhaul, I'm sure. The Megacycle dial tunes nicely and the response is definite but perhaps a bit lopsided?

The main problems are not too serious, lack of plastic or glass behind the escutcheon and the labelling on the front panel is pretty worn. From the wear on the switch toggles it's had a useful life. Somewhere I have a decent escutcheon if this one does scrub up well. Cleaning the panel will be awkward as most of the labelling is well worn and not all appears to be engraved.

See its refurbishment

 The set came with a balun that seems to be 600 ohms to 50 ohms plus a mains lead and aerial lead, both usefully fitted with correct plugs.

 

Wireless Set No 52

Last week (September 2014) I bought the 52 Receiver shown below

See details for this set


A second R1132A

see it's refurbishment...

Toyo 100Watt Dummy Load

 A useful dummy load which turned up recently. I wonder why it's spec starts at only 3.5MHz and what's the significance of "M" and "N" on the curves? This has a PL259 socket so I wonder if "N" implies there's a version with an N connector?

 


Milliameter

From the chalk it looks like this anonymous meter suffered a catastrophic problem?

 Fortunately not dead though. After a fall the needle had jumped out of its bottom bearing and the coil had jammed in the magnet gap.

An hour or so with steady hands had the meter back to a working state with all ranges seemingly accurate. Just a little white filler in the engravings for the ranges and it'll be as good as new.

 

 

Trawler Band Receiver

What is it? Click the picture to see more

 WW2 Short wave receiver?

I decided to give a new carrier a try because my usual carrier the Post Office or Parcel Force are getting too expensive for heavy items (£33 for 16Kgm with £100 insured value) and as this radio was said to weigh around 16Kgm I selected Yodel.

Yodel offers collection plus delivery for the same price, so I found their website and parted with around £10 on Monday 9th March 2015. I'm not sure of the figure exactly because their feedback paperwork omitted to tell me how much I'd paid, but I got two follow-up emails offering to fully insure my parcel, but I reckoned any potential damage would be covered. I must admit I'd not anticipated the parcel going missing or being stolen, but surely that's not likely.

The next day, Tuesday 10th, I had notification the parcel had been collected at 9am, so things were looking promising, however on Wednesday 11th March, the day I'm expecting delivery, I went to the web-page and typed in the consignment code which I was told would begin "JJ" and my postcode and was informed the system didn't recognise the numbers. I called Yodel's phone number and followed their procedure of talking to a computer with voice recognition but no luck and was transferred to a young lady who couldn't trace the parcel either. She could see it had been collected but didn't know what was going on as the consignment number was unrecognised. I was promised a call back and I'm still waiting for this, however the explanation about tracking details being late was probably correct as...

I thought I'd go back and try tracking the parcel again. This time I was presented with a different Yodel page with a different style of tracking number beginning "YOL", entering this I was given the information the parcel was on it's way and due today, 11th March. I also spotted a link to an invoice and tried this. The total was £10.55p for an insured value of £20. For interest I also entered the JJ number and this was accepted, giving the same info as the YOL number. It seems the two tracking methods, on different web pages are unlinked until details have been entered by their clerical people?

All was well. The box was delivered about 1pm on the Thursday, all intact.

 

Oscilloscope

 My pal Brian Hill (another Plessey retiree) made this oscilloscope when he was training in the Navy at HMS Collingwood in the early 1970s. He tells me he wound the transformer and engraved the front panel but admitted to not making the components or the valves. I'll remove the lid later and take a look inside then see if it still works.

click the picture to see more


 Cosmos Radiophone Crystal Set

made by Metropolitan-Vickers Electrical Co.Ltd.

 
   Just an empty box alas, but a perfect interior instruction label and a decent Post Master General type approval badge.

 

 The instruction card is quite interesting. First one must ask why the aerial emerges from the front of the house rather than the more discrete rear? Presumably possession of a wireless aerial in those distant days was considered a status symbol?

Although the aerial would be visible the receiver would not, and it's worth pointing out that this humble crystal set was considerably cheaper than those sets currently available at the time employing valves, which could cost as much as a years wages of an ordinary worker. Not that anyone would ever spend a years wages on a receiver but you get the drift.

Having shelled out more than two weeks grocery money on one of these crystal sets, and coughed up for a license (well you did put up this 100 foot advert for your receiver in your front garden didn't you!), the intial mastering of the operation of a crystal set was quite a technical achievement. Basically one fiddled simultaneously with a cats whisker and a tuning knob until a sort of ethereal hubub of voices was heard. Getting the crystal to work was a bit hit and miss... note the comment about giving up and trying the spare one! There were so many hurdles.. was the aerial connected properly? Did the crystal work? Was the cats whisker OK, and in contact with a suitable point on the uncertain crystal? Were the headphones working and connected correctly?

Of course, once initial success was behind one, in retrospect, it all seemed easy.

Tuning in this model was carried out with a "handle" that connected to tappings on a coil, which in conjunction with the aerial, resonated roughly at the frequency of the desired station, and once adjusted resulted in one station becoming slightly louder than lots of others. Daytime listening was a lot different than night time listening. During the day one would really only be able to hear one or two stations but, at night, when the sun went down, the airwaves came alive with dozens of strange foreign voices, often turning into English at pre-arranged times, as the continental stations were very aware of their avid British listeners and published programmes to suit.

Because of the very low average level of technical skills in wireless reception in the early 1920s, tuning a station was generally not an easy matter. First one had to have constructed a suitable aerial, a device covered by government legislation dictating that it was not to exceed 100 feet from distant tip to receiver terminal. Secondly, for decent reception a good earth connection had also to be made and, if one listened to the proper authorities and advertisers, it was pretty well essential to include a safety switch to minimise electrocution from lightning. There were also articles on making provision for getting the wire into one's house, using suitable porcelain insulators and the like. Next came the intricasies of connecting up the aerial and earth wires and headphones. In fact there were lots of pitfalls on the way to settling down and listening in. Once an enthusiast was successful and had demonstrated his prowess to his own family, no doubt he became a consultant to his neighbours.

 

 
 The use of a loudspeaker in those early days was rare, and most listeners used headphones. It's worth pointing out that these headphones were very different to modern types. Crystal set headphones were high resistance instruments that would offer a relatively low loading on the simple crystal set circuitry (equals loud reception). Note that the instruction label above mentions the fact that two pairs of headphones can be used but implicit in the directions for their connection is the fact that these are wired in series not in parallel. Modern headphones are useless for crystal set use because they have a very low impedance. This would result in only a tiny fraction of the available radio signal getting to the listeners ear (equals very quiet reception), and anyone experimenting with an old crstal set would be very disappointed with the results unless high impedance headphones were used.

 The Spiralarm Lamp

 

 

 When I bought this funny looking lamp from a junk dealer at Wimborne Market I thought it was a Miners' Lamp but I've now discovered it was used in sewers to detect gas. I don't know why this is needed as I imagined that all sewers are filled with gas anyway but presumably it's used as a means of letting the chaps that visit such places that the level of gas is too high for safety?

Click the lamp to see a bigger picture

The Spiralarm has the maker's name J.H.NAYLOR, WIGAN and has Type "S" marked on the label. I understand the Type "M" was used in mines and has a slightly different characteristic so that the gas type and percentage that it detects is different.

The patent number is given on the label as 352267.

http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB352267&F=0

reveals the patent details, from which can be seen that the design dates to 1931. I should think that my model is rather later than that, but I shall leave that to experts in the matter.

Operation is relatively simple. In the presence of an inflammable gas in the surrounding air the flame gets bigger and heats a bimetal strip which operates a set of contacts, turning on a lamp in the lower compartment.

The materials from which the lamp is chiefly constructed are aluminium (or one of its more robust alloys), and brass.

As you can see a spare wick is looped around the base.. in fact it's possible that the lamp has never been used and the original? wick never fitted.

Clipped onto the base is a mirror made from chrome plated steel.

A knurled brass adjuster is located underneath the base. This presumably to enable the flame height to be preset and to allow for wick to be raised when it's burned down.

 An old REVO electric fan from the early 1930s I think?

 

 

 This came fitted with an old two-pin 2-amp plug commonly used before WW2 and, on the underside, the makers' name "Revo" Model? "12" and Serial Number 62384.

 

It bears a marking for 200 to 220 volts 50 Cycles but etched next to this is "240 volts".

 

I haven't plugged it in because the wiring is a bit too brittle for my liking.

 

I think there are plenty of Electric Fan followers out there so maybe one would care to comment on the Revo's true age?


Sony CDP101

I was tidying up the workshop when I found an old CD player. It was left over from the days I used to repair such things and I recall this particular thing belonged to me rather than a customer. Repairing CD players was a tricky business. Usually one could buy a complete optical mechanism for a few pounds and drop it into place and the player would work like new, however, some manufacturer's models used very unusual optical units whose replacement cost well over a hundred pounds. These equipments were automatically consigned to the scrap heap because prices on new players had dropped to less than £30.

For some reason I'd kept this Sony player and today I looked it up on the Net. It turns out to be the first commercially produced CD player so is definitely worth keeping. These players sold originally for over £500 in 1982 and working models still fetch well over £100.

Some old valves

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