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Old 4th Oct 2019, 9:19 am   #41
allan
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Default Re: Moreton Cheyney

Very interesting om and I've never looked into those receivers you mention. Now that I have looked them up I can see the similarities and the AW125 does look very similar to the Moreton Cheyney. The T69A front layout and bandwidth markings 5/10/15/20Kc looks very similar too. It would be interesting to see the exact dates for the Armstrong and Dynatron sets. Usually established companies products evolved from early days with new bits being added as time progressed.
I checked on the candidate (Albert Moreton) for leading the MC company a little more. Not entirely convincing. He was a tinsmith and later a retail shopkeeper (no info yet on what he sold) but the family address in 1939 was only a quarter mile from the Gaol Street address at 1a Rowley Street. The son James Henry Moreton (born 1902), whose mother's name was Annie Cheyney, might be the better candidate and is a bit of a mystery. The dearth of info may mean he emigrated (as you are no doubt aware, both Australia and NZ had schemes for attracting people). Another interesting snippet is the daughter Muriel married a chap called Tarry in 1936 but appears to have ditched him and changed her name by deed poll to something entirely different which implies the Tarry family were not in the Moreton's good books. Tarry called the creditors meeting and she may have blamed the messenger?
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Old 4th Oct 2019, 11:30 am   #42
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Default Re: Moreton Cheyney

I bet they'd never thought we'd be analysing their lives decades later via the internet!
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Old 4th Oct 2019, 1:05 pm   #43
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Default Re: Moreton Cheyney

You're right Nick.. and I bet the eldest son never imagined I'd discover he was illegitimate, born 6 months before his mother married.
I've found a few more points which seem to build up evidence... read on
Allan G3PIY
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Old 4th Oct 2019, 1:40 pm   #44
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Default Re: Moreton Cheyney

Keep up the good work Allan, this has been an absorbing detective trail, as said.

Looking at your block diagram on Radiomuseum, this tuner was certainly an ambitious undertaking that tried hard not to leave any stones unturned. It would certainly have made an excellent broadcast monitor with aspirations of fidelity beyond most comms receivers. As Synchrodyne says, there is a definite stranding between these two classes of receiver- a few, such as GEC's approximately contemporaneous BRT400, managed or endeavoured to straddle the divide, I wonder how this large, heavy and quite complex set compared in price.

The two sets of gang capacitors and their gear-train are striking features- the gang capacitor must have been one of the more expensive single components of any set, apart from the mains transformer, and the tuning drive was presumably bespoke. That investment would have been a very brave step for what appears to have been a small start-up. Both the Marconi CR100 and RCA AR88 had geared tuning drives with a good reputation for feel and resolution- but these were mass-produced professional receivers with a hefty price tag from major companies that had been established for decades. As I said earlier, this design does give an impression of trying a bit too hard.

There's an element of split personality in the tuning scale presentation, too- whilst it goes as far as 30MHz, (as opposed to 26.5MHz to span 11m broadasting) with its implication of amateur radio listening and "communications" pretence, the calibration at this point is in 3MHz chunks with no apparent sign of a high-resolution logging scale that would be necessary, or at least very useful and pretty much an expected feature really.

I think that there will be quite a few of us watching with interest, both from the technical and historical aspects,

Colin
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Old 4th Oct 2019, 6:47 pm   #45
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I'm totally perplexed about the two 3-gang tuning-capacitors: they look to be both of the same sort-of value - is this really *five* signal-frequency tuned-circuits and a LO? If so it'd be a really-unique radio.
Telefunken's famous E52 HF communications receiver had a six-gang tuning-capacitor set for five signal frequency circuits (single-tuned aerial, bandpass 1st RF, bandpass 2nd RF) and LO, it also even had a "PTO" coupler at one end of the gang and available at one end of the case for simultaneously tuning a loop aerial or other ancilliaries. ISTR that Telefunken kept up the many-gangs tight front-end theme post-war with double-tuned bandpass arrangements between RF stages, not sure how many gangs this involved in various models.
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Old 4th Oct 2019, 8:46 pm   #46
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Default Re: Moreton Cheyney

Back in 1953, my mother was in a Stafford hospital, so I would walk along the roads in this part and new the area quite well. (forgotten most of it now).
Walking towards the town centre, I recall an old style junk shop/surplus radio shop where I bought the odd item if pocket money permitted.
Now mention is made of E. A. Boult who was the landlord of 52a. Not so far away in the next street (or next but one) was E.A.Boult, motor cycle shop.
I had not caught the motorbike bug back then, but in the late 50's and early 60's I visited it quite often. If memory serves correctly, it was E.A.Boult who later opened a M/C shop in nearby Stone which I also visited, late '70's then.
Les.
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Old 4th Oct 2019, 11:36 pm   #47
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Telefunken's famous E52 HF communications receiver had a six-gang tuning-capacitor set for five signal frequency circuits (single-tuned aerial, bandpass 1st RF, bandpass 2nd RF) and LO, it also even had a "PTO" coupler at one end of the gang and available at one end of the case for simultaneously tuning a loop aerial or other ancillaries. ISTR that Telefunken kept up the many-gangs tight front-end theme post-war with double-tuned bandpass arrangements between RF stages, not sure how many gangs this involved in various models.
The larger tuning condenser connects to LW, MW and the 40-100m band and the smaller one to the two other shortwave bands via the wavechange switch. Nothing very exotic.
And the custom made gears do look like they were made in a motorbike shop.
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Old 5th Oct 2019, 1:48 am   #48
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Very interesting om and I've never looked into those receivers you mention. Now that I have looked them up I can see the similarities and the AW125 does look very similar to the Moreton Cheyney. The T69A front layout and bandwidth markings 5/10/15/20Kc looks very similar too. It would be interesting to see the exact dates for the Armstrong and Dynatron sets. Usually established companies products evolved from early days with new bits being added as time progressed.
As far as I know, the Armstrong AW125PP was released during 1939, so would have had a short production life. The EXP125 was added to the post-WWII range in time for Radiolympia 1947, advertised in WW 1947 October. It was replaced by the EXP125/2 as part of the substantially reworked Armstrong Radiolympia 1949 range, advertised in WW 1949 October, and still priced at £33.6.

The Dynatron T69A/LF59 Ether Conqueror appears also to have dated from Radiolympia 1947, and was advertised in WW 1947 October. As best I can work out, its replacement, the T99/LF612 Ether Conqueror V, was first advertised in WW 1951 October, but I havenít seen that advertisement.

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Originally Posted by turretslug View Post
Looking at your block diagram on Radiomuseum, this tuner was certainly an ambitious undertaking that tried hard not to leave any stones unturned. It would certainly have made an excellent broadcast monitor with aspirations of fidelity beyond most comms receivers. As Synchrodyne says, there is a definite stranding between these two classes of receiver- a few, such as GEC's approximately contemporaneous BRT400, managed or endeavoured to straddle the divide, I wonder how this large, heavy and quite complex set compared in price.
The BRT400 was £120.00 in 1949 Ė professional class pricing I think. It was known to have been used in HF broadcast relay service, before the change to point-to-point SSB/ISB receivers for this purpose. It was also an optional fitting in the GEC Export Club Radiogram, for which one of GECís domestic receivers was the normal fitting. The BRT400 went through an iteration or two, but stayed in place until superseded by the solid-state RC410/R in 1967.

To round-out the contemporary price comparison, the Peerless 1546 receiver was £50.40. This was broadly similar to the MC, but had a single chassis, a four-gang front end (bandpass input) and a tetrode push-pull output. It also had a full communications specification in that it had a crystal IF filter and a BFO. IF bandwidth choices may have been more limited, though. Peerless advertised in WW from 1946 November, and subsequently introduced some lesser models. It was at Radiolympia 1949; the WW report of which in 1949 November was its last mention that I can find, so presumably it was wound up very soon thereafter.

No price given, but the Mullard GFR520 was also displayed at Radiolympia 1949. This was another broadcast/communications combination that covered 0.54 to 110 MHz AM and CW, 27 to 110 MHz FM, with AM IF bandwidths that ranged from 10 Hz (crystal filter) to 25 kHz. It looks to have been similar to the Hallicrafters SX-42 of 1946, but with a wider maximum AM bandwidth. (I wonder if it used the EF42 or EF91 in the front end?) That was its only apparent mention, so it may not have fared too well in the marketplace.

Returning to the MC, it will be interesting to see how the AGC system was configured. From the viewpoint of high quality reception, separating the delay function from rectification, to avoid differential distortion, was considered to be a desideratum, as was having fractional or zero AGC bias applied to the final IF stage to minimize modulation rise distortion. Delaying the RF AGC more than the IF AGC was an approach to getting the best quieting curve, but not so common, I think. (The GEC BRT400 had this, as did the Ekco A182 domestic receiver.) Fractional or zero AGC bias on the mixer was used to minimize pulling at HF. All features on one receiver would be very rare, I think, but one would expect some of the above on a receiver at the MC level.


Cheers,
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Old 5th Oct 2019, 11:53 am   #49
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Default Re: Moreton Cheyney

Nice to have some background info on this era.
Once FM broadcasts appeared the whole situation must have changed quite dramatically (I modified an ARR3 donkeys years ago to listen in... remember that sonobuoy receiver "used by BBC engineers").
I'm bashing on trying to trace the MC circuit and noticing changes as I do this which makes it difficult to know exactly what the original wiring was. At the rear where the interesting audio processing takes place the area is crowded with components and brittle insulation over 18SWG wiring making it awkward.
I'm uploading sections of the circuit as I go and I'm slightly puzzled by the output stage(s). I suspect the two 6J5s were designed to supply a pair of 90 degree signals to the external amplifier but as only one output wire is now in place one valve looks superflous.. yet both have potentiometers in their grids. The circuitry is only provisional so not guaranteed!

I assumed the 150 volt stabiliser was for the oscillator valve but it looks like its output goes instead to the audio stages at the rear of the chassis. I guess stabilising the oscillator would be a waste of time anyway because of the large pass band of the IF strip? So why bother with an 0D3?
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Old 5th Oct 2019, 1:25 pm   #50
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Default Re: Moreton Cheyney

The 6J5's most likely formed a long tail phase splitter. An obvious change is the introduction of the ganged potentiometer as you can see the drive shaft no longer runs straight - easy to put back. You have to wonder why all this was done? Should be simple enough to put the phase splitter back but you would need to investigate the other chassis to see what is going on there first.
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Old 5th Oct 2019, 7:30 pm   #51
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If one of the tuner front-panel switches has an "AGC OFF" position as mentioned in the Radiomuseum write-up, then maybe one of the potentiometers in the gear-ganged arrangement is an RF gain control, with the other being a conventionally-arranged AF volume pot- these two parts of the circuit possibly required somewhat different component values and the gear-coupled arrangement might have been easier/cheaper with small-scale production than having a ganged potentiometer made up with different value sections. This arrangement of a two-gang volume potentiometer having AF pick-off and signal-frequency (RF/IF) bias sections wasn't at all unusual- the USAAF BC348, the USN's Scott RCH and the Bendix RA-1 are examples with this arrangement, contacts on the AGC on/off switch choosing whether volume was decided by AF potentiometer or RF/IF biasing.
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Old 6th Oct 2019, 12:08 am   #52
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Default Re: Moreton Cheyney

I guess its time to trace the circuitry around those two pots. Combined AF/RF gain might be feasible?

The valve I think is the "TRF receiver" is fed from early in the IF strip and I recall had a KTZ63 plugged in but I think Pin 6 is used which doesn't seem right. I thought it might be an anchor point but its a screened wire by itself. An octal-based valve with top cap and Pin 6 used? I may have misread this but maybe a double diode pentode with g3 strapped to cathode? Maybe a 6B8 but that would make Pin 6... g2? Maybe a magnifying glass is called for...
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Old 6th Oct 2019, 11:22 am   #53
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I solved this mystery. A KTW63 or KTZ63 pentode is strapped as a triode with Pin 6 of the IO holder a tie-off point. The circuit is quite interesting as the valve is run at a very low anode current coupled with a very high negative bias to make it work non-linearly.
I've sketched the wiring for interest.
Allan G3PIY
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Old 6th Oct 2019, 9:10 pm   #54
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Default Re: Moreton Cheyney

It looks as if it might be the infinite impedance detector, fed from the interstage tuned circuit. That would make it a single RF stage, two-gang TRF arrangement for wideband local reception.

Cheers,
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Old 6th Oct 2019, 9:33 pm   #55
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Default Re: Moreton Cheyney

Yes, I'm definitely thinking infinite-impedance detector.

Not only would it give good quality [by virtue of its inbuilt near-100% negative-feedback at AF] but also it reflects the lowest-possible load onto its upstream RF tuned-circuit, so said tuned-circuit's selectivity isn't compromised by damping as would be the case with a classic diode-detector.

I remember building - in the 1960s - a TRF MW radio that had two EF50s as RF-amps, an infinite-impedance detector using another EF50, an EF50 and 6V6 being the audio-stages. It was good for listening to Luxembourg, but the lack of AGC made it tiresome if there was any fading.

At least with the 'classic' superhet diode-detector yiou get AGC-for-free.
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Old 8th Oct 2019, 3:26 pm   #56
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A little more circuitry added to the web page but with that 18SWG wiring cracking insulation and dry solder joints and layers of components it's a battle to get anywhere.
Can anyone identify these diodes (both inside IFT4 can)?
Allan G3PIY
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Old 8th Oct 2019, 4:52 pm   #57
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Default Re: Moreton Cheyney

Can't help with the diodes directly, but they look the same as the one used in the 'noise limiter' of my Eddystone 840A - which having lived for 60+ years had evolved from being a diode and was instead better described as an 'asymmetric resistor' - 70KOhms in one direction, 30KOhms the other - meaning it worked great as an attenuator but uselessly as a noise-limiter.

I replaced it by an OA47 Gold-Bonded diode.
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Old 8th Oct 2019, 5:26 pm   #58
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Default Re: Moreton Cheyney

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A little more circuitry added to the web page but with that 18SWG wiring cracking insulation and dry solder joints and layers of components it's a battle to get anywhere.
Can anyone identify these diodes (both inside IFT4 can)?
Allan G3PIY
They look very similar to the miniature version of the Westinghouse "Westector" diode:

https://americanradiohistory.com/hd2...22westector%22

Lawrence.
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Old 8th Oct 2019, 6:07 pm   #59
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You're right Lawrence.. thanks. They have a "6" underlined which presumably equates to the 6-element version.
I'll no doubt be replacing these with decent germanium diodes as well...
One each for signal detection and AVC rectifier.
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Old 8th Oct 2019, 6:18 pm   #60
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Intrigued that, having been pretty profligate on valve count, they then didn't just add in a D61/EB34/6H6! Maybe Westectors were plentiful as surplus from some wartime requirement, or were simply familiar from e.g. Civilian Receiver use.
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