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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 8th Mar 2023, 3:11 pm   #21
ms660
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Default Re: Question Murphy B40 Power Supply

No problem, here it is after being cleaned up, I built a substantial bench for it to sit on..! The jacket hanging on the back of the chair is my original leather Wrangler jacket which I bought around 1966, it still fits....just about!

Good luck with the research.

Lawrence.
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Old 8th Mar 2023, 5:49 pm   #22
ToonMurphyB40
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Default Re: Question Murphy B40 Power Supply

Concusion of measurent results:
Measurements show that in the mains frequency range of 40Hz - 60Hz the ‘ripple attenuation response slope’ is flat within 0.6 dB.
Result:
There is no need to readjust C316 // C317 of the (L304) resonant filter.

Toon. PE1NHP
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Old 8th Mar 2023, 5:54 pm   #23
ms660
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Default Re: Question Murphy B40 Power Supply

Good test.

Lawrence.
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Old 9th Mar 2023, 9:00 am   #24
ToonMurphyB40
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Default Re: Question Murphy B40 Power Supply

The B.R.1617 manual specifies the range of 40Hz to 60Hz for the allowed B40 receiver mains frequency.
Due to the full-wave rectification for the HT-voltages, the ripple frequency is in the range of 80Hz - 120Hz.
My conclusion:
There is no reason to optimize the resonant filter components for the mains frequency range of 40Hz - 60Hz.The capacitors C316 // C317 comply for the mentioned mains frequency range.
The ‘ripple attenuation response slope’ is flat within 0.6 dB.

Toon. PE1NHP
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Old 9th Mar 2023, 10:58 am   #25
Andrew Sinclair
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Default Re: Question Murphy B40 Power Supply

This article from the IEE Electrical review Volume 108 Part A Number 37 February 1961. It explains the change of RN Ships mains from DC to 115V 60Hz AC.
The B40 receivers were used in shore stations as well as ships, so 240V 50Hz would have been a necessary requirement.
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Old 10th Mar 2023, 3:30 pm   #26
ToonMurphyB40
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Default Re: Question Murphy B40 Power Supply

Thanks for your interesting contribution Andrew.
60 Hz will now be the standard for ships.
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Old 10th Mar 2023, 10:02 pm   #27
CambridgeWorks
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Default Re: Question Murphy B40 Power Supply

Around 10 years ago, RN ship radios were still 115V 60Hz.
We just used 115V 50Hz when testing them.
Rob
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Old 11th Mar 2023, 11:52 am   #28
ToonMurphyB40
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Default Re: Question Murphy B40 Power Supply

Lawrence,
I enjoyed the beautiful picture you sent of your ‘radio table’.
The Murphy B40 has a nice place between the other ‘jewelry’….!!!
Toon
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Old 11th Mar 2023, 11:58 am   #29
ToonMurphyB40
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Default Re: Question Murphy B40 Power Supply

My ‘radio table’ ….
Best regards,
Toon
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Old 11th Mar 2023, 4:54 pm   #30
ToonMurphyB40
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Default Re: Question Murphy B40 Power Supply

That’s interesting Rob.
This means that the ‘Mains Voltage Selector’ on the back of the B40 receiver was actually used by Navy personnel!
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Old 11th Mar 2023, 5:39 pm   #31
ms660
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Default Re: Question Murphy B40 Power Supply

Quote:
Originally Posted by ToonMurphyB40 View Post
My ‘radio table’ ….
Best regards,
Toon
Very nice and looks strong too, I had an Eddystone receiver, a 358X, it had plugin coil packs, also had a Racal receiver.

Lawrence.
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