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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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4th Jul 2017, 3:30 pm | #1 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,996
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Harry S Truman radio.
Can anyone ID the radio shown in this photo:
https://static01.nyt.com/images/2015...-master675.jpg of Harry S Truman in his office during WWII. The style of some of the knobs is the pretty much the same as those used on the AR88. |
4th Jul 2017, 3:49 pm | #2 |
Octode
Join Date: Oct 2008
Location: Littlehampton, West Sussex, UK.
Posts: 1,465
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Re: Harry S Truman radio.
Except for the magic eye it looks similar to a Collins 75A1.
Jim |
4th Jul 2017, 3:49 pm | #3 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
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Re: Harry S Truman radio.
That appears to be a cabin on a ship.
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4th Jul 2017, 4:15 pm | #4 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Harry S Truman radio.
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4th Jul 2017, 4:23 pm | #5 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,996
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Re: Harry S Truman radio.
Indeed it is: It's from an article here: https://www.nytimes.com/2015/08/09/w...consensus.html
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4th Jul 2017, 4:23 pm | #6 |
Moderator
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Re: Harry S Truman radio.
There's another picture around showing a Hallicrafters SX28 in the oval office.
https://en.wikipedia.org/wiki/Hallic...umanOffice.jpg
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
4th Jul 2017, 4:24 pm | #7 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,996
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Re: Harry S Truman radio.
Does indeed look like it. Thanks!
Seems the RBO was a "Cabin receiver" though quite a bit better-specified than similar 'cabin receivers' produced in the UK by the likes of Eddystone. https://maritime.org/tech/radiocat/rbo.htm |
6th Jul 2017, 2:36 pm | #8 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,394
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Re: Harry S Truman radio.
The Scott receivers are an interesting breed- early in the war there was a degree of paranoia about stray radiation from shipboard receivers and they went to town on suppressing it with the use of isolating couplings between antenna and RF/mixer sections of the variable capacitor, ditto with bandchange shafts and keeping the aerial coil box isolated from but single-point-commoned with the chassis, all in the interest of restricting circulating currents and common impedances that could result in oscillator radiation from the aerial. One theme adopted in some versions was a grid-cap pentode RF amp (6K7) mounted between adjacent coil-box shielding plates in a manner reminiscent of disc-seal UHF triode practice, again ensuring that only the grid connection was inside the aerial box screen for minimum reverse coupling.
A great deal was made of the radiation suppression features in contemporary adverts, but I suspect that a more prosaic reason for this was to minimise interference to nearby RF devices on the same vessel, where both installations and aerials were cheek-by-jowl with each other, rather than the caricature images of fiends in U-boats cunningly taking DF readings. The Scott broadcast receivers could be described as resembling "upper middle class" consumer sets rather than full communications receivers in circuit topology, typically with 1 RF and 2 IF stages but fixed bandwidth and only some versions had a BFO. Nonetheless, the sturdy construction and attention to screening probably meant that they cost the US taxpayer a fair bit. The attention to low oscillator radiation was followed by many other professional receiver makers subsequently- the Pye CAT here is very much an "also ran" of a comms receiver but the aerial coil-box is carefully isolated from chassis by an assortment of Paxolin bushes and strips, the variable capacitor has a ceramic shaft with isolated earthing straps for the aerial section, the band-change shaft is made of Paxolin and broad slots are cut in the chassis around this coil-box, all showing the desire to keep stray coupling at bay. http://www.imradioha.org/scott_labs.htm Last edited by turretslug; 6th Jul 2017 at 3:02 pm. |
9th Jul 2017, 5:07 am | #9 |
Tetrode
Join Date: Aug 2013
Location: Monterey, California USA
Posts: 51
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Re: Harry S Truman radio.
The Scott receivers are very well made with high quality components and robust construction. Unlike the RMCA AR-8506B "Liberty Ship" receivers of the same era which were rather ghastly in terms of cheap, flimsy components and steel chassis panels.
The Scotts are AC-DC transformerless types intended as shipboard entertainment sets, although one model would fit in the receiver slot of a Liberty Ship radio room console and some were used that way. There is anecdotal evidence that after the war, Scott sold excess undelivered inventory in radio shops across the USA as a consumer short-wave receiver. |