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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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5th Oct 2015, 3:37 am | #1 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Marconi T.M.E. 20 B/I RF Bridge
Hi Gents,
I'm searching for some information about a Marconi T.M.E. 20 B/I RF Bridge Specs, description etc. Maybe someone know this beast ? Thanks Peter |
5th Oct 2015, 2:59 pm | #2 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Re: Marconi T.M.E. 20 B/I RF Bridge
Inside
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5th Oct 2015, 7:37 pm | #3 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Re: Marconi T.M.E. 20 B/I RF Bridge
Some more info:
Function switch - C - BAL / UN - L - BAL / UN Switches for C: 0 - 10 x 0.001 uF 0 - 10 nF 0 - 10 x 0.0001 uF 0 - 1000 pF 0 - 150 var. dial 0 - 0.0001 uF 0 - 100 pF Resistance, var.: Fine Resistance Balance Switches for R (mS): 0 - 10: x 100 mS 0 - 10: x 10 mS 0 - 10: x 1 mS 0 - 10: x 0.1 mS 0 - 10: x 0.01 mS 1 mS = 1 / 1000 Ohm on top: terminals for "X" DUT connectors from left to right zero ohms (Impedance ??) weight appr. 20 Kg How to use ? Peter |
5th Oct 2015, 7:47 pm | #4 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,902
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Re: Marconi T.M.E. 20 B/I RF Bridge
It looks like it needs a signal source and a detector as companion boxes.
Nicely made with some components similar to the Marconi "Circuit Magnification Meter" of the same period. David
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5th Oct 2015, 8:19 pm | #5 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Re: Marconi T.M.E. 20 B/I RF Bridge
Case looks like TF340 / TF517 etc
area appr. 1940 ?? TF1245 looks to new HP |
5th Oct 2015, 9:17 pm | #6 |
Octode
Join Date: Sep 2004
Location: St. Albans, Hertfordshire, UK.
Posts: 1,478
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Re: Marconi T.M.E. 20 B/I RF Bridge
I have a document that claims TME 20B/1 is part of "OA199A/2 RF Impedance Bridge Assembly" and can be found in the 1959 Marconi Instruments catalogue. Unfortunately I have no more info. than that. I will dig around a bit.
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Regards, Richard, BVWS member |
5th Oct 2015, 11:17 pm | #7 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Re: Marconi T.M.E. 20 B/I RF Bridge
Some specs would help ;-)
Peter |
6th Oct 2015, 10:01 am | #8 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
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Re: Marconi T.M.E. 20 B/I RF Bridge
Peter,
very interesting this early bridge. I turned up a research paper here:http://www.researchgate.net/publicat...om_Temperature which is dated 1968, and mentions the use of the bridge at 100kHz and 10MHz. For the range 10MHz to 1GHz they used a General Radio 1602B bridge, so that suggests your bridge is only rated to 10MHz. And looking at the internal construction with those large micamolds, that sounds about right. Of course the 1968 date is only the date of the research, and they would have used instruments they had to hand, which of course could easily be decades old even then. I suspect the 1940 date that someone else suggested is not far out. Richard |
6th Oct 2015, 4:11 pm | #9 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Re: Marconi T.M.E. 20 B/I RF Bridge
Richard,
didn't find your paper / no access ;-( But, I found a schematic from Bell Labs that shows there RF bridge prinzip, and lookes similary to the TME20, I think ? Peter |
10th Oct 2015, 6:04 pm | #10 |
Hexode
Join Date: Apr 2007
Location: Wiesbaden, Germany
Posts: 333
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Re: Marconi T.M.E. 20 B/I RF Bridge
I forgot to say (posting 3)
1 mS means 1 Milli Siemens (symbol S) is the unit of electric conductance, electric susceptance and electric admittance in the International System of Units (SI). |
11th Oct 2015, 9:23 am | #11 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: Marconi T.M.E. 20 B/I RF Bridge
The mho (inverse ohm) as was, no less.
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11th Oct 2015, 10:02 am | #12 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
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Re: Marconi T.M.E. 20 B/I RF Bridge
Peter,
to access the paper you have to click on "preview" quickly before it takes you to the login/register page. You can read the whole paper in preview mode anyway..... It doesn't actually tell you much though - since its not primarily about the bridge. There are many papers about bridges available. It doesn't describe your particular bridge, but there is a historical paper about impedance measurements with particular reference to the General Radio Company that can be downloaded from here. That paper goes into many types of bridges, and no doubt your bridge will fit one of them. Richard |