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Sets, Parts and Service Information Offered (private sellers only, exact price required, no swaps) You may announce components or sets for sale or offered free here. Private collectors only - no traders. You must include an exact price. No swaps.

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Old 28th Feb 2020, 12:22 pm   #1
Downwind27
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Default Trompeter Concentric Twinax Connector

Sorry about the title.
I have some rather special connectors which I thought were BNC but they turn out to be something very different. Searching the Interweb shows several listings in the 20 - 30 mark. If this is any use to anyone it's yours for 3 including postage.

Does anyone know where these are used? I have more if you need them.
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Old 28th Feb 2020, 12:52 pm   #2
G6Tanuki
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Default Re: Trompeter Concentric Twinax Connector

That brings back memories - they were double-screened and used on medical/nuclear-instrumentation gear back in the 80s, along with the equally-expensive LEMO connectors.

Harwell/Daresbury Labs/Capenhurst used them in their thousands.
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Old 28th Feb 2020, 2:47 pm   #3
Radio Wrangler
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Default Re: Trompeter Concentric Twinax Connector

Also used to link RF signals between the boxes of the HP 3724A/3725A baseband analyser. Useful whenever you needed a double-sceened coax connection.

They are NOT twinax. twinax is a twisted pair inside a screen, and has a BNC-like connector with two pin connections. Twinax is a screened, balanced-pair

These are a single unbalanced signal connextion within a coaxial shield, with a second, insulated shield around that. Usually called TRIAX

Interesting history, but you're unlikely to come across anything using them, though anyone needing one will probably be desperate.

David
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Old 28th Feb 2020, 3:15 pm   #4
Malcolm G6ANZ
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Default Re: Trompeter Concentric Twinax Connector

Yes Triax connectors. Not easy to assemble though, the first one I had to make off took me about an hour. I can now do pone in 20 mins.
They are used with ion chambers and electrometers. The outer screen is ground, the next screen carries the -300v chamber bias supply and the signal is on the centre conductor. The inner screen usually has a semiconducting layer to reduce any noise.

Malcolm
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Old 28th Feb 2020, 4:36 pm   #5
John10b
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Default Re: Trompeter Concentric Twinax Connector

They also bring back memories to me, we used them extensively in the Instrumentation Department.
John
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Old 28th Feb 2020, 11:54 pm   #6
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Default Re: Trompeter Concentric Twinax Connector

Yes please, perfect for use with a Keithley precision voltage source that has these on the output.
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Old 29th Feb 2020, 4:57 am   #7
Radio Wrangler
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Default Re: Trompeter Concentric Twinax Connector

Mods.. might be worth changing the title from Twinax to Triax in case someone searching in posterity wants to find a thread on them.

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Old 29th Feb 2020, 5:08 am   #8
Radio1950
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Default Re: Trompeter Concentric Twinax Connector

Quote:
Originally Posted by Radio Wrangler View Post
Mods.. might be worth changing the title from Twinax to Triax in case someone searching in posterity wants to find a thread on them.
Except that the manufacturer calls them "Twinax".
Maybe leave that title alone; a search engine will find both words in this forum.

In Australia "Twinax" was a balanced 90 ohm cable and using PL259/SO239 type two pin connectors made by Acme.
Used in balanced HF RX antennas.
If I find one here I will post a piccie.
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