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 Post subject: Shielded Twin Banana to BNC Adapter
PostPosted: Aug Tue 05, 2014 5:44 am 
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Joined: Jan Thu 24, 2013 4:55 am
Posts: 1253
Location: South New Jersey 08077
I wanted a shielded adapter to accept a 3/4" spaced twin-banana plug and connect to a BNC connector.
The key is a coax UHF-Female to BNC-Male adapter. To this is added a hand-made mounting plate and a grounding banana socket bushing; (solid metal, no insulator at all).
The first photo is the professional GR connector version, but not fully shielded at the binding posts:
Attachment:
File comment: GR adapter
BanannaX2_q1Hw.jpg
BanannaX2_q1Hw.jpg [ 6.71 KiB | Viewed 1450 times ]

The banana plug fits the center female contact of the UHF connector very nicely.
Here is what I built, with a dual-banana plug shown for scale:
Attachment:
File comment: Assembled Adapter and Plug
BNC-BananaX2_0804142347S.jpg
BNC-BananaX2_0804142347S.jpg [ 52.1 KiB | Viewed 1450 times ]

In the exploded view it is shown that the mounting plate has a large hole drilled and filed for the UHF connector, and has the grounding banana bushing spaced on 0.75 inch centers, a pair of mounting nuts for the UHF-Female secures the plate. If you don't have a bushing like that in the junkbox, the type of banana socket that used nuts and plastic shoulder washers for insulation could be used without its insulators.
Attachment:
File comment: Exploded view
BNC-BananaExploded-0804142352S.jpg
BNC-BananaExploded-0804142352S.jpg [ 29.98 KiB | Viewed 1450 times ]

Here the banana grounding bushing is seen sideways on the mounting plate (just a small scrap of aluminum sheet).
Attachment:
Detail-0804142354S.jpg
Detail-0804142354S.jpg [ 29.81 KiB | Viewed 1450 times ]

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 Post subject: Re: Shielded Twin Banana to BNC Adapter
PostPosted: Aug Tue 05, 2014 1:26 pm 
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Joined: Feb Sun 02, 2014 9:13 pm
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Location: Roanoke, VA
The GR adaptor in your first photo (apparently a Type 874-Q2) is designed to mate with a Type 874-ND to provide a well-shielded connection:

Image

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