[Elecraft] So today i learned about BNC-BP and red/black terminals

[Henry Pollock - K4TMC]

Well...this has been an interesting revelation.  I just happened to have
two of those adapters, one with a female BNC and the other with a male BNC,
laying in my collection of adapters.  The one with the male BNC had the red
screw cap on the side with the tab and that side was electrically the
shield portion of the BNC connector.  The other adapter had the red cap on
the side that was electrically the center conductor of the BNC connector.
Although there were no manufacturing markings anywhere on the adapters,
physically the molded portions appeared to be identical, indicating that
potentially the same manufacturer made both parts.  Electrically, the two
parts were correct with only the screw cap colors reversed on one.  So,
maybe the final assembly person was color blind or 50% right was good
enough for their quality control department.

73,
Henry - K4TMC


On Mon, Aug 29, 2022 at 10:56 PM Marshall Harrison <marshall at gotspeech.net>
wrote:

> No, that is not a convention. They should follow the black is ground and
> red is hot but sometimes quality control isn't what it should be.
>
> I always check to make sure since the colored tops can be easily swapped so
> I don't trust them. The black/ground/shield side usually has a small tab or
> something to identify it  as being connected to the coax shield.
>
> *Marshall Harrison, *
> *W4MKH*
>
>
>
>
>
> On Mon, Aug 29, 2022 at 10:32 PM Bill Lederer <w8lvn.9 at gmail.com> wrote:
>
> > Team:
> >
> > I have been using a wire out the window from my upstairs office for an
> > antenna for my kx3. The wire goes to a tree about 30 feet away, so it is
> > essentially a random wire.  I have an additional wire that goes to a
> ground
> > rod one floor below.
> >
> > In doing some experiments with RBN and this combination with 5 watts, I
> was
> > confused about why connecting the wire to the tree to ground through the
> > BNC-BP and the ground wire to the hot side of the BNC-BP gave better
> > results.
> >
> > Finally, I measured which was which, and discovered that the black
> plastic
> > nut on this connector is actually connected to the center pin of the BNC,
> > with the red being ground. This was certainly contrary to my
> expectations.
> >
> > I also have a kx2 and got one of these connectors along with that kit.
> And
> > sure enough, it had the same convention--black is the center pin, red is
> > ground.
> >
> > This is contrary enough to my intuition that I reversed the nuts, so now
> > that the red indicates the center pin.
> >
> > Is this a convention that black is hot and red is ground with these?
> >
> > Thanks,
> > w8lvn
> >
> > --
> > --w8lvn--
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