On Thursday 12 June 2003 18:36, Matt Pobursky scribbled:
> On Thu, 12 Jun 2003 22:46:19 +0100, Timothy Box wrote:
> > On a board I am doing I am restricted to where I can place the LCD
> > connector and a PCB mounted BNC aerial connector.
> >=20
> > The BNC has to over lay the lcd pin sockets. While it is not a
> > problem as the LCD is on 1 side and the BNC there might be a noise
> > issue.
> >=20
> > The obvious thing is grounding of the pins on the case of the BNC
> > which I know I have to resolve but the my main worry is noise getting
> > in on the RF signal. The two pins under the BNC are the backlight
> > which might be PWMed through a mosffet to control brightness.
> >=20
> > Any thoughts?
>
> If you are really stuck with the mechanical constraints you've shown,
> I'd consider a cable assembly between LCD module and PCB. You could
> either use a flat flex cable to relocate the PCB connection in the
> negative Y direction or use a discrete wire cable and locate the
> connector almost anywhere on your PCB you'd like.
>
> I normally don't like to do this (I'd rather use a solid mechanical
> connector system), but I have occasionally used a cable is situations
> like yours.
>
> I agree with the potential noise problems too. Unless you have the time
> and money to risk a second spin on the PCB, I think I'd relocate the
> LCD connection on the PCB.
>
> Matt Pobursky
> Maximum Performance Systems

Alternately, how about making a small carrier board for the BNC, and moun=
ting=20
that a 1/4" or so off the board?  Then groundplane or otherwise shield in=
=20
between.  The end result should be just as if you had a taller BNC connec=
tor. =20
Let the RF experts decide if this will make enough of a noise difference.

Cheers,
-Neil.

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