[Boatanchors] Speech Amp Again

[Bob Macklin]

A shielded twisted pair should have the shield only connected to ground at
one end so the shield does not carry current. It is most common to ground
the shield at the load end.

Bob Macklin
K5MYJ
Kent (Seattle), Wa,
"Real Radios Glow in the Dark"

----- Original Message ----- 
From: "Carl" <km1h at jeremy.mv.com>
To: "rbethman" <rbethman at comcast.net>; "Barrie Smith" <barrie at centric.net>
Cc: <boatanchors at mailman.qth.net>
Sent: Wednesday, November 19, 2008 11:53 AM
Subject: Re: [Boatanchors] Speech Amp Again


> Shielding may create a ground loop problem between units. If hum is a
> problem try the shielding with grounding at one end at a time and then
> both. As John said twisting is the most important step, as it cancels
> common mode problems.
>
> Im using twisted # 16 cloth covered wire (just like in the old days) to
> both of my modulator decks with no hum pickup.
>
> Carl
> KM1H
>
>
> ----- Original Message ----- 
> From: "rbethman" <rbethman at comcast.net>
> To: "Barrie Smith" <barrie at centric.net>
> Cc: <boatanchors at mailman.qth.net>
> Sent: Wednesday, November 19, 2008 2:04 PM
> Subject: Re: [Boatanchors] Speech Amp Again
>
>
> > Barrie,
> >
> > I DEFINITELY shield them.
> >
> > Bob - N0DGN
> >
> > Barrie Smith wrote:
> >> Good Day:
> >>
> >> Should the leads from the speech amplifier, or the matching
> >> transformer, to the input of the HT-4B be shielded?
> >>
> >> 73, Barrie, W7ALW
> >>
> >
> > -- 
> > Bob - NØDGN
> >
> > _______________________________________________
> >
>
> _______________________________________________
>