[Boatanchors] Speech Amp Again

[Carl]

Dreamer!

Carl


----- Original Message ----- 
From: "Bob Macklin" <macklinbob at msn.com>
To: "Carl" <km1h at jeremy.mv.com>; "rbethman" <rbethman at comcast.net>; 
"Barrie Smith" <barrie at centric.net>
Cc: <boatanchors at mailman.qth.net>
Sent: Wednesday, November 19, 2008 4:18 PM
Subject: Re: [Boatanchors] Speech Amp Again


>I hope the chassis of the two units are tied together with a 
>substantial
> bonding strap and the shield is not use to provide the ground between 
> the
> two units!
>
> Bob Macklin
> K5MYJ
> Kent (Seattle), Wa,
> "Real Radios Glow in the Dark"
>
> ----- Original Message ----- 
> From: "Carl" <km1h at jeremy.mv.com>
> To: "Bob Macklin" <macklinbob at msn.com>; "rbethman" 
> <rbethman at comcast.net>;
> "Barrie Smith" <barrie at centric.net>
> Cc: <boatanchors at mailman.qth.net>
> Sent: Wednesday, November 19, 2008 12:45 PM
> Subject: Re: [Boatanchors] Speech Amp Again
>
>
>>
>> ----- Original Message ----- 
>> From: "Bob Macklin" <macklinbob at msn.com>
>> To: "Carl" <km1h at jeremy.mv.com>; "rbethman" <rbethman at comcast.net>;
>> "Barrie Smith" <barrie at centric.net>
>> Cc: <boatanchors at mailman.qth.net>
>> Sent: Wednesday, November 19, 2008 2:59 PM
>> Subject: Re: [Boatanchors] Speech Amp Again
>>
>>
>> >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"
>>
>>
>> That only holds true on a battle ship where a real ground is 
>> established
>> (;
>>
>> In the typical ham shack its a crap shoot if there is any ground and 
>> the
>> only load is the one the ham has on....hic
>>
>> That was the reason for my suggesting trying different ends.
>>
>> Carl
>> KM1H
>>
>> >
>> > ----- 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
>> >> >
>> >> > _______________________________________________
>> >> >
>> >>
>> >> _______________________________________________
>> >>
>> >
>> >
>>
>>
>
>