The jack shields should be only connected to the radio ground - at the
radio, as well as the jack common terminal - as shown in the trig
diagrams. The jack common terminal must not be grounded to any other
ground or a loop will result, with possible nasty effects. (if in my case
the jacks are mounted in a metal airframe, they must be isolated from the
airframe using insulating washers).
IMHO, YMMV, "works for me" :-)
Cheers,
Pete
On Wed, Oct 29, 2014 at 12:01 PM, Steven Pitt <steven.pitt2@ntlworld.com>
wrote:
> steven.pitt2@ntlworld.com>
>
> Ira/Ferg/Peter
> Your input came at just the moment I am rewiring my radio and transponder
> equipment for mode S and 8.33khz and I was reviewing my ground/earth
> installation.
> As a non aviation electrician I have always been confused by these
> concepts and the issue of earth loops so can I ask for clarification.
> Shielded wire for the mikes and phones are shown as connected in the Trig
> diagrams so that suggests to me that connecting them all together and then
> running one wire back to the battery negative contact would be the way to
> go.
> But then what about the ground strap to the engine block and the PTT wires
> which are shown as 'earthed'. How can you do that in a plastic aircraft.
> Sorry if this is really basic and although I have been flying for 8 years
> in 'DH I have always been uncertain that I had wired up the grounds
> correctly.
> Regards
> Steve
> ----- Original Message ----- From: "rampil" <ira.rampil@gmail.com>
> To: <europa-list@matronics.com>
> Sent: Tuesday, October 28, 2014 2:09 PM
> Subject: Europa-List: Re: Ground/earth
>
>
>>
>> Hi Ferg!
>>
>> Sorry, but there is no Ground but The Ground in a composite aircraft!
>>
>> That is to say, the negative side of the battery.
>>
>> From that it is simply a matter of practice in
>>>
>> minimizing the resistance back to that point. Noise is created when
>> changing current flows move across a resistance, and those changes
>> in current occur at high enough frequency to radiate to adjacent
>> conductors.
>>
>> Prevention of noise therefore seeks to minimize resistance to ground,
>> and improve shielding.
>>
>> Ira
>>
>> --------
>> Ira N224XS
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=432404#432404
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
|