Re: Grounding shematic for a Metal Chassis, which is the right way to wire up?


iz oos
 

Ok Tim, in that case the chassis of your rig is not connected to the chassis of the car. If bonded to the chassis of the rig and the negative of the battery one would create a ground loop. I think you connected directly the chassis of your radio to the negative of your battery with a wire of at least the same size of the 'red' cable.


Il 07/set/2018 20:49, "Tim Gorman" <tgorman2@...> ha scritto:
Respectfully, having fought noise problems in several different cars
and trucks, dependence on the dash to provide a ground or even
depending on the floor pan of the vehicle is a good way to introduce
noise into the rig. Not all body parts are properly connected together
and then connected to the battery and physical stress during car
movement can cause noise generation because of high resistance grounds.
Similar to single point grounds in places like telephone switches or
power substations, a negative lead from the radio directly to the
battery has always worked best for me.

tim ab0wr

On Fri, 7 Sep 2018 09:40:13 -0700
"iz oos" <and2oosiz2@...> wrote:

> Ok. Think to an audio amplifier in a car. Often you need just the red
> wire to turn it on. When the metal case of the amplifier is connected
> to the chassis of the car which in turn is connected to the negative
> of the battery (please correct me if I am wrong, I think it is
> correct). If you add another ground wire (the black in our example)
> is a nuisance that may make a ground loop. The same applies in the
> uBitx, if the case is all metal some wires are nuisances that may
> lead to ground loop issues.
>
> when use metal case then jack sleeves have ground at case an yellow
> wire isn't need any more and use thick black ground wire and and
> and..then big written 'be aware of ground loop
>
> Il 07/set/2018 17:50, "iz oos" <and2oosiz2@...> ha scritto:
>
> Not in Germany but not that far away, I have qsos on VHF with German
> stations only during contests with big big stations like DR9A... I
> mostly use qrp and minimal equipment on higher bands as well. Not
> every time an increase of noise level is due to ground loops. But it
> happened to me I solved noise issue using for instance isolating
> audio transformers between the rig and external accessories and
> especially PC soundcards. My case is all metal except for the front
> and the back panels so it is surely different from yours. I didn't
> notice annoying noise that could be due to ground loops. All
> installations are different. Ground loops may become a problem when
> too many things are connected together and are not bond together to a
> common ground point. I am not an expert on this, read the ARRL or
> equivalent handbooks that treat this topic.
>
> Il 07/set/2018 16:36, "sdr freak" <sdrfreak55@...> ha scritto:
>
> > ok thank you!
> >
> > would you life in germany, too? if yes, we should try to transmit
> > with the vhf radio when you want it too?
> >
> > ok by the way, in your post you mean the increased noise is a sign
> > of ground loops.. ok something new i have learned by this.. very
> > thankfully about these kind of knowledge!
> >
> > when the ground loops you say, isn't the problem in ubitx by wire
> > up the v1.9 shematic in a metal/aluminum case without extra ground
> > cable to the case and less cable for the sleeves, how i should i
> > understand the words in shematic v1.9 which says the things that
> > makes me crazy.. there is written when use metal case then jack
> > sleeves have ground at case an yellow wire isn't need any more and
> > use thick black ground wire and and and..then big written 'be aware
> > of ground loops'...
> >
> > this is the problem i doesn't understand and how have you make your
> > project by this, by the using of or not using these whole points
> > sayes in shematic v1.9? you dont have a metal box only front is
> > metal ?
> >
> > hm here again the shematic v1.9 which i have to understand..
> > https://groups.io/g/BITX20/photo/49276/0/uBITX_wireup_v1.9.
> > png?p=Name,,,20,1,0,0
> >
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