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


Tim Gorman
 

Yep! That's the whole point of a single point ground! Run the negative
lead from the radio to the battery!

tim ab0wr

On Fri, 7 Sep 2018 12:44:35 -0700
"iz oos" <and2oosiz2@gmail.com> wrote:

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@cox.net> 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@gmail.com> 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@gmail.com> 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@gmail.com> 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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