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## Pin 7 Current Capacity?

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• Does anyone know how much current can be passed through pin 7 of the radio connector on the tracker 2? Or more to the point, how about the trace on the PCB? My
Message 1 of 4 , Apr 4 8:57 AM
Does anyone know how much current can be passed through pin 7
of the radio connector on the tracker 2? Or more to the point,
how about the trace on the PCB? My HT draws about 550ma on tx,
and about 25 on squelched rx. I was hoping to do up a single
cable going from the Tracker to the HT.

Thanks, Rob..
• Rob, Scott is most likely on his way to Hong Kong and would have the best answer. I don t have my OT2M handy to look at the board, but as I remember the trace
Message 2 of 4 , Apr 5 2:03 PM
Rob,

Scott is most likely on his way to Hong Kong and would have the best answer. I don't have my OT2M handy to look at the board, but as I remember the trace is pretty wide, probably more than 15 mils, which should give you at least 1 amp for the low duty cycle. If you have a way to measure the trace width, here is a ball park calculator for determining current capacity of the trace:

http://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/

Use 1 oz per sq foot for the copper.

Larry
K7YBZ

--- In tracker2@yahoogroups.com, "ve7rwn" <neurob@...> wrote:
>
> Does anyone know how much current can be passed through pin 7
> of the radio connector on the tracker 2? Or more to the point,
> how about the trace on the PCB? My HT draws about 550ma on tx,
> and about 25 on squelched rx. I was hoping to do up a single
> cable going from the Tracker to the HT.
>
> Thanks, Rob..
>
• Considering the tracker s able to source a fair bit of 5v current to run a GPS, as well as itself when powering through pin 7, you should be fine going the
Message 3 of 4 , Apr 5 2:55 PM
Considering the tracker's able to source a fair bit of 5v current to run
a GPS, as well as itself when powering through pin 7, you should be fine
going the other way.... I haven't heard of anyone running it this way,
and don't recall Scott having weighed in on this previously, but with no
firm numbers or specs to confirm this, remember that TX power is a
second or two spike with the constant being 25ma (think about how low
the duty cycle is with a 2 sec transmit every couple mins... barely a
drop in the pond).. *shrug* If you're worried, you could always add a
cap inline to your radio to help give you the little extra current when
needed..

p

ve7rwn wrote:
> Does anyone know how much current can be passed through pin 7
> of the radio connector on the tracker 2? Or more to the point,
> how about the trace on the PCB? My HT draws about 550ma on tx,
> and about 25 on squelched rx. I was hoping to do up a single
> cable going from the Tracker to the HT.
>
> Thanks, Rob..
• I actually don t leave until Friday, but I m busy trying to get everything done before then. Trace width is 24 mils, length to the coaxial plug is around 3 ,
Message 4 of 4 , Apr 5 3:10 PM
I actually don't leave until Friday, but I'm busy trying to get
everything done before then.

Trace width is 24 mils, length to the coaxial plug is around 3", copper
thickness is 1 oz/sq ft. According to the calculator, it'll carry a 1
amp load continuously with a 15 degree C temperature rise. An HT
shouldn't be a problem.

Scott

k7ybz wrote:
>
>
> Rob,
>
> Scott is most likely on his way to Hong Kong and would have the best
> answer. I don't have my OT2M handy to look at the board, but as I
> remember the trace is pretty wide, probably more than 15 mils, which
> should give you at least 1 amp for the low duty cycle. If you have a way
> to measure the trace width, here is a ball park calculator for
> determining current capacity of the trace:
>
> http://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/
> <http://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/>
>
> Use 1 oz per sq foot for the copper.
>
> Larry
> K7YBZ
>
> --- In tracker2@yahoogroups.com <mailto:tracker2%40yahoogroups.com>,
> "ve7rwn" <neurob@...> wrote:
> >
> > Does anyone know how much current can be passed through pin 7
> > of the radio connector on the tracker 2? Or more to the point,
> > how about the trace on the PCB? My HT draws about 550ma on tx,
> > and about 25 on squelched rx. I was hoping to do up a single
> > cable going from the Tracker to the HT.
> >
> > Thanks, Rob..
> >
>
>
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