[aprssig] Suggestions for Automatic Power Off/Power On circuit for mobile rigs?

Keith - VE7GDH ve7gdh at rac.ca
Tue Nov 15 20:10:53 CST 2005

Jim KB0THN wrote on Nov 15 2005

> I've used small reed relay that sucks power from the Kenwood
> TM-D700 microphone connector to power the GPS on and off.
> That way the GPS is on when the radio is on only. On the
> Kenwoods there is 8 volts @ ~100mA on the microphone
> RJ-45 connector.

There is supposed to be ~100 mA available on the D700 mic connector,
but my brother had trouble with one of the keyboard interfaces from
John W2FS at www.coastalchipworks.com. Apparently most people can
get enough current from the D700 to run the keyboard interface and a
keyboard, but my brother's D700 wouldn't put out the current. On his
D700, the voltage was down to 5.57 volts with a 50 mA load on it. The
following was a load test putting various resistors across the "8
Volts" from the D700.

Ohms    Volts    mA
47         4.15    82.4
108       5.57    50
204       6.21    29.87
324       6.59    20
464       6.8      14.5
1009     7.1        7.03

73 es cul - Keith VE7GDH
"I may be lost, but I know exactly where I am!"

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