[aprssig] info for TM-D710E in car

Dave Baxter dave at emv.co.uk
Wed Jan 23 04:24:02 EST 2008

The following device IS the solution to the problem stated by IK1AQI and
IZ1CQY :	 

Nope, that is NOT the solution to the radio loosing it's settings and
not updating it's postion data from the GPS, after a power dip during
engine cranking.

That device will however as it says prevent the main battery from being
emptied if an accessory (that is powered via it) is left on while the
engine is not running.   That is not the issue here.  That is that the
D710 locks up when the "12V" input drops below 11.45V.

They are asking if this has been seen by others, and if there are plans
for an updated (or modified) D710 that does not suffer in that way...
I suspect there are cascaded regulators used, 12V>8V then 8V>5V etc, so
when the first drops out, they all do.
IK1AQI and IZ1CQY also state they had found a temporary solution, by the
sound of it a 12V UPS of sorts (an extra battery in paralel with the

But you have to wonder about the mentality of a maker who produces a
piece of kit that if not specificaly designed for vehicle use, will be
used by many in vehicles, that does not tolerate, or behave sensibly
when the power momentarily dip's below a certain value.  There again,
that's nothing new, is it.

If you use a D710 (or anthing else that will be "P'd" off if the 12V
blips)  Best engineer some sort of 13.8V UPS.  Power Stream
(http://www.powerstream.com/) used to do such a module, but looking at
their website now, it's not listed any more.  But if cost is not an
issue, they do lots of stuff that you could use do make such a thing. A
High Power DC-DC converter, float charging a second battery for example.
The DC-DC converter/charger would only be enabled when the engine was
running and the generator working.

Or much cheaper, just use a "Split Charge" system with two batteries,
and use the second battery for the APRS kit.

Or one of Power Stream's regulating BuckBoost converters to keep a clean
DC voltage from the rather variable vehicle supply.   But that might
have spurious and QRM issues of course.

Cheers All.

Dave G0WBX.


	From: Terry Palmer [mailto:terrypalmer2 at compuserve.com] 
	Sent: Tuesday, January 22, 2008 10:21 AM
	To: TAPR APRS Mailing List
	Subject: Re: [aprssig] info for TM-D710E in car
	The following device IS the solution to the problem stated by
	I use this on a car with 12 volt accessories powered up 24/7 and
on a car with the ignition that powers up, then off, then on that above
authors mentioned.
	I leave the D700 turned on 24/7 and never have to use the
hardware power-on button; the d700 automatically turns on when the dc
voltage hits 14.1 and in the case of the car (Audi) that has accessories
hot 24/7, I have the APO3 set to turn off D700 after 10 minutes.
	You will love this device.
	P.S. I do not work for the company; just a satisfied customer.
	Terry K1LCH

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