[time-nuts] Hand Held GPS

paul at greenrover.demon.co.uk paul at greenrover.demon.co.uk
Mon Mar 30 06:18:22 UTC 2009

bg at lysator.liu.se wrote:

> I would check the antenna types to be tested at home with a new Garmin to
> see if the antennas work with below spec DC voltage.

Hi Bjorn, thats a good suggestion and as a test I just tried my TomTom 
vehicle unit which supplies just fractionally over 3v at the antenna 
connector.  When attached to my two fixed antennas here, a Motorola and 
a Garmin, both 5V antennas worked fine.

I'll run up to a local site with a long feeder run and re test

 > Perhaps a bias-T and a small chargeable batterypack can give the right
 > antenna voltage?

That's also a good move and could also implement a little diagnostics 
capability by monitoring the volts/current, but if a standard gps will 
do the go /no go test its less to carry (and break) in the field.

Again, thanks.

73 de Paul GW8IZR IO73TI

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