What is your DC power source? https://www.tapr.org/images/com-cbl.jpg I used pin 7 (Black, DC GND) and pin 8 (Red, +8 to +32 VDC) .... and old +12 VDC, 1 Amp Wall Wart for my build. greg w9gb Sent from iPad Air

Hi Greg, I'm using a 12 V 7 Ah gel cell for the power and have a small Trimble magnetic puck antenna connected just for testing. Chris > On Jun 14, 2017, at 1:22 PM, Gregory Beat <w9gb@icloud.com> wrote: > > What is your DC power source? > https://www.tapr.org/images/com-cbl.jpg > > I used pin 7 (Black, DC GND) and pin 8 (Red, +8 to +32 VDC) .... > and old +12 VDC, 1 Amp Wall Wart for my build. > > greg > w9gb > > Sent from iPad Air

Last night I measured the voltages on the serial lines with a DMM. The TXD coming from the GPS was a solid -5.9 V. The RxD was 0 V. Chris > On Jun 14, 2017, at 10:53 PM, Chris Waldrup <kd4pbj@gmail.com> wrote: > > Hi Greg, > > I'm using a 12 V 7 Ah gel cell for the power and have a small Trimble magnetic puck antenna connected just for testing. > > Chris > >> On Jun 14, 2017, at 1:22 PM, Gregory Beat <w9gb@icloud.com> wrote: >> >> What is your DC power source? >> https://www.tapr.org/images/com-cbl.jpg >> >> I used pin 7 (Black, DC GND) and pin 8 (Red, +8 to +32 VDC) .... >> and old +12 VDC, 1 Amp Wall Wart for my build. >> >> greg >> w9gb >> >> Sent from iPad Air