Specifications

Digi m10 Hardware Reference v 1.20:

Page 27 of 36

6. Antenna Information

1. Which antenna should be used with the Digi m10?

Please refer to ORBCOMM Application Note #12, which can be downloaded from

http://www.orbcomm.com/equipment/pdf/App_Note_12__ORBCOMM_Antennas.pdf. It provides details

and comparisons of antennas from different vendors.

2. If the antenna cable is not long enough to reach my installation, how do I pick a suitable RF cable

to each it?

You can use any 50 Ω impedance, RF coax cable, provided the overall loss from the antenna to the Digi

m10 is less than 3 dB at 150 MHz. The lower the cable loss, the costlier the cable, so there is a trade off

between price and performance. LMR-400 would be an ideal choice for a 100 feet long cable. LMR-195 is

an excellent choice for shorter lengths.

3. What should I consider when I mount my antenna?

The antenna should be kept away from metal objects and the objects should not be parallel to the

antenna, as this will degrade the performance of the antenna. If a VSWR meter is available, measure the

VSWR of the antenna at 137.5 MHz and 149 MHz. A VSWR reading below 2 is required for good

performance from the antenna.