Click to download the installation instructions

The GPS-710 is a custom built, uncluttered, plug-and-play solution for adding a stand-alone GPS to your Kenwood TM-D710 or RC710 radios. It uses a top-notch 20 channel SiRF-III GPS chipset (with WAAS, ENGOS, and MSAS augmentation) that can acquire GPS lock from a cold start in well under 60 seconds. The active internal antenna has proven itself in prototyping and beta testing to maintain GPS lock, even in very unfavorable placements. The GPS-710 pulls about 40mA of power from the line, and while this peripheral hasn't been approved by Kenwood, it should be well within the operational limits of the TX/RX Base.

As you can see from the photo below, the GPS-710 is hidden well behind the Operation Panel. The GPS-710 is attached to the Operation Panel with very high bond adhesive tape, designed to maintain a strong bond in temperatures up to 200F, which is well above the operating temperature limits of the radio. For anyone not wanting to mount the GPS-710 to the back of the Operation Panel, optional separation kits (6" and 24") are available.

The shielded serial jumper is manufactured using injection molded right-angle connectors with a strain relief. The data jumper uses a triple shielded cable that follows (and improves upon) the Kenwood design for shielding the conductors. The wires are cemented into the RJ-45 (CAT6) connectors before being bent and crimped into place. The resulting connection is extremely reliable; well beyond the Kenwood cable design. Each and every cable is individually tested before shipment.

The GPS-710 is FCC Class B certified, tested as a peripheral device to the TM-D710/RC-710. The RJ-45 jacks on the GPS-710 employ high quality EMI filters, so no additional ferrites should be needed on the cables.

The RJ-45 jack on the side with the GPS-710 label is for the cable that comes from the RF Base unit. This is what provides power to the GPS-710 and the Operation Panel. The RJ-45 jack on the opposite side connects, via a short jumper, to the Operation Panel... essentially completing the connection between the base and the panel.

On the TM-D700, the GPS connection went into the RF Base, but on the TM-D710, the GPS connection goes into the Operation Panel. The small 2.5mm socket on the unlabeled side of the GPS-710 connects, via short jumper, to the GPS input port on the side of the Operation Panel. The other 2.5mm socket (on the labeled side) is a pass-through port that allows for other device(s) to be connected to the two serial outputs. One serial output is sourced by the TM-D710 (waypoint output) and the other output is the GPS's NMEA serial output. Both streams are read-only.

I was originally planning on selling a USB cable that would connect the two streams into a laptop for use with UIView32, but the GPS-710 project is keeping me busy enough. It's pretty easy to connect the 2.5mm plug into an off-the-shelf dual RS232-to-USB device... but I don't have the time to manufacture them.  Two that I like in particular is the USBGear USBG-2XP2 and USBG-232FT-1 which can be taken apart so that the 2.5mm cable can be soldered internally.  This leaves the two DB9 ports available for something else (firmware programming, TNC, etc).  Note, while using the DB9 serial ports, you need to disconnect the 2.5mm cable from the GPS-710.

The mounting bracket and COM port are both completely usable with the GPS-710 installed.