Kenwood TM-D710A

Mobile rig

• Kenwood TM-D710A dual band radio
• Larsen 2/70 antenna with NMO base
• GPS - will use either Ublox Antaris 4 AEK-4P or Garmin Monterra in AMPS mount
• Flint Hills Radio Low Loss PowerGate 25AMP and
• 7AH SLA battery for back up power.

I have this alternative backup system too but at 10A it's not big enough.

• PowerStream battery 10A back up unit http://www.powerstream.com/DC-UPS-1212-10A.htm
• and Rigrunner with USB outlets

History

2015-Sep-19 Installed GPS in car, didn't have the manual w me so have not been able to test!

2015-Sep-xx Installed base and mic in Yaris, no longer bounces along on the floor behind seats. Radio is under cargo deck. Mic bracket is on center console.

2012-Nov-11 Terminated coax with crimp on PL-259 connector from Fry's

Transceiver goes behind driver seat.

NMO base with RG58U coax Coax is routed from the middle of the roof where I punched a hole to the rear of the car and down the left side c pillar under the trim panels and pops out from under the driver's side rear seat panel.

Routed a 10g pair of wires from the battery through a rubber plug on the firewall near the main ECU. Wire goes through console under carpet and pops out under where the rear seat would be. Seat was removed and stored away in the garage and replaced with a cargo deck.

There are fuses on each wire power and ground at the battery. The wires terminate in an Anderson Powerpole 45A connector.

== Connecting main unit and head

They provide a cable, but that's in the car now. What do I do when I want to bench test?

Head

• 3 encoders (2 are dual coaxial units) All three have buttons too.
• 13 push buttons
• LCD
• RJ45 connection to main unit
• 2.5 mm phone connector for GPS (really? phone for RS232)
• DIN connector for RS232 (really, how did they choose these connectors?)

• The main unit contains all of the RF section and the speaker and microphone
• The head unit is a user interface and also contains the TNC and APRS subsystems.
• The main unit is shared with another product, the TM-D71 I think.

The new version of the head unit has GPS built in.

What would I WANT the head unit to look like?

Hardware

• Daylight readable touch screen, about 5"
• The usual minimal Android buttons: power and up/down
• Generic USB ports, probably 4 ports; one is for GPS
• Bluetooth
  • Support for external bluetooth keyboard makes texting via APRS and PSK31 etc easy
  • Support for Android audio on car stereo (turn by turn directions for example)
  • Detect TX and mute Android audio and car stereo?
  • Since audio is in the main unit, can't pipe audio to a BT headset.
• Small built in speaker
• AMPS mounting holes
• Runs Android 4.4 Kitkat or better, upgradeable. http://bbbandroid.sourceforge.net/

Wish list

• TNC in software
• APRS as Android app
• Built in support for scanning repeaters in the area
• DMR support https://en.wikipedia.org/wiki/Digital_mobile_radio Note that DMR is a UHF thing
• Support WiFi via USB? Gateway to Echolink could be interesting
• Support GSM via USB or module? Gateway to SMS could be interesting

If I want to use an external laptop for any reason, I think the best way to connect would be via bluetooth, avoiding extra dangling wires and connectors on the head unit. But this thing is so easy to use that I can't see you'd want to use a laptop for much. Maybe to transfer logs and gps tracks?

It needs a network connection to allow for updates but I am loathe to build wifi into it, so I think plugging in an external WiFi stick as needed suffices.

KISS - no built in GSM no built-in GPS - external USB GPS mouse is cheap and lets you put the antenna where you want it

BeagleBone Black might be good for proof of concept, could be acceptable in finished product because I don't anticipate heavy media usage (playing games and movies not a good idea in car)

• dual core CPU
• 1g RAM
• can run Android
• has an ethernet port, so you could do updates over a wire.

some available relevant capes

• NimbeLink Skywire $104 (Digikey) adds cellular+gps+usb but costs too much