V-Strom 650
Motorcycle Mobile

That's me on my new motorcycle, a 2004 Suzuki V-Strom 650 (sometimes known as a DL650).  As if ham radio wasn't an expensive enough hobby, I had to start a new one last year.

Of course, I had to install as many electronic gadgets on it as I could.

On the left is the control head for a Kenwood TM-G707A VHF/UHF transceiver, on the right is a Garmin Quest GPS receiver with voice routing.  The accessory shelf was designed by Ray Fagan and is available through California Sport Touring.

While I started with the original Garmin suction-cup mount and modified it for motorcycle use, the management of the external audio amplifier that the Quest requires was a problem in the motorcycle environment -- It was always getting loose inside the cowling or getting in the way of other equipment.  With the introduction from Garmin of a mount specifically for motorcycles, it made sense to upgrade.  Garmin integrated the amplifier into the mount and did away with the "bridge" amplifier design that causes problems with grounded audio systems.  A piece of 1/8x2-inch aluminum L-stock provides a solid connection between Garmin's mount and the shelf..  Stuck to the back of the L-stock is a isolation filter which I added to break up the ground loop between the Quest and the AmpliRider which was introducing noise into the system.

The Kenwood G707 main unit fits under the Strom's seat:

Let me give you a quick tour from front to back (bottom to top of the picture):

Just in front of the storage box, you can see the 6-circut auxiliary fuse block which takes mini ATM fuses.  To its left, stuck to the edge of the box with mounting tape, is a relay activated by the ignition switch which allows half of those circuits to be switched, the other half un-switched. There is also a ground terminal strip just out of the picture below the relay.  The radio is on an un-switched circuit so I can use it when I'm parked, but I've added a timer in line with the power that cuts out an hour after the engine is switched off to prevent the radio and amplifier from running the battery down.

Just inside the storage box is a blue box which contains interconnects between the radio and the helmet wiring.  I started with a Motocom helmet setup for Kenwood radios, but I didn't like any of the transducers and ended up replacing just about everything except the wire and the connectors -- More on that later.  The box also has a 3v regulator to provide power for the electret microphone.

Behind (above) the blue box is the TM-G707A main unit.  The transmitter puts out 50W on 2M, and 35W on 440.  I chose the G707 because the microphone connection was in the main unit instead of the control head, and the controls are relatively simple and have a large, readable display.  You don't have a whole lot of ability to manipulate radio controls while riding a motorcycle (and wearing protective gloves).  It can also be modified fairly easily to operate on FRS and GMRS channels, which are used a lot in bike-to-bike communications.  I didn't do anything to permanently mount the Kenwood, it is just wedged under the seat support and padded with some foam rubber.  Where can it go?

Running over the radio is the seat support and latch.  Behind that, with the blue and green plugs going into it, is the AmpliRider audio mixer/amplifier.  This takes audio from the Kenwood, the Garmin Quest, and one other input (usually for my iPod) and mixes them together to drive the helmet speakers.  The volume control is remote and mounted on the handlebars

I transplanted the volume control from the box it was originally in to this short piece of PVC pipe.  The pipe end was notched with a barrel sander on a Dremel tool to fit the rear view mirror stalk and is held there with a tie-wrap.  The pipe gives a home for the push-to-talk button that comes with the Motocom set.

The Motocomm helmet communications system turned out to be inadequate for a number of reasons.  First of all, the speakers that they used could handle very little power, not anywhere near enough to make listening possible in the noisy environment of a motorcycle at speed.  I had a pair of Sony hi-fi headphones whose ear pads had disintigrated, and I disassembled them and used the transducers to replace the Motocomm speakers.  Helmet speakers can never produce the bass of headphones because there isn't good enough acoustic coupling to your ears, but the Sony transducers were infinitely better than the Motocomms.

Next to go was the microphone.  I think it is bordering on criminal to sell a microphone for motorcycle use that isn't noise-cancelling, but that's what Motocomm did.  A search of my junk box yielded a small noise-cancelling electret mic on a light boom that matched the electrical requirements of the radio and that I could wedge into the helmet's padding.

The resulting setup with the AmpliRider puts out just enough audio to be useable at highway speeds with earplugs in, and I have been able to carry on conversations with hams at speeds up to 80MPH (with a bit of difficulty).  It is certainly adequate for listening to music on my commute to and from work over surface streets.

My first antenna mount was a Diamond K540KM mirror/luggage rack mount clamped to the Hepco Becker saddlebag racks.  Recently I started doing bicycle events where an APRS tracker was highly recommended, which required a second antenna -- something the K540KM wasn't able to accomodate very well due to the asymmetrical racks.  With the help of a friend's machine shop, I was able to produce this replacement mount that bolts between the rear deck and the mount points for the saddlebag racks.

The material is 3/8-inch 6061-T6 aluminum about 1-1/4-inch wide and 24-inches long.  The tricky part was compensating for the fact that the mount point under the rear deck sloped forwards a few degrees.  I certainly didn't want my antennas pointing forwards, so I milled a 6-degree backwards slope into the ends to compensate.

The antennas are spaced far enough apart that they will just clear the top box when it is installed, but they only add about an inch to the width of the bike.  They are Diamond NR770HBs, 1/2-wave on 2M and 2x 5/8-wave on 440.  You want a 1/2-wave design on motorcycles because they don't have enough ground plane to support other vertical configurations.  Not shown are the clamp-on ferrite beads on the feedlines to keep RF out of the bike's electrics, and also to keep ignition noise from the frame from riding the feedline braid into the radio.

The APRS tracker is a stand-alone box bungied to the rear deck or pillion whenever needed.  Inside the water-resistant box is a Deluo GPS receiver, a TinyTrak3, a 2.5-watt IC-2AT, and a 2700mah 9.6V battery pack.  The TinyTrak controls an FET power switch for the Icom so that it is only powered-up a few seconds before the transmission of the beacon.  Battery life should be about 36 hours of continuous operation, and the pack can be recharged from 12V while the tracker is running.  The 3-position power switch is a locking type so that it can't shift during the ride, and can switch between the two sets of APRS parameters in the TinyTrak.  Screw studs for the TinyTrak's 9-pin D connectors had to be added to keep the connectors from vibrating loose on rough roads.