I was given a Toyota 2009 RAV4 from my sister who can no longer drive. I decided to install an old Kenwood radio that I had purchased years ago into that vehicle. The Kenwood TM-D710A radio is a dual display radio because two channels can be received. MSRP for the TM-D710A when it was sold $600. I have this model. E-Ham Score for TM-D710A: Average rating: 4.2/5
TM-D710A is no longer made.
Current, in production, model is TM-D710 GA, ($530 to $580). It includes a GPS (Global Position System) unit.
It also has a E-Ham average rating of: 4.2/5
Listed cost about $600.
Some terms that will be used:
• APRS Ready (I purchased a separate GPS unit for this radio) (I am using this) • APRS Weather Station ready
• KSS II+ (kenwood Skycommand II+)
• NMEA 0183 GPS I/O port
• Built-in 1200/9600 bps TNC (Packet) (Not using this) • Echolink Ready (Not using this)
• High RF Power Output (V/U: 50 watt)
• 1000 multifunction Memory Channels
• Dual Receive on same band (V+V, U+U)
• NOAA Weather Alert/RX (US Only)
• Voice Guidance & Storage option (VGS-1) This is installed.
• MCP Compatible with ARRL “TravelPlus”
• With “illegal” MARS / CAP Modification radio can transmit into FRS frequencies:
Cut one wire and remove one resistor is all that is required for this modification. At first I did not have the guts to make this modification. What changed my mind was when I shared this installation document to our local RACES group, a ham radio operator said he makes the MARS /CAP modification to all of his radios. This modification results in the radio violating the FCC rules set for FRS (Family Radio Service) hand held radios. BUT, in an emergency, all FCC rules are thrown out the window as they expect results for assisting aid, not compliance.
Diamond model NR770HNMO Average cost $60
E-Ham review score: Average rating: 3.4/5
2 meter and 440
No ground plane required
Gain: 3.0 on 2 meters and 5.5 db gain on 440. Connector: NMO
Diamond Deluxe Luggage Rack Mount model K515SNMO. Cost: $70.
SMA connector attached to coax. SMA to PL-259 included. Installation was very easy. The mount allows the antenna to stay mounted but can be angled forward or backward and also side to side. This allows the owner to angle the antenna horizontally so the vehicle can enter a garage without removing the antenna. The antenna lead-in cable has a very small diameter. I used split wrap to protect the antenna cable for the portion of the cable exposed outside the car. I purchases a NMO protector cap.
I used Split Wrap and applied it to the antenna line coming from antenna mount and as it enters the car door.
Image below shows Split Wrap being applied to antenna line coming from mount.
Power Supply line Installation:
• Power line was routed directly from the car battery through the car fire wall and into the passenger compartment with 12 gauge wire. It took about 3 hours to make a hole through an existing rubber gasket on the passenger side using a small diameter Phillips head screwdriver. (see image below). Anderson Power Poles were soldered to the wire ends inside the car cabin.
• Connections had to be made at the battery and an in line fuse was included to protect this wiring. I used split wrap to protect some of the power lines within the engine.
Image below shows split wrap being applied to main power from battery.
The disadvantage of supplying constant power to the radio from the battery, is you could run the car battery down if you forget to turn the radio off. I set the APO (Automatic Power Off) to 60 minutes, just in case I forget to shut the radio off when I leave the vehicle for a long time. The APO resets it’s timer every time you make any change to one of the radio controls.
• The main radio was mounted on a plastic sheet. Under that sheet I placed the hook side of Velcro. This Velcro attached itself to the car carpet under the passenger seat with such force that I had to almost use crow bars to lift the radio so I could service it.
• A method was needed to mount the radio control head. A cup holder was decided upon because there was no impact into the car like glue or drilling.
I purchased the Lido LM-802 Heavy Duty Cup Holder Mount. Cost $45.
The Toyota 2009 RAV4 has 2 cup holders between the driver and passenger. This cup holder installation naturally takes up one of those cup holders. This car has rubber inserts that can be removed to make for larger drinks. I found that the radio mount needed those rubber inserts. Also, the mount expands or contracts to the size of the cup holder by turning the large knob just above the portion that slips into the cup holder. I had to really expand the mount so it would not mover around. Note that the mount, seen above, has 2 rings toward the bottom The one on top gives you more expansion and one below for smaller expansion. I had to use the smaller expansion portion.
There is also a large knob that compresses two opposing ball joints at both ends of the top portion. This allows you to angle both the cup holder and the radio head mount. I found that I had to try to keep the holder in a vertical angle as much as I could so it would be less prone to dip.
The radio head has dual display. Left side is completely separate for reception and transmission and so is the right side. I chose to have APRS set for the right side of the control head. When working properly the top right of the display are the words “BCON GPS” The GPS must flash on and off to tell the operator that the GPS receiver component for APRS is working properly.
I also had to drill some holes into the adapter plate that comes with the cup holder mount so the radio head plate could be bolted to the cup holder plate. (see next image below). The cup holder plate allows for slide removal of radio head.
The Kenwood mounting plate allows the radio head to also easily be removed because it has 2 sections. One section stays attached to the radio head and the other is part of the mounting plate. A simple press to release uncouples the two. The Lido plate is bolted to the under side of the Kenwood plate.
• Audio Out Solutions
I found three solutions to providing audio out of the ham radio:
#1 The main radio has a single speaker that provides audio for both radio channels. But, because I put the main radio under the passenger seat, the audio favored the low frequencies.
#2 The automobile has an auxiliary audio input located in the console between the driver and passenger. The advantage for this method is the audio comes out toward the operator from the front of the car. The radio has 2 speaker outputs which were easy to wire into the Aux audio input. The left audio channel as seen in the radio display comes out of the left side car speakers. The right side of the radio display’s audio comes out of the right side of the car speakers. This audio has the best quality of the three solutions. I chose to put the APRS signal into the right channel and I turn that volume down because I do not want to hear the digital tones. In an emergency which includes CERT volunteers, I would shut off APRS on the right channel and switch to FRS. I like to keep the left channel for active RACES station traffic.
3. The third method was to mount 2 separate speakers to the driver’s seat headrest (see image below). The problem with this was the audio comes from behind the operator. When using APRS, the radio sends out tones which can not be turned off. The tones come out of both audio channels equally. Thus, those tones seem to come right behind the head of the operator. This audio solution takes some time to get used to it.
I swept the car antenna with a SWR meter and the results were near perfect for the whole 2 meter band. My meter, being very old, can not sweep 440.
The radio GPS (Global Positioning Unit) was a pain to keep working while I was setting up the radio. Every time I inputted a new list of frequencies stored in the radio, I lost GPS. I even had to do a radio factory reset. The number of menu items one needs to go through to make the GPS work, is over 15! Any one of those menu items being set incorrectly would take down the GPS. But, once I got the menu system set correctly, the unit worked perfectly.
I came to realize that putting this radio in this car really added to my capabilities for the city. Let me list the improvements that I can now provide:
- My connectivity and capacity to communicate has drastically improved. The range of this radio is 1 to 3 miles. The new car radio has 50 watts of RF power out when set to high power.
- My exact location is available. With the radio APRS capability, I can easily be found on a map in real time using APRS Google Maps. I can also use APRS to find another operator that is transmitting their location using the radio control head. APRS shows direction and distance between stations in the control head display.
When you get another ham radio operator to show up on the APRS display, it shows a compass heading for that station. If I press POS (Position) on the control head I see more information such as distance between me and the other station. The compass shows the direction. It is this feature that allows a radio operator to find and get near another station that is sending out APRS position signals.
Anyone can do a Google search for APRS and a map will appear. In the APRS image map, you can see APRS radios that have transmitted within the past hour within any zip code you specify. You can change the station logo image. WX stands for weather station. I chose car for my Toyota RAV4.
- I now can respond at any time to a call out. Before, I shared a car with my daughter.
- My vehicle can carry support items. I now can take with me food, clothing, sleeping bag, tent, cooking devices. My car can be used to make supply runs.
- If I make MARS / CAP Modification to the radio, I can transmit into FRS frequencies. FRS radios are really handicapped by extremely low power and not being able to switch antennas. FRS radios have an awful range. But, if I were to open my radio up to MARS /CAP modification, then my radio would have way better receive capability and fantastic transmit power. Our job as RACES members is to support CERT volunteers and if the only communications they are using is FRS then we need to be capable of reaching them. It is illegal to transmit on FRS frequencies with this high powered radio unless there is an emergency.
APRS Web Site: http://www.aprs.org/aprs.html
MARS /CAP Modification Reference: https://www.youtube.com/watch?v=zm-8vBU29pw