HAM Radio Install

Kenwood TM-V7A

David Sawyer




The Kenwood TM-7A and the Finished Interface

Roger W1RDR and his beautiful bride Sharon.

Major thanks go to Roger for the loan of his time, expertise and his radio and big hugs and thanks go to his wife for putting up with me and taking Roger away from her for a few days. I simply cannot put into words the gratitude I have for these 2 people and the enjoyment of friendship we have developed.

It took allot of years and some coaxing by my friend Roger but I finally got up the nerve to take the FCC HAM Radio License Test. I passed and am now a full fledged, legal, licensed Technician Class Ham Radio Operator KG6FNH. Combining that enjoyment with Motorcycling seemed only logical. Roger, W1RDR, already had a HAM radio rig on his Goldwing and was using 2 helmet headsets with 2 cords. He was already in the design and build process of a fully integrated wing interface but unfortunately priorities had forced it down on the list of tasks to complete. Once I got licensed Roger and I (well mostly Roger) set out to finish this project and use my bike, as the R&D model and me. The interface was actually 90 to 95% complete already and simply needed some additional wiring and then actual testing. It should be noted that this entire project is an accumulation of ideas and samples from other people. Don Webber KA7QQV was a major contributor both in the design and in obtaining some of the needed parts. There are probably other sources that only Roger knows about but suffice it to say that lots of people, whether they knew it or not, had a hand in the project. It should also be noted that this is a living project, ever changing, ever improving, ever tweaking. As changes come up I will make additional notation here and post any new drawings.

Roger took his hand drawn schematics and drawings on the various napkins and scraps of paper and sat down and put it on the computer. Once complete I was able to take those and wire up the rest of the various cables needed for the project. So far, here is a laundry list of items you will need:

For the Interface

Project Box

Project Breadboard about 4"x6"

Female 8 pin surface mount DIN

Female 5 pin surface mount DIN

Male 5 pin DIN

Male 8 pin DIN

CAT 5 cable, about 3 feet should be more then enough. Network cable with an RJ45 works great.

2 each 1-1 Transformer

1 each High/Low Matching transformer. (The quality of the entire project revolves around the quality on these transformers)

2 Capacitors 0.1 uf

3ea 20 K variable resistors (The schematic shows 10K and that will work but 20 K may give you better tuning performance)

1 each 180 Ohm 10% fixed resistor.

1 each 2.7k 10% fixed resistor.

1 each 670 ohm 10% fixed resistor.

Molex plugs to handle 13 pins

2 Female RCA type connectors

2 Male RCA type connectors

Different colors of single strand small wire for jumpers on the board.

 Additionally to make a relay for the PTT you will need:

Small Project Box

Small Project Breadboard (The size of the box and breadboard will be based on the size of the relay)

1 SPDP switch

1 N/C relay

1 Female RCA connector

1 Male RCA connector

 Tools Needed:

Project Vise or PCB Vise

Pen Tip Soldering Iron

Pump style Solder Sucker

Needle Nose pliers

Wire Strippers

Small Phillips and Flat Blade screwdrivers

Magnifying Glass (especially if you're old like me)

 So. On with the project:


Interface Schematic

This is the schematic. You will see that this is set up for Microphone, Audio and a Radar Detector.

The finished board will look something like this:

Completed Board

 The board shown above, while it is the same board Roger started with, he and I pretty much rebuilt it 2 or 3 times fixing problems. Once you assemble your parts I recommend that you start with one piece of the project at a time. You may want to start with the Audio piece first. Build that on the board, test it, and then go on to the Microphone side and then the Radar Detector. I did mention this also has a radar detector interface didn't I?

Once you get the board built you will need to make your cables. The following is the layout for the cables that you will need:

Audio Interface "Y" Cable

I did not use a Y cable with mine. I wired it direct. I thought it would make for a cleaner unit.


Interface Audio Cable

This is the cable that will connect the surface mount 5 pin DIN to the PCB connections via the Molex plugs.

Kenwood Interface Cable

This is the cable that has the Male 8 pin DIN and the RJ45 connector. The RJ45 will connect to the extender cable from the Kenwood Extender kit.

The RJ45 to Kenwood pin outs


The Kenwood owners manual has the pin outs incorrect. The above shows the correct schematic.


Audio Interface PCB Connections

This is the pin out that connects all of the cabling into the box. This is the molex connector pins.


PTT (Push To Talk) Relay

I did something unique here. I am using the Goldwings existing CB Radio PTT switch. By making this relay I am able to switch from the PTT for CB to PTT for HAM. This, to me, is better because it is actually less stuff to hang off the handlebars, is more integrated into the wing and the placement of the existing PTT is the best place of all.

PTT Relay

To start your project you will need to know how to solder, read schematics and have patience. A good quality soldering iron and a solder sucker is imperative. Plan on making mistakes and having to un-solder wires or components. I never liked the solder wick because to me it places too much heat on the board. Get yourself a decent solder sucker. You should also get a small project vise and or breadboard vise to hole the PCB in while you solder.

 This web page will not go into detail on building the actual interface but rather give you a shopping list, diagrams, photos and descriptions of the unit.


The completed box was placed under the left fairing pocket with the CellSet and the Nokia Car Kit module. I had to move my CD Player interface box from the left to the right side to make room. I mounted the PTT Relay box under the right side fairing pocket.

The PTT relay uses a relay to control the on-off capability of the PTT function. The Goldwing PTT uses a ground activation to activate the PTT. I cut the White/Grey Dot wire (pin 3) on the harness to the CB radio. You can verify that you have the correct wire by placing a VOM meter lead on pin 3 and the other VOM lead to ground. When you press the PTT you should get a reading. I placed the end going to the radio on the center pole of the SPDT and the side to the rest of the harness was attached to the bottom lug of the SPDT. When the PTT is depressed it closes a circuit to ground. For the HAM I placed the + (positive) side of the relay coil to my fused power distribution block and the ground side of the coil to the upper lug of the PTT. When the switch, mounted on my cigarette lighter box, is put in the HAM position then pressing the PTT completes the circuit to ground and activates the relay that closes the circuit for the HAM PTT.


 Disassemble and Assembled PTT Relay

The PTT Relay was a very easy item of this project to make. You take a small relay, I used a small one from Radio Shack, mount it on a small project board and solder 4 wire connections. Size of this box is determined by the size of the relay you get. You could, if you desired, use a slightly larger board for the interface and actually have this piece right on that same interface PCB. Since this PTT idea came up after the interface was nearly built we did not do it that way but the next one I build will have it incorporated in the single unit.

Another neat idea is to use the existing Up/Down toggle from the Wing CB and use it on your radio. The basic principle is the same. It would require using a DPDT switch, or a TPDT (if you want it all in 1 switch) and 2 additional relays. The Up/Down of the wing uses the same principle of completing a ground circuit. Since the Kenwood I am using has the Up/Down on the Microphone you can do this with the wing. I intend to add this to mine in the near future.

Roger and I spent 3 or 4 evenings working on the interface. We ran into a few problems in design changes and ended up with 2 bad transformers. If you have all your parts together you could probably build a complete unit in a single day. It took 9 1/2 hours to install everything on my wing. That includes the Antenna, running all the wires, removing the center console to mount the radio head, installing the HAM/CB switch and about an hour or more trying to fit everything in the left side pocket (hence the above on moving the CD Changer module to the right side). If you already have a radio mounted then install would probably take you only a couple of hours and that would include running the power line and wires for the PTT. If you do not plan to use the wings PTT but will use an existing PTT then install time will be far less.



Closeup of the Kenwood in the Trunk and showing how little room it takes up.

Even with the Kenwood and my Alpine CD Player I still have more then enough room in the trunk.

 These 5 photos above are the finished installed product. I am real happy with the placement of the radio head. The Kenwood radio is a very compact piece of equipment and fit very nicely in my trunk, on the side shelf. I Velcro it to the side of the trunk and placed foam under it to keep it from bouncing or vibrating on the trunk plastic. The head and switch are all within easy reach and while there have been 2 occasions where I had the switch in the wrong place when I went to talk I think that using the existing PTT outweighs that little item.


Planned for the future:

Roger's original intention of this was to incorporate HAM, Radar and Cell Phone all into one box. I use the Walker CellSet and am very happy with that but I know Roger is going forward with his plans of incorporating Cell into his box. He simply ran out of real-estate on this current board and is one of the reasons it was stalled. He is now upbeat and ready to tackle a new interface that will have his cell phone interface included and allow him to get rid of the second headset cord. I am considering trying to find a box that will take the interface board as well as my existing cell interface and reduce the number of boxes and components in my fairing as well as the number of wires. What is absolute is adding the Up/Down function and adding the ability to use the wings external speakers and an external microphone. I am already working on all three of these options and I intend to build another interface to incorporate all of those. For now, this device works great. Audio and Modulation are great. We still have a slight issue with the Radar Detector side of this box. It works great with Roger's Valentine 1 but does not work so good with my Cobra. It will require changing and or adding some resistance to the mix.

If you find the schematics above difficult to read you can download the original WinDraft versions of the schematics from the link below. You can download WinDraft at http://www.ivex.com/ or if you do not want to mess with installing WinDraft then you can download the higher resolution JPG files from the other link below.

WinDraft Schematics.zip jpg_schematics.zip Schematics.sit


Well, that's it. This is the start of a project to fully integrate the HAM radio into the Goldwing components. It is off to a great start and I will keep everyone informed on how it progresses. Until then, talk to you on the air.


Page last Updated : 03/29/01 10:31 am