Radio integration

During the downtime after the Goldwing crash I decided to tackle integrating the Kenwood TK-250 portable with the GL2Way kit. We'd already installed the Kennedy system on John's bike. My master plan was to get the GL2Way setup working then also install the Kennedy system on my bike and do a comparison.

The challenge will be the interface cable. My portable isn't on GL2Way's list of supported radios for their dual plug harness. I bought one anyway in hopes it would work. If nothing else it will be the basis of something I can cobble together. I also bought a cheap headset that I could use for parts and testing.

I started the project with some documentation to assist me...the Kennedy KW14 cable diagram and a Kenwood pinout Pete from GL2Way had sent me earlier. However, they didn't agree. Since we had successfully used the Kennedy system on John's bike the KW14 diagram must be correct...assumption.

No matter what type of radio you are interfacing with the principle is pretty much the same. You have to:

- get the receive audio from the radio to the bike.
- get the microphone audio to the radio.
- key the PTT (push to talk). 99% of the time this is done by connecting the PTT line to ground.

With high hopes I connected the portable to the GL2Way and keyed the bike's PTT switch. No transmit. No surprise. At this point I could have a couple different problems. The cable might not be right, or the GL2Way might not be set to use the FRS (second radio) port. According to the documentation you quickly toggle the Goldwing PTT button three times and the GL2Way will beep to let you know it has switched from the CB port to the FRS port. No matter what I did I wasn't getting any confirmation beeps, and using my multimeter I couldn't see where any of the FRS port pins were changing state.

The next day I posted on the GL1800riders forum asking if anyone had any experience getting the GL2Way system to switch ports. Pete posted and asked if I had went through the programming sequence to make the GL2Way enable the FRS port. Programming sequence? I never heard of it. Several others posted that their instructions didn't mention it either so Pete posted it:

- Switch to Channel 7
- Squelch up-up-down-down all within 1.5 seconds
- You should hear three beeps
- Switch down to channel 18
- Switch CB volume up until a '1' shows on the screen to enable
- Hit the PTT to exit setup

Armed with this new knowledge I went home that evening and gave it a try. It worked like a charm. The GL2Way will beep twice when switching to the FRS port and once when switching back to the CB port. It remembers the port you've selected even after powering off the bike.

Now that the FRS port was selected I went back to trying to get the portable to transmit. No dice. I had ohmed out the GL2Way cable and I knew to ground the PTT line the base of the 2.5mm jack needed to be grounded. I had rewired the cable so it would do that but it still wasn't working.

The GL2Way circuit board.

I removed the board from the housing to do some probing and promptly killed the board. An email from Pete revealed I had popped a fuse. It looked like a resistor to me. I wired in a fuse and everything worked again. Probing didn't reveal anything to me. I quit for the night.

The next evening I decided to take apart the headset. It functioned properly with the portable. I ohmed out the wires and made a schematic of it. Hmmmmmmmmmmmm. It didn't match the Kennedy KW14 harness schematic that I was using as gospel. Hmmmmmmmmmmm. The headset DID match the pinout Pete had sent me. Hmmmmmmmmmmmm. Since starting this project I had gotten a Kenwood TK-250 service manual. It confirmed Pete's drawing was correct. As I stared at the pinout Pete had given me it started to make sense. I thought the pinout was labeled by function, but Pete had labeled it as to where the GL2Way signals needed to go. The fog was finally starting to clear.

I mapped out part of the GL2Way microphone circuit, and using Pete's suggestions, came up with the following circuit. It made more sense when I could visualize it. I could now see how the PTT circuit would find its ground when the circuit is keyed...through a resistor to the Mic+ line...through the relay, inductor, transformer, and back to ground in the portable.

I cobbled a cable together using the GL2Way cable as a base and the plug end of the headset cable. The headset cable wiring was super small and there wasn't any shielding.


I hooked everything up and it worked! There was some humming, and the receive audio was low, but it worked.

That night as I lay in bed I started wondering if the relay on the GL2Way board was negatively triggered. If it was it would make a great place for a PTT line. I wandered out to the garage at 3am (I have trouble sleeping) and checked. No such luck. It got me to thinking though, and the next day I came up with the above circuit (my changes in blue). This eliminates the capacitor in the Mic+ line. I had also noticed that although the FRS port connector only uses four wires all six connections had connectors in them. I could solder wires to them.

That evening I went to Radio Shack and got parts. For the cabling I used shielded speaker cable with molded connectors. I couldn't find any cable with molded 3/32" connectors so I used an adapter.

Sidenote: Is it just me, or does Radio Shack have a pitiful selection of electronic components anymore? And what they do have is expensive.

The tiny thread-thin headset wiring on top. The GL2Way wiring in the middle. The Radio Shack shielded cable on bottom.

The 3/32" adapter heat shrank to the cable.

I soldered what will be the PTT line to an open pin.

I unsoldered an unused +12V connection from the board (purple arrow) and used this to pass the PTT line to the relay I added.

Here is the finished cable. I hooked everything up and it worked much better. The hum was gone. The microphone volume was loud and clear. The receive audio is still low but I'll work on that.

Now that I had the GL2Way system in a working state I installed the FRSet4 system. I covered a lot of the installation steps when we installed one in John's bike, but I'll show mine too. This isn't the finished installation but just enough to get it working. Since I have the seat off and a hole into the trunk the installation will literally take about ten minutes.

The intercom adapter connects between the passenger headset connection.

I ran the cable into the trunk...

...and connected it to the FRSet4 unit.

Connect the radio-specific cable to the FRSet4...

...and the other end to the radio.

Connect the PTT line. For a PTT switch I'm gonna use one of the switches I bought and mount it in the Windbender switch housing. Windbender sells the switch housings for $35.

Connect the power. You're done.


Sadly, the comparison is now a moot point. A couple months after I purchased the FRSet units Kennedy Technologies announced they were getting out of the motorcycle electronics business. (Update 2015 - Kennedy Technologies in now back in business!)

The FRSet4 has loud and clear receive/transmit audio right from the start. If the FRSet receive/transmit audio was a '10' and '10' then the GL2Way was about a '3' and an '8'. I'll continue to fiddle with the GL2Way audio to see if I can improve it.

Both units use Micro-Fit connectors, but the ones on the GL2Way unit are a pain in the ass to get on and off. Granted, most people will connect them one time and that's all. I'm a big fan of D-sub connectors for rugged applications. They're bulkier, but they attach easier, can be screwed tight, and offer good RFI protection.

The GL2Way unit is the most versatile. It can connect a CB, second radio, and another audio source to it's third input. I'd love to see a GL2Way version 2 with better connectors, a dedicated PTT line for the second radio, adjustable audio, etc. With the demise of Kennedy Technologies they stand to increase their market.

For my setup the Kennedy FRSet4 system was $190. The GL2Way is $309 (the CB module is another $210).

Update April 2012 - We took a trip to Shoals to eat at Bomacs so we finally got to try out the radio systems. They sounded great sitting in the driveway, but at speed Mike's was pretty much unrecognizable and John's had a lot of background noise. When we headed home we changed channels from to and put the radios on low power. It worked better. I could understand what everybody was saying but there was still a lot of background (wind?) noise. We'll be trying lots of different things to optimize communications before our trip this summer.

Update June 2012 - In preparation for South Dakota trip we bought larger windsocks for the microphones. This helped a lot with wind noise. When they left my house after some pre-trip maintenance I talked to them for a few miles on my base radio. They both sounded good.

Update July 2012 - On our trip to South Dakota I had the ability to use both the Kennedy and GL2Way systems. I got better reports using the GL2Way system. The other guys also liked the courtesy beep the GL2Way system has. Since the GL2Way system uses the CB connection you can listen to it via headset or bike speakers. It also mutes the other audio sources. The other guys were using the Kennedy systems. Mike's audio was loud and clear and he had good range the entire time. John's range and audio quality would vary.

I have since found out the antenna connector on the Kenwood portables we used don't have a ground connection. This might be part of the problem of sometimes poor performance. My next project is to interface a mobile radio to see if it works better.

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