5061 - want to interface to HLN1220B

[n3lqk]

I have a F5061 mobile with the remote kit.

I also have a motorola HLN1220B handset kit, and a selection of speakers, including an HSN 4035 powered amplified speaker.

I have also the 5061 service manual, the documentation for the above mentioned handset/speakers, and decent knowledge of circuits and how to solder.

Goal of project:

Installed 5061 in my 2011 4runner. Control head in the cab, draw in the back, with the HLN1220 handset & hanger mounted in the back trunk area with a speaker that could be controlled from the back of the vehicle.

Why:

Want to be able to be getting gear, reading maps, treating patients, etc, in the trunk area of the SUV and be able to hear/answer the radio without walking back to the driver seat.

I understand I can run a splitter for dual mic input off the mic jack; I am looking for a more "elegant" install than splitters, etc. I would prefer to run all the wiring for this extra speaker/microphone off the back of the drawer unit.

Again, I have the service manual and relevant documentation. I am looking for any insight helpful before I start on this endeavor.

Thanks much for any insight or encouragement.

Tim
Albuquerque

 

[n3lqk]

also what type of connector plugs into the speaker jack on the back of the radio?

 

[cabletech]

You have the radio? You have the service manual? (I think yes). Then all the info you need is there.

3.5mm mono plug for specker.

Where do you plan to connect the rear handset?

If I remember correctly, the radio option connection/plug on the back does not have enough drive for any 'stright connected' mic.

Info should be in the manual.

 

[ramal121]

Hoo boy! OK, marrying a Motorola handset to an Icom radio. That is a project for sure. You have a service manual for the radio, how about the handset? There's a big leaf switch in the handset and a diagram of the ins and outs of the thing is almost required.

Lets start with the speaker. Not too bad to figure out. When you plug an external speaker into the radio chassis (a 3.5mm phone plug), the one in the control head is cut off. You'll have to provision for splitting external speakers front and rear if you want both. Pay attention to impedance. Both should be 8 ohm to be safe. One could be the amplified speaker, really safe as it is a higher impedance input and it's volume can be adjusted to match the other. Normally the rear speaker is run through the cradle so when the handset is lifted it switches off and receive is heard only in the handset. Kinda moot if the front speaker is still blaring. Your call.

The mic is the booger. You can hook it to the DB-25 connector of the chassis (need to solder jumper "F" in the radio to make that work). Two gotchas though. The mic in the Motorola handset needs a DC voltage "bias" to make that work. That can be accomplished by an appropriately sized resistor from the mic line to say a 12vdc point. This will power the mic. It will also be great to put a capacitor on the mic in line to the radio to block that DC from getting into the radio. The other thing is Icom specs the DB-25 mic in line at 300mV for 60% transmit deviation. Motorola mics, on the other hand, provide around 150mV when talking loudly. Probably a little light for the transmit volume to hook straight to it. A small amp may be needed to bring the level up. The alternative is to connect to the mic line from the control head. Icom uses a dynamic mic and its drive is around 25mV. In this case the handset mic may require padding down to make it acceptable. You can probably tap the control head mic in the chassis somewhere too. You'll probably have to use the PTT line from the control head also instead of the one on the DB-25.

I will put out a disclaimer, I've never put a Motorola handset on a 5061, but have done quite a few on Kenwoods. I don't think this is an impossible project, but it's far from plug and play and will require a bit of R&D. Are you up for it?