Amateur Radio in a Prius

First off: Thanks to everyone posting their installs in this forum! It makes planning your own much easier with regards to parts, antennas, and cable routing.

I've seen a number of folks talking about hooking up a relay to one of the spare accessory points in the fusebox to turn off/on the radio with the car. Has anyone done this, and do you have any pics or schematics of how you did it and where you installed the relay box?
Thanks!

 

I have been around 2 way radio for decades, never heard of this technique.
Normaly good redio install practice dictates both PLUS and NEG power cables run directly to the battery. NO INTERRUPTIONS. The transmitter needs all the amps and volts it can get when in XMIT mode. Use the on off button supplied with the radio to power up the rig.

 

I just did this for stepfather (K0SLO) in his Civic Hybrid. The power button on his transceiver is broken so it had to go to an accessory point. I pulled the bezel off the lower portion of the dash to get to the cigarette lighter and tapped the positive there, and found a good chassis ground for the negative.

I agree best practice is direct connection to the battery, which is pretty easy on the Prius since the battery is in the back. Install an Optima Yellowtop at the same time

 

Greg,

As KK6PD said, drilling the hole was a bit nerve-wracking and finding a way to seal it was a big P.I.A.. It is an awkward angle with little room to work and I didn't want try to figure out how to take the hatch door off. I figured out if I used some line and tied the door so it would not fully open I could get the optimal working room.

I drilled the smallest hole I could to get the factory finished cable with connector through it, which was 5/8". I could find rubber grommets that fit the hole well or I could find grommets that fit the cable, but I could not find a grommet that was tight on the cable and hole and if I had I probably couldn't get it over the connector. I opted for a grommet that fit the hole tightly, making it easier to get the grommet over the connector. I filled the gap between the cable and the grommet with Silicon (RTV), then reinforced and backed that water tight electrical tape. Then I applied three coats of Silicon over the entire outer area. Each successive coat covering a slightly larger area then the previous coat.

No leaks so far and I still check the area about once a month.


TKY

 

Seilerts,

I researched installing a second 12VDC battery in series, using a rectifier from Hellroaring Technologies, and replacing the existing 12VDC battery. I opted to connect directly to the factory 12VDC battery. When I have to replace the 12VDC, I will switch to the Optima Yellowtop or whatever improved battery is on the market when the time comes.


TKY

 

With regards to the relay for power.
Get a relay - the black 1"cube type are inexpensive and very common. You can find them at most auto parts stores. They use 1/4" push-on terminals or you can buy a socket for them.
Run your battery cable to the relay with the negative connected to one side of the coil and continuing to the "output". I install connectors on the "input" and "output". I use Molex as they are inexpensive and available at most electronics parts places.
The positive goes to the relay. The relay output to the connector.
Now, because you have connected the negative to the coil already you just have to run one wire to the accessory line. In a Prius cabin, accessory is available from either the accessory power connector on the dash or in the console. Note that connecting the relay coil to either of these points will not load the fuse noticeably as the coil draws less than 100 mA. In a Prius, either of these points is truly "accessory". They are only on when the car is "ready" or in "accessory".

I find this technique very easy and convenient. You can concentrate on running the power directly from the battery (with an in-line fuse -at- the battery positive), then plug in your relay anywhere in that line you like. You can even put in a "T" with the Molex connectors and have one line always on and one switched.

One more thing. I always solder a diode across the coil of these relays. Reverse polarity of course. It will absorb any coil pulses generated. I use a 1N4003 for this.

 

David - Thanks for the input, I actually arrived at this conclusion and installed it last Friday. After much soul searching I realized the best installation option was a relay controlled, fused accessory jack in the rear of the vehicle. It provided flexibility for radio usage, air pumps, rectifiers, etc.

I fished wiring to the cabin up the driver side door frame floor channel, then under the carpet under the drivers seat to the inside of the central console. I used 18ga automotive splices to tap into the armrest accessory jack (green wire & while wire with black stripe), and routed my speaker wire and control head wire via the same path. The control head and phone mount are attached to a flexible arm mounted to the passenger seat hold-down bolt, and the speaker is in the under-console storage area.

The relay is connected to the battery by a fused lead off the positive terminal, and the accessory jack is grounded by a similarly fused lead to the frame ground. (10A fuses in each.) I will eventually mount the radio mounting frame in the back plastic bin, but it is currently at home in TN and I am deployed to Tampa for a while longer yet.

I found that the Diamond K400 mount was good, but I had to bend the frame support tab up at about a 30 degree angle to allow the hatchback to close properly. The frame support tab is built assuming that the trunk/hatchback surface is flush with the frame, while on the Prius the hatchback is about 3/8" recessed. I was lazy and just ran the cable through the hatch, I am going to monitor for leakage (none yet!) in the hopes that I don't have to drill a hole for it.

Thanks to all the advice from the folks on this forum that made this install possible!

Vince

 

Just changed the radio in Pearl to a Kenwood D710A.

In the process I added another speaker. So one under each front seat, secured to the carpet with velcro.

The control head is mounted on a right angle bracket just under the CD storage pocket (so the door will still open fully), using velcro tape to hold it to the dash. Much better than my original location (see previous posts).

The radio is located in the same place as before, between the left hand storage pocket and the rear of the car under the hatch floor. Easy to get at, but hidden, taking up no usable space.

This time I installed the relay I have been discussing above. It's in the hatch area under the floor zip tied to the harness that crosses the rear of the hatch area.

The cables are run under the carpet on the hump. To do this you need to remove the rear seat (but not the seat back), remove the drivers side rear door sill (it just pulls off), and remove the bolt holding the drivers seat inside rail to the hump. If you also pull the three plastic pins holding the carpet under the rear seat you should get enough slack in the carpet to feed the cable under the console.

Remove the console by removing the two screws at the front bottom (one each side) and the two bolts in the storage cubby near the back of the console. The rear cupholder assembly just pulls off (pull up). In there you will see two cables/connectors. Disconnect them and you can remove the console. The larger one has "accessory" power (brown wire - but test before trying to use it). This is the wire I used to control the power supply relay.

So I ran two speaker cables back to the radio, the accessory wire back to the relay, and the control head cable back to the radio, all over the hump in the rear, along the body under the rear seat to the left side, and under the seat back to the under-floor hatch area. I also had to make a microphone extension cable and it is also run along with the others (I suppose I could have purchased one). I used a Cat 6 network cable and changed one end to be the reverse of what it normally would be so I had pin to pin continuity from one end to the other with a female to female adapter on one end. The supplied control head cable was long enough with some to spare.

Took a few hours in all, as I remembered a combination of "how to remove" procedures from three different vehicles. Funny. What was also funny was I actually had to insert my FOB into the slot for the first time after removing the console when I was testing to find the accessory wire. The SKS sensor is in there. I always thought it was in the steering column.

Fun with radios.

 

Hi Glen,

As a former commercial two-way radio installer I never understood why the amateur radio manufacturers put a fuse holder in the negative lead (maybe over engineering). Motorola, GE, and Johnson never did. These included radios for VHF Low Band, High Band, UHF 450-470, and 800-900MHz. Our typical installs for the average domestic automobile would be to supply power to radio as you suggested minus the 20A fuse in the negative radio line. The only time we would actually go back to the batteries negative terminal is if we were having a noise issue, otherwise we would ground to the vehicle chassis/body.

My first 2 meter install (87 Ford Escort) prior to the above installer position actually had one of those fuses in the negative lead that would occasionally blow. This would leave me with the antenna shield as my only ground source (radio bracket was mounted to plastic). I wound up removing that fuse and tying the negative lead to the batteries ground point and never had an issue with the radio. None of my installs since then include the negative line fuse holder.

I realize every vehicle presents it's own challenges. My 2 cents worth.

73
John
K2JLM

 

Hi John, WELCOME to PC !! You may note by checking the date of post, that you're responding to a post that's about a year old ... not that I haven't resurrected a few zomby threads myself. Also, if you follow the qrz database back, you'll see that glen's been licensed back since the days of Marconi. . . . . back when you had to be able to send/receive 20wpm of code in front of a live FCC employee. Those folks made great Elmers ... for everything from sizing torrids, to building auto screwdriver tuners. but I digress ...

 

The negative fuse it to protect everything in the (admittedly unlikely) case of the battery ground cable breaking. It is more likely that the cable would have been unhooked for maintenance reasons and not reconnected. When you try to start the car, the system will look for alternative ground paths for several hundred amps of starting current. I do not know what the result would be for a non-fused radio as I always put in the negative fuse...and the battery ground never broke to test it all.

 

Try a lip mount on the hatchback like a Comet CP-5M mount with a Diamond dual-band SST-7 antenna.

----- Bob ----
W1OLD

 

Bringing an old thread back to life again as it appears. Brand new to PriusChat, but not to discussion boards. My passion is my '94 Landcruiser that's now a weekend toy, off road camping/expedition vehicle, treading lightly everywhere I go. My 2013 Prius Gen 3 is my daily commuter car - hmmm...11mpg if I'm lucky in the LandCruiser and you all know in the Prius.

Anyway, I've been running a Yaesu FT-8800r in the truck for years and just picked up another one on the closeout pricing of the 8800. Yaesu is dropping the dual band 8800 in favor of the quad band 8900. On to the heavily used search button here for everything ham related, etc and I've learned a lot already. Thx to KK6PD and several others for sharing their install knowledge and experience.

Mounting the base unit to the radio is the no brainer in the cubby hole on the DS rear. Power will be run over to the battery with fused wires on both + and - side, again a no brainer IMHO.

Now the decision(s) - where/how to mount the face plate and speaker. Several good suggestions and pics on the speaker below the center console and that's where mine will go. Whether I mount it back against the rear cubby or up above the cig lighter/ heated seat buttons or just on the floor of the storage area is yet to be decided. The face plate to the radio is another matter. I've seen the blendmount, the Ram passenger seat bolt on mount, suction cup/glue pad on the dash, velcro under the LCD display and a discussion at least of a Garmin GPS with a suction cup on the little window between the front windshield and DS window. I'm leaning toward a Ram suction cup mount in the little window (be damned CA Law on placement of suction cup mounts) as I adverse to drilling into the dash or using the glue pads Ram has on the dash too. As stated on one of the many threads I've read, a suction cup mount on our front windshield just really isn't an option because of the severe slope and distance from the driver to the bottom front of the windshield. I took the face plate and plastic cradle for a 'dry fit' above the mirror for the blendmount and it'd be very tight. That and the tight fit of the headliner against everything I think would make running the power and mic cables a real pain. If I'm wrong there, someone speak up!

I'll probably run a 6-pin mic extension from the face plate down to the center console or somewhere nearby to mount a mic holder. I've thought about just leaving the mic and cord on the face plate with it mounted to my left, but I prefer using the mic with my dominate right hand, perhaps because that's where the mic's in my truck are! I've seen some great pics of the mic mounted on the lower portion of the center console here too.

For the antenna, I'm using the same Diamond K400C mount I've used off my Landcruiser hatch for years. I have one for my ham antenna and one on the other side for my CB antenna (yes, I still have the ancient CB tech in the truck too as not all, just most, offroaders have gone ham). I had the CB long before my ham license. Both those mounts have taken an absolute beating from branches, washboard roads, etc. I'm going to run a Comet SBB-2 antenna on the Prius. I use an SBB-7 for onroad and a little flexible SBB-1 for offroad in the truck. At this point I think I'll just lay the coax over the rubber seal near the bottom of the hatch to minimize any leakage and then down into the cubby. I've done my truck the same way and no leaks for 6 years. I like the balls some of you have shown drilling a hole at the top DS of the hatch and then back filling with a grommet and silicone. I'll only go that route if I get any leaking with my easy way.

Again, thanks for all the posts here on ham radio installs. Look forward to sharing my install when I get around to it.