Amateur Radio in Prius

I put an Icom 207 in my 2006 Prius. This is a 45Watt 144/444 Mhz FM transciever. Despite many warnings in the owner's manual, it works like a charm.

You wire the radio to the little 29 AMP Gel Cell battery in the right rear corner of the vehicle. I used a trunk lid NMO mount for the antenna. I put the radio in the little plastic cargo tray with Velcro strips. I ran a remote kit forward, and put the control head in the little drawer in the console. No noise, no problems.

Erik Westgard

I am very happy. No noise, no issues. I have the radio Velcro'd to the right side of the cargo tray liner below the trunk. The remote control head for my Icom 207 fits in the drawer in the center console. I have the mic extension cord tie-wrapped to the passenger seat track. The whole setup is 100% invisible. For my next trick I want to put in HF.

I think the issue in the owner's manual is harming the air bag system or having it go off. I would not want a lighter powered "rube goldberg" setup in the cabin.

BTW the car is a wonder. Gets 49 mpg when I drive, 55 when the wife drives. Can't get her out from behind the wheel. I give a demo ride a week for neighbors, etc.

HF works great. Put in a second trunk lip mount to the left side near the top of the hatch. Not a peep of noise.

I put the radio in the base of the under-trunk plastic tray with Velcro strips. The 207 control head fits in the console drawer sideways when not in use and is held on with velcro in use. The mike goes to a separate jack strapped to the pasenger seat mount.

After 10K miles the car is still amazing. Years ahead of any other vehicle on the road. The cruise contrl works at 30 mph so keeps me out of trouble in small towns.

Erik

I recently installed a Icom IC-2200H into my 2001 Toyota Prius.
I snaked the radio's power cable behind the left seat near the door, and attached the leads to the gell battery in the rear left trunk.
I working cautiously with safety first -- didn't want to get zapped.
I attached the mag mount antenna on the roof and turned the radio on.
Success! Everything worked.
Then I turned the ignition on (the 1st gen prius has an ignition).
The computer was not happy -- I got a red triangle alert light
up top next to the speedometer, and Battery Main Error message on
the computer display. The car ran fine.
I detached the cables, and the computer was still not happy.
The next day, my clock was reset, the red alert was gone, and the
computer display was back to normal. There was still a yellow check
engine light. The car runs fine.
My suggestion is to be very careful on the power drain used by the radio, and also take care with the hydrogen gas discharge. I'm not sure what the
secondary battery was designed to handle, but the computer is real finicky.
I would like to know if anyone else has managed to successfully install a 2m amateur band radio in a first gen prius.

Have been using Yaesu 8800 (2m/440) in my 2008 Prius with no problems. Also been using an old GE 2m for APRS.

There are several unused fuse circuts in the fuse box under the dash.

I tapped the fuse box for both Ign and Batt hot circuts, and placed a little black box at the base of the dash with power poles.
I also tapped the 12V battery in the trunk for a batt hot power pole outlet in the trunk space. Good for recharging portable batteries on the go. Or running a portable rig from the trunk as Incident Command.

So far, I've been using mag mounts on roof, but I found a nice short trunk lid 2M antenna that I can put on the hatch, and drive into garages without twang, twang, twang...

Absolutely NO problems or malfunctions on the car with two 50W 2M rigs running (and gps recievers, nav computer, scanner).

The Prius drive system inverts 200v DC from the battery into 600v AC for the drive motor.

It's possible that if there is some RF leakage from the power inverter, it's being read by the radio as incoming signal. This would be more of a problem in the AM radio spectrum than FM.

Is there any sign of interference in your "broadcast" AM radio reciever?

If you want a "home made" detector for RF interference (or for lightning) you tune an AM radio to a "dead" channel that has no station broadcasting.

RF noise from the car's ignition system, or alternator shows up on the radio as a high pitch whinning sound that rises and falls with engine RPM.

Nearby lightning sounds like a sudden crackling noise, with the volume being a rough estimate of the distance to the lightning.

AM radio's are far more vulnerable to picking up stray RF noise. One reason why music stations have transitioned to FM broadcast.

An update: I installed the CB radio back on my Pontiac Bonneville and it works great. However, I got stuck in crawling traffic this morning, on the way to work, next to a Prius. The radio registered lots of RF interference every time he was moving and we passed each other. A few days ago, as I passed one at high speed there was a noise blip, but I wasn't sure the Prius caused the blip. Now I'm sure. Prius' are a little hotbed of RF noise that deffinitely can affect CB radios.

Another response that I received yesterday from the editor of a CB magazine said to use a Wilson 1000 antenna and see what happens. He has no confidence in cheap compact antennas. But I don't want to throw more money at this problem based on a hunch or bias against inexpensive products. That's why I'm here. Has anyone successfully installed a noise-free CB in a Toyota Prius? And if so, what did it take to do it?

Tuning the antenna to the Prius may be a possible solution if I had a SWR, but I don't. Spending money on one for 1 installatiion doesn't make much sense to me, especially since I don't know that this is really the problem. Has anyone else gone through this process of getting a CB successfully installed on a Prius?

The Prius is a hotbed of RFI on HF. So bad I won't even attempt an installation. Here are some great links discussing this matter.

Brad - W4BJM

http://perens.com/works/hobbies/ham/prius/rfi/

http://wa8lmf.net/mobile/prius/index.htm

Now I want a 100watt CB !

Hi

Afte extenisve shielding modifications to my 04 Prius, I have been successfully operating HF mobile for over two years.

Here's roughly what I did...In working on my Prius, with significant help and encouragement from Alan, K0BG, I developed techniques for identifying the location of noise sources coming from the Prius. In the case of the 04 Prius the DC-DC converter (the so-called Synergy Drive) radiates a 'huge' amount of broadband noise from abt 2MHz up to abt 15 Mhz.

After grounding and shielding the DC-DC converter and adding ferrites to each cable entering and exiting the box (not an easy job!), I was still left with S9 and greater noise. It seemed that HF mobile operation would be impossible! Clearly I needed techniques to locate, then reduce sources of noise.

It became apparrent that electrical fields generated by the DC-DC converter and other digital boxes are so large that they induce a large amount of HF signal voltage into the various vehicle wiring harnesses.

The harnesses travel from inside the engine compartment through the firewall, are distributed along the vehicle ending up in the rear of the vehicle. These harnesses are not shielded, and hence act like antennas and radiate noise.

Some of the major sources I identified, included four digital boxes, the exhaust and the ignition system. Another ham, using similar techniques, identified that the regenerative breaking system generates noise while the breaks are applied!

I used two techniques to locate noise. Firstly I used a small resonant whip antenna and attached it via a length of coax to a manpack radio (IC 703). The radio was tuned to a ham band, turned on and left outside the vehicle (there's a reason why). Using the antenna as a wand, I walk around the vehicle waving the wand over the vehicle surface listening for peaks in noise (hot spots).

On my 04 Prius this identified the front windshield wipers as major radiators of noise. By simply grounding the wipers, noise was reduced(on all bands) by several S units. I also identified the front lights and the rear lights as noise sources (at least S6 noise). I also identified that the vehicle roof, at the back, was the least noisy location to mount an HF antenna!

Next, the wand is waved over the inside of the vehicle. I was surprised at the results! When I did this in the rear hatch (after opening the hatch)I found S9 plus 15 noise.

I then switched to my second technique. I disconnected the 'wand' and connected a length of coax terminated in a small 2 inch loop. I used the loop as a probe and identified specific noise sources inside the hatch (after removing the carpet and plastic molding. That's how I found that the Prius NiMh battery box is poorly shielded in one spot, found a digital control box that was radiating noise, and determined that the wiring harness was radiating noise.

After the loop identified major hot spots. I then used 3M 1181 copper foil shielding tape to shield, and then bond to ground, the offending hot spots. The tape is wrapped around the offending digital box or wiring harness. Seams are tack soldered and the assembly is grounded to the vehicle chassis.

In each case, after shielding/bonding/grounding I re-measured the noise using the loop and wand technique and found considerable reductions in received noise and 'hot spots' disappeared making for improved reception.

As a bonus, I realized that there were 'good' and 'bad' spots to mount my screwdriver antenna. In the case of the Prius it seems that the radio mounting location inside the Prius may also be of concern.

By the repeating the above processes throughout the vehicle eventually I could Operate 20 and 80 meters with noise levels below S3 and S5 respectively. 40 was still a problem with noise levels at S7.

I finally took apart the DC-DC inverter (synergy drive) and added bypass capacators and proper ferrite beads to each of the HV lines exiting the synergy drive, and ensured a good ground bond between the sections of the synergy drive case parts.

The COP ignition units and wires all require wrapping with 3M1181 and ferrite beads.

The antenna is a Hi-Q 3.5 screwdriver, centre roof mounted supported by a Breedlove brass mount, with aluminum re-enforcing plates under the roof sheetmetal. I now have less than S3 to S5 noise on all bands, using an ICOM 7000 with pre-amp turned on. The ICOM 7000 screen display is fed to the 04 Prius Navi display using the Coastal Electronics interface. The ICOM's audio gets inputted to the Prius sound system the same way.

Signals on 20 are sometimes amazing and I work much DX.

The noise has been reduced such that I can easily tell when a non-shielded vehicle is driving near me - you can hear other vehicles electrical noise!

The above amounts to a huge investment in time and effort. I'm not sure i would do it gain.

73 - John VE3XKD