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  1. #21

    Now I want a 100watt CB !

    Now I want a 100watt CB !

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  3. #22

    I have a 2003 Prius and am

    I have a 2003 Prius and am considering buying an IC-7000 with little Tarheel Antenna for it. What is your HF RFI situation with your IC-7000 and your 2007 Prius ? Terry sends ...

  4. #23

    Hi Afte extenisve shielding


    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

  5. #24

    08 prius cobra 29 ltd bt

    08 prius
    cobra 29 ltd bt 25watts
    gettn pwr from cig lighter
    wilson 1000 mag mount center of roof
    swr 1-1
    no problems no noise
    i also run a scanner and radar detector
    had cobra 200gtl dx 10 meter pushing 100watts+ wired to batt in back but too mutch drain radio wouldnt work right so i had 100 amp truck batt straped down in back and had no problems except to charge batt back up.
    with wilson 1000 and ant matcher got swr to 1-1 and made contact to japan from central california

  6. #25

    I know this is an older

    I know this is an older post, but im going to add my 2 cenats anyway.
    I have an 05 prius. Im running an export 10/11m rig with power capabilities of 1kw PEP on AM - No Problems What so ever. I did the optima yellow-top upgrade, the EV Only mod, and some other misc things to the car. The car is already bonded extremely well from the factory. I have not added 1 bonding strap to this day.

    I have added a 3.5 farad cap between the battery and the amp. I also have an icom 706mkIIg (i am a ham too) which absolutely sucks on SSB because of noise. Go figure - the junkie export rig is quiet and the expensive hf rig is horrific.
    I have also added every mix of ferrite to this car trying to eliminate the noise for the icom with no luck. The AH-4 tuner just amplifies the noise! lol.
    As far as RFI goes- no problems what so ever.

    I drilled the hole in the center of roof (beer can is sturdier than the prius roof) and have 3 backing plates holding the puck mount, and im feeding it with LMR400. Very sturdy, great ground, and I usually run a 7' tall open coil on the roof. I have a hitch and when I want to DX, I park it and run two 1/4 waves on the car setup as a parasitic reflector which gives the car an additional 3.5db of forward gain, and still have no rf issues with the car.

    The noise that everyone experiences in their HF rigs is caused by the 3 phase, and the inverter pump.

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