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Re: [RFI] [Amps] new mobile amps from THP

To: Jim Brown <jim@audiosystemsgroup.com>
Subject: Re: [RFI] [Amps] new mobile amps from THP
From: David Jordan <wa3gin@erols.com>
Date: Wed, 11 Jan 2006 10:22:09 -0500
List-post: <mailto:rfi@contesting.com>
SOunds about right.

I ran mobile in an Isuzu Trooper (100 watts 40m).  Door locks would 
activate on voice peaks (installed .01mfd caps across all the diodes on 
the door lock controller board and problem was solved).  Went to 80m and 
10 watts killed the engine.  Stayed off 80m.  Folks should check all 
systems in a parked position before going on the road.

Now have a Ford Sport Trac...run 1KW on 40m and no problems.  The 
ignition noise from the engine puts out a better signal then I do on 40m...

Mobiling is great fun and an even greater challeng these days.


Jim Brown wrote:

>On Wed, 11 Jan 2006 06:30:40 -0800, Bill Turner wrote:
>>I like the idea of HP mobile, but I still hear concerns about RFI to 
>>the car's electronics. Has anyone had any experience with this lately?
>YES! I just put a 100w HF transceiver in my 2006 Toyota Sequoia and drive 
>to CA with it. Power straight from the battery, antenna a Hamstick on the 
>luggage rack, shield of coax bonded to a big bolt holding the luggage rack 
>to the roof. Antenna works great, and I had lots of fun on 17m CW and SSB. 
>Had to turn off the car's climate control when I worked CW, because it was 
>speeding up when I keyed the radio. 
>BUT -- the Toyota Sequoia is an EMC nightmare -- when I fired up on 20 SSB 
>and called a 15 sec CQ, the Toyota's main computer crashed, leaving me dead 
>in the water in the middle of the Nevada desert! No fun. I managed to get 
>rolling by pulling the power lead off the battery to reset the computer. 
>Prior to installing the rig, Ron, K9IKZ and I poked around with an ohmeter 
>to see what was bonded to what so that we could find a decent connection to 
>the body for the antenna and understand how the vehicle was shielded. What 
>we learned is a disgrace -- two bolts a few inches from each other holding 
>the luggage rack to the body read 60 ohms between them. Bolts at opposite 
>ends of the luggage rack and on opposite sides are 3-6 ohms apart. A copper 
>strap supposedly tying the battery negative terminal to the body reads >10 
>ohms to those bolts and to the body near the bond! In other words, almost 
>nothing is bonded together, all the bolts and washers have paint between 
>them and the body. 
>Because I'm in the middle of moving from Chicago to CA over the next few 
>months, I won't have time to dig into this and clean it up. I will, of 
>course, add ferrite chokes to power leads for the ham gear and to what 
>senstive electronics I can find. And I'll bond everything I can find, 
>including body parts, tailpipe, hinges, etc. But what a mess! This is 
>absolutely SHAMEFUL!
>Jim Brown K9YC
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