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Re: [RFI] Kenwood TM-D700

To: "David Jordan" <wa3gin@comcast.net>, <rfi@contesting.com>
Subject: Re: [RFI] Kenwood TM-D700
From: "Hardy Landskov" <n7rt@cox.net>
Date: Wed, 29 Oct 2008 08:48:34 -0700
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Not odd at all. The alternator is varying the 12 VDC and frequency 
modulating the transmitter. Look at the 12VDC line with a scope and you will 
see what's happening. I believe a big common mode choke is in order or try 
running the TM-D700 power cables directly to the battery as the car battery 
looks like a 1 Farad capacitor. Sounds like the TM-D700 is not decoupled 
from the 12 volts very well.
GL N7RT

----- Original Message ----- 
From: "David Jordan" <wa3gin@comcast.net>
To: <rfi@contesting.com>
Sent: Wednesday, October 29, 2008 8:00 AM
Subject: [RFI] Kenwood TM-D700


>            Hi folks,
>
>
>
> This one is a bit odd.  My buddy has a Ford F-150 and installed in the 
> truck
> is his TM-D700 dual band VHD/UHF radio. We chat during our drive into work
> in the mornings.
>
> Almost without fail when he is transmitting at least once during the 30 
> min.
> drive I will hear what sounds like a siren on his audio Whrrrrrrrrrrr
> starting at a high pitch and slowly going down in audio tone freq. He has
> grounded the radio, etc., yet the weird noise continues to occur.  Last 
> week
> I installed a TM-D700 in my Ford Sport Trac and guess what - now he says I
> have the same odd occurrence of the erratic whine syndrome.
>
>
>
> My radio is also grounded extensively as I run 1KW on 75 and 40m.
>
>
>
> Thoughts and recommendations welcome.
>
>
>
> 73,
>
> Dave
>
> Wa3gin
>
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