Tom,
The charger in your r v may be a smart charger.  If it is there probably is 
nothing you can do about the interference.  I have both types of chargers 
and the old heavy transformer , linier type should not make any noise.  My 
smart charger is so no communication can be done.  Get a different charger 
perhaps.  73Ed   K7UC

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From: "Tom Behler" <[log in to unmask]>
Sent: Monday, May 14, 2012 5:53 PM
To: <[log in to unmask]>
Subject: Getting rid of hash caused by battery charging unit in RV

> Hi, all.
>
> I know we have discussed similar topics before, but I have an issue in my 
> RV
> that is now affecting my HF set-up big-time.
>
> Specifically, there is a built-in charging unit for the house battery that
> seems to be creating more and more interference on the HF frequencies. 
> The
> interference occurs when the charger is in either the "use" or "store" 
> mode.
> I know that the charger is causing the interference, since when I switch
> from "use" to "store
> ", the interference goes away for a few minutes, until the charger re-sets
> itself, after which time, it gradually returns.
>
> When we unplug the RV from the electrical service at our camp site, the
> interference disappears completely.
>
> As far as I know, since the charger is directly wired into the RV, there 
> is
> no way to turn it completely off.
>
> Does anyone have any simple remedies for me to try in order to get rid of,
> or at least lessen this interference.  It is so bad that it makes the
> 40-meter band unusable, which is why I was not on Saturday's round table.
> 20 meters isn't much better either, which is rather discouraging.
>
> 73 from Tom Behler: KB8TYJ