Hi,

Perhaps you could try contacting the manufacturer of the air 
conditioning unit?

May be that they have had issues before.  I would think that there 
may be some requirement in the manufacturing process to make them 
reasonably rf proof.

Otherwise, the possibility exists that you could be affected by a 
transmitter in a nearby trailer?

Just a thought.


On 28 Jul 2006 at 15:08, T Behler wrote:

>     Steve:
> 
> I've contacted the maker of the antenna, and he has no other suggestions
> aside from being extremely sure that I have a good grounding system, which I
> think I do.
> 
> I don't really have a convenient way to try the rig on a 12-volt battery
> right now, but I may be able to work out something.
> 
> The quarter wave length of insulated wire attached to the ground lug of the
> rig sounds intriguing.  I assume that a quarter wave for 20 meters would be
> about 8 feet?  What gauge of wire should I consider, and where to I attach
> the other end?
> 
> Thanks, and 73 from Tom Behler: KB8TYJ
> 
> ----- Original Message ----- 
> From: "Steve Forst" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, July 28, 2006 3:01 PM
> Subject: Re: continuing RFI problems in travel trailer
> 
> 
> > Tom,
> > A lot of good advice thus far.  Can you take the rig off  the a.c.
> > completely, by  trying it on a 12 volt battery and see what happens?
> >
> > What about a quarter wave of insulated wire for 20 meters attached to the
> > ground lug of the rig?  Some people have success with this  in a home
> > station where  there is  rfi on a particular band, but don't know how it
> > would  play in a trailer situation.
> >
> > Have you contacted the mfg of the antenna?   He may have heard of
> something
> > similar from other customers and perhaps has an answer.
> >
> >
> > Good luck, Steve KW3A
> >
> >
> >
> > ----- Original Message ----- 
> > From: "T Behler" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Friday, July 28, 2006 1:19 PM
> > Subject: continuing RFI problems in travel trailer
> >
> >
> > > Hi, all.
> > >
> > > I hate to bug everyone again about this, but I continue to have a
> nagging
> > > RFI problem in the 18-foot Fleetwood Pioneer travel trailer that my XYL
> > > and
> > > I recently purchased.
> > >
> > > To review, when operating HF, I tend to cut off the air conditioner
> > > whenever
> > > keying up on CW.  I don't trip the GFI circuit breaker--I just cut the
> > > unit
> > > off, and it eventually re-sets itself and resumes normal operation
> within
> > > a
> > > few minutes.  The problem occurs mainly on 20 meters, although it does
> > > occur
> > > on certain frequencies in other bands as well.  I have found the problem
> > > to
> > > occur even when reducing my power from 100 watts, say to 50 watts.
> > >
> > > My HF rig is an Icom 718, and my antenna is a Predator screw-driver-type
> > > antenna mounted on the back of the trailer.  I use a device called the
> > > Turbo-tuner, to be sure that the antenna is indeed resonant on my
> > > operating
> > > frequency.
> > >
> > > The antenna itself is grounded to the bumper of the trailer, and I have
> > > installed two other grounds.  One is a ground from the 718 to the frame
> of
> > > the trailer, and the other ground is an earth ground that runs from the
> > > rig
> > > to a grounding stake outside of the trailer.
> > >
> > > I am getting more and more stumped with this problem, although I have
> two
> > > additional thoughts.  Let me run them by you here;  I just don't want to
> > > spend more money unnecessarily on this problem:
> > >
> > > 1.  I run the 718 with an MFJ Mighty Lite switching power supply.  I
> think
> > > it's the 4125--it has 25 amps surge, and 22 amps continuous.  Could this
> > > type of supply be causing the problem via some sort of stray current
> flow?
> > > Should I try an old transformer-type supply, such as an Astron RS20, to
> > > see
> > > if the problem disappears?
> > >
> > > 2.  I have the rig's power supply plugged into a relatively inexpensive
> > > power strip, since I sometimes plug my laptop into it as well.  Is there
> a
> > > higher-quality power strip that I might want to look at?  Some have
> > > suggested a power strip with something called a power isolator in it,
> but
> > > I'm not quite sure what it is.
> > >
> > > Please give me your feedback on both of these possible suggested
> > > solutions.
> > > Or, if you have any other suggestions, please send them to me.
> > >
> > > Some have suggested trying to put a capacitor across the leads of the
> > > trailer's thermostat unit, but I really am hesitant to do that, at the
> > > risk
> > > of somehow voiding the warranty on the temperature control system.
> > >
> > > Thanks for anything you can suggest.
> > >
> > > 73 from Tom Behler:  KB8TYJ, Big Rapids, MI
> > >
> > >
> > >
> >
> 
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Keith

- - - -

Keith Barrett
email <[log in to unmask]>
Website www.barrettpianos.co.uk
Amateur radio callsign gw4nby
Corntown, South Wales