Two small electrical issues on 5th wheel

fpresto wrote:
If your TV is saying no signal then it is not likely to be interference. I would guess that the light, fan and antenna amplifier are all on the same circuit and for some reason are pulling power form the amp when turned on.

X2

All of these are 12v items, so your not going to get electrocuted.
For a couple of bucks go to Radio Shack and pick up

Model: 89410 | Catalog #: 55047557
NTE 89410 0.1uF 50V Ceramic Disc Capacitor


These are not polarity sensitive so you can't hook it up backwards. Place the capacitor across the power leads to the fan and see if it stops the interference. You can just twist the wires for a trial but put some electrical tape on the leads, no fancy twisting just fold it over the wires for easy removal. This way they don't touch any conductive surface and pop a fuse.

I've used this a lot of times to filter out noise for ham radios.

If your TV is saying no signal then it is not likely to be interference. I would guess that the light, fan and antenna amplifier are all on the same circuit and for some reason are pulling power form the amp when turned on.

The bathroom fan is likely a permanent magnet unit. These have brushes (mine are brushless but are not OEM) and do generate a lot of radio hash Television is radio.

Are your bedroom lights Incandescent (Silent) LED or Florescent Some of the latter are very very noisy as well and can cause Radio Interference or in this cast Television Interference RFI or TVI) .

So somehow the fan and lights when turned on are drawing from the 12v power that runs in the coax to power the amplifier in the antenna. When those are off, the 12v gets to the antenna ok.

How long has this been going on? Can you tie in the start of this with some event like a leak through the coax boot not being in place outside on the antenna's roof mounting? (it can slide up the coax, leaving a hole to inside) Maybe water corroded some fan/light wire spot to create WAG #1 situation. Grasping at straws of course.

I suppose WAG #2 is more likely than WAG #1 and is easier to check. The DC fuse panel can be unscrewed and the wires are behind it to the fuses.

About the TV screen, the good picture goes away and a "no signal" comes up on the screen. As soon as the bed lamp or fan is turned off the picture comes back.

OP, please clarify "lose the picture." Does it go out like when the booster is turned off, or is the picture still there but full of interference lines etc. ?

It doesn't have to be touching the ant cable, just being close is bad enough when it comes to RF interference.

The DC wires for the bathroom fan and the lights are in the bedroom ceiling and could be next to the coax that goes to the antenna by the crank up handle. That coax is powered 12v when the antenna boost is on. There is a coax connector (exposed metal) in the ceiling close to the crank up handle that joins the coax from the Winegard panel to the coax coming down in the antenna mast.

So WAG #1 is a DC wire has a break in its insulation that is touching the coax connector by the crank up handle.

You can get at that coax connector by taking the crank and twirler off and see the hole in the ceiling. Then hook (finger or bent coat hanger, whatever)on any coax you can see and pull it down out of the hole till the connector is out and tape it up so no exposed metal. (You can't get at the DC wires most likely, but you can get at that coax connector)

WAG #2 is the fuses in the DC panel for the TV, fan, and lights have a loose wire or two in the fuse panel mixing things up.

I suspect it's electrical interference from whatever you're turning on. It could be the motor on your fan is worn out or just radiates a lot of RF noise. Are your reading lights fluorescent or LED bulbs, some of these lights are also known to radiate badly. Fixing these problems might include replacing the motor/bulbs or installing capacitors to filter the noise.

A second possibility is that these items are all on the same electrical circuit and it has a poor connection. The small draw of the TV ant. amp wouldn't cause a problem but the larger draw of fans and lights would cause a large voltage drop. Does the fan run when you turn it on? Do the lights come on at full brilliance when you turn them on? If not, then I think this is your problem.