Dash Radio Static June 16, 2022, 08:26:11 pm Please help with this problem. I suspect that there are several resourceful folks here that will know what the problem is, which is: The stock, in-dash Sony AM/FM/CD radio in our 2017 F450 RB works flawlessly on AM and FM -- until the engine is running! Once the engine is started, all we get is loud static. Turn off the ignition and clear audio. The exterior antenna is up and solidly mounted. I am suspecting a ground short in the power line, but I am not a electrical expert whatsoever. I am fairly handy with tools, so if it is something I could probably fix, I am open to all suggestions.Thank you all in advance for your responses.
Re: Dash Radio Static Reply #2 – June 17, 2022, 01:06:38 am With the RV in park and engine running it you push the gas peddle does the tempo of the static change?
Re: Dash Radio Static Reply #3 – June 17, 2022, 02:59:29 am Good answer John. So Ray, did this suddenly start, or did it come and go, and finally get bad enough to be a problem? The power in the house batteries is it normal? The dash radio runs off of the house battery. If the AM radio was bad, but the FM was OK, that would indicate a bad antenna, or lead to the antenna. There are four speakers, do each of the speakers exhibit the noise? A 2017 radio should be fine, and quite likely it is either a wiring issue, or something serious with the engine. The high tension leads are really not there anymore since each spark plug has a 'coil over' arrangement where each spark plug has its own coil. There could be an issue with the alternator diodes. There are six for three phase full wave rectification. It is unlikely that a bunch of diodes went bad. Have you had any service done recently, new batteries? Engine work? Any new electrical attachments? The only thing that fits is a damaged antenna wire between the radio and the roof. An open or nearly open antenna wire can be found with an ohm meter RonB 2 Likes
Re: Dash Radio Static Reply #4 – June 17, 2022, 08:45:28 am Thanks, Ron. The static remains the same when the engine is idling or revved. All other radio functions are normal (CD player, clock, USB connections, etc.) regardless if the engine is running or not. We use the CD player or a Bluetooth audio 95% of the time when we are rolling. Only the AM/FM suffers when engine is on. We discovered the problem on the way home Wednesday when we tried to dial into the Giants game. We ended up playing the game from an iPhone app running thru the Bluetooth, which worked well, but of course is reliant on Internet connection (hit and miss in the Nor-Cal mountains). We have not had any recent service done on the engine. All the batt's are ok. I checked the battery terminal connections, and all was tight and no corrosion. I also suspect the antenna wire. I know how to remove the radio from the dash, but I guess (and this is a question) the best access for the antenna mount id from the top? Is there a better way to access the antenna from inside the coach to check the mount underside?
Re: Dash Radio Static Reply #5 – June 17, 2022, 01:14:58 pm Hi Ray; If you have the original manual, or can look it up on-line, the antenna connection to the radio is often by a short stub connector that is about 2" long coming out of the radio chassis. Possibly the plug is partially pulled out. This connection is just inches from the engine after all so the shielding may not be complete in that area. Abrasion of the radio lead near the engine is more likely. Rat damage, or a pinched lead can do it too. The cable for the radio in mine comes out of the back, crosses over to the driver side just over the steering column, and goes up the 'A' pillar under the Ford plastic cover. It then goes up into a channel in the wooden base of the cabover bed (the bed is wider than the chassis) and up to where it disappears into the wall and ceiling, and comes out at the roof antenna. If you have any antennas laying around, you would unplug the LD antenna at the radio, and temporarily plug in the other antenna and see if that eliminates the engine noise. If it does, that confirms that the issue is with the LD antenna or lead in. If not, it could be the radio itself. Now FM replaced AM for a reason. AM (amplitude modulation) has always been prone to noise issues, and FM (frequency modulation) is more resistant to amplitude spikes from external electrical noise. But FM doesn't travel as far. When stereo was added to the mix it pretty much wiped out music on AM. For your issue, listening to sports, you could consider Sirius XM. I have that, and it has an after market adaptor that transmits FM into the radio. It requires a very small antenna on the roof, but can be used for almost commercial free music. Since it is satellite based it will work when you have a clear sky view, anywhere in the U.S. There is an initial outlay and monthly fee though. And you can bring it inside the home too. (I'm not affiliated, or have any financial ties with SiriusXM). Let us know what you find out. RonB 2 Likes
Re: Dash Radio Static Reply #6 – June 18, 2022, 12:27:11 am Back when I was working the Tempest Testing a d security folks could come in and scan a room. Narrow in on something broadcasting and locat it. They were looking for low power things (bugs) but also worn equipment or grounds that got cut during a rebuild. I don’t know enough about modern ignition systems (but I’m good with points and a matchbook). Same with modern radio systems. But as sensitive as these things are there shouldve a directional antenna that can be dialed to the offending freq then narrow down the issue. 1 Likes
Re: Dash Radio Static Reply #7 – June 18, 2022, 11:39:48 am Quote from: John DaCrema - June 18, 2022, 12:27:11 amBut as sensitive as these things are there shouldve a directional antenna that can be dialed to the offending freq then narrow down the issue.In the past I’ve used a handheld AM radio and with earphone(s) to find where electrical noise (rfi) is coming from. With the radio away from everything, tune to a quiet portion on the dial. Plug the earphone(s) in your ear and turn up the volume. Now walk around and probe different areas looking for increased static. Crude but effective. Electrical noise (rfi) is generally broadband and will span the AM frequency range.- John 3 Likes
Re: Dash Radio Static Reply #8 – June 18, 2022, 02:14:42 pm Having done lots of rfi elimination while running mobile ham rigs, I'm having trouble figuring this one out. The fact that the noise doesn't change from idle to increased speed almost eliminates the engine itself as well as the alternator. On the other hand, you say it is fine till you start the engine. How about when you just turn the key to the "on" position, before starting the engine, any noise then? Some other sources of rfi to think about are the converter, again having nothing to do with starting the engine and any inverters you might have. Would love to hear the noise, any way to record it and post it?Rich
Re: Dash Radio Static Reply #9 – June 18, 2022, 11:15:03 pm Thanks, Rich -- No, I have not tried the test with just the aux switch position. I will certainly do that and get back to you. Also, I did not consider the two small inverters we use to power our DVD player and also to charge all of our varius phones and computers. I will also unplug those and see what happens and get back to you. Two helpful steps. Thank you.
Re: Dash Radio Static Reply #10 – June 18, 2022, 11:19:21 pm Thanks RobB and John. I will follow up and report back to all of you. Probably not until Monday.
Re: Dash Radio Static Reply #11 – June 19, 2022, 12:47:25 am "Modified sine wave" (more like "stairstep wave") inverters can put out some nasty hash. 1 Likes
Re: Dash Radio Static Reply #12 – June 19, 2022, 08:25:35 pm We followed up with the suggestions and questions you folks put to us and here are the results:No engine or ignition on. Sound is fine, no static on radio.Aux ignition position on, no static on radio.Engine on at idle, loud static, inaudible radio.Revving engine, no detectable sound difference in loud static.I used a small am radio with telescoping antenna to locate areas of static. I did this with engine on and with engine off. In each case, the static was noticeably increased each time I moved the radio to the cable harness that runs from the shelf to the back of the swing-out TV. In fact, the worst static was located on a 3 inch section of cable directly behind the TV and which is routed by LD along the swing arm of the TV bracket. When we unplugged the TV, the static was still present. I have purchased an after market sound bar that I mounted beneath the TV that came with the LD. The wiring for it is also routed along the same section of TV swing arm. I unplugged the sound bar and even unplugged the audio wires from the back of the TV. Static still present on the small am radio. When I withdraw the am radio by 2 or more feet, no static. Place it near the TV swing arm, static returns. If I placed the am radio on the cab dash, engine off, no static. Engine on, static returns. Popped the hood, engine running, used the am radio a few inches from running engine, inaudible loud static (as expected). All thoughts on the matter welcomed. And, thank you all.
Re: Dash Radio Static Reply #13 – June 19, 2022, 10:19:44 pm That was a good diagnostic summary. Is the TV antenna amplifier turned on? On my 2021 there are 2 switches behind the TV. One is for the TV power and one is for the 12v outlet. The amplifier on my 2021 is a Winegard SensarPro that comes on whenever the 1st (TV switch) is on. I believe the older LD’s have a small power switch on the amplifier itself where the coax cable enters the wall. In either case, make sure the amplifier is turned off.Since this is a new to you LD, I’d check all around to see if an inverter was added in the area behind the TV. I can’t think of anything else in that area that would be the source of the static.- John
Re: Dash Radio Static Reply #14 – June 19, 2022, 10:58:21 pm Oh, no. If I have given the impression that we bought the rig used, that is wrong. We are original buyers/owners. We took delivery in January 2018, but the rig was built on a 2017 chassis. Yes, I did fiddle with all of those switches and the amplifier, etc. People are probably wondering if we had ever noticed the problem in the past. I am a bit chagrined to say that neither of us recall the radio static issue prior to last week. We usually travel listening to audio mystery, spy, and crime books, usually via the CD player. My wife buys them by the truckloads. She loves them. Driving home last week, I suggested that we try and pick up the baseball game, and that's when I discovered the problem. At Lazy Daze on the morning of our delivery, I distinctly recall Todd showing us all of the features on the radio, but I am guessing that he was not running the engine at the time.
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