Ok, you are making progress. I see your PM to me, btw, but it seems best to answer it here since the next guy who stumbles onto this thread won't benefit from a private response.
If I follow what you said correctly you have no TV interference when running the TV on an antenna or the DVD player. You only have interference when using the VCR. Correct?
If that is true, is it still true when the TV is powered by the inverter?
What happens to the signal from the VCR when the VCR is running from shore power through the extension cord? If everything is good when the VCR is powered that way then ferrite beads on the VCR power cord might help. It is also possible however that the VCR doesn't like the AC waveform from your inverter. In that case ferrite won't help, you will have to find an inverter for the VCR that generates a clean enough AC waveform to make it happy -- if they exist.
His interference occurs when the inverter is under heavy loads even if the vcr is plugged into shore power.
klhutch wrote: Ok, you are making progress. I see your PM to me, btw, but it seems best to answer it here since the next guy who stumbles onto this thread won't benefit from a private response.
If I follow what you said correctly you have no TV interference when running the TV on an antenna or the DVD player. You only have interference when using the VCR. Correct?
If that is true, is it still true when the TV is powered by the inverter?
What happens to the signal from the VCR when the VCR is running from shore power through the extension cord? If everything is good when the VCR is powered that way then ferrite beads on the VCR power cord might help. It is also possible however that the VCR doesn't like the AC waveform from your inverter. In that case ferrite won't help, you will have to find an inverter for the VCR that generates a clean enough AC waveform to make it happy -- if they exist.
Ken
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.
It seems like a worst case of the VCR not liking the invreter, must be some something to do with the VCR reading of the magnetic tape.
Even it the TV and the VCR are plugged into shoreline power once the inverter is switched on I get the interference. Therefor the inverter must emmit some kind of "noise" , broadcast through the AIR that interferes with the VCR.
frecku wrote: It seems like a worst case of the VCR not liking the invreter, must be some something to do with the VCR reading of the magnetic tape.
Even it the TV and the VCR are plugged into shoreline power once the inverter is switched on I get the interference. Therefor the inverter must emmit some kind of "noise" , broadcast through the AIR that interferes with the VCR.
Thanks for that post, it makes sense, whether I want to peruse this or simply buy another VCR is a whole different issue.
The smallest item I plugged in so far was a 750W kettle, and the largest 2500W combination of large house toaster and kettle, absolutely no discernable level of interference.
I hope to do the "trigger" wattage test, have to find enough light bulb receptacles.
For your "trigger wattage test" you might get one of those small halogen bulb work lights. They only cost about $5.00 and can use either a 300 or 500 watt halogen bulb. I tried one outside at a campground when we were with a group. I put it outside about 8 feet from the motor-home, aimed at the side of motor-home, for indirect lighting. It still lit up multiple sites. The different bulbs will cover down to 300 watts. A regular lamp with 3-way bulb could cover lower wattages.
Mark
Mark & Jan "Old age & treachery win over youth & enthusiasm"
2003 Fleetwood Jamboree 29
frecku wrote: It seems like a worst case of the VCR not liking the invreter, must be some something to do with the VCR reading of the magnetic tape.
Even it the TV and the VCR are plugged into shoreline power once the inverter is switched on I get the interference. Therefor the inverter must emmit some kind of "noise" , broadcast through the AIR that interferes with the VCR.
It seems like you have proven that the interference is being radiated from the inverter or its wiring to the VCR, I agree. That is not really a head scratcher though. An inverter is supposed to make AC Voltage and current at 60 Hz, or 50 Hz in many parts of the world. It certainly does that but in the process of doing so it makes signals at much higher frequencies too, frequencies high enough to interfere with your TV or VCR in this case. At 50/60 Hz the current it generates does not radiate through the air very efficiently because nothing in your MH is anywhere near large enough to act as a good antenna to "launch" radiated energy at those frequencies. At much higher frequencies the wiring and the inverter components themselves can act as good antennas. Your inverter basically generates radio waves in the course of its operation as do all electronic devices. If there is a good enough antenna in the path of high frequency current it will radiate energy just like a radio transmitter.
The FCC interference regulations have long recognized this. They divide all electronic devices into one of two categories: intentional radiators (radio transmitters) and unintentional radiators (everything else, including radio receivers).
Unfortunately, in the small confines of a MH even the inverter's intended 60Hz output could cause a problem since it can couple magnetically to the VCR. It does not have to radiate away into space to do that. It seems unlikely that the VCR would be bothered by 60Hz energy coupled in magnetically however, since that occurs in most home based VCR setups.
If the interference is being radiated into the VCR then getting a separate inverter for it and the TV will not solve the problem. X-ray shielding is not likely to help either. Wrapping the VCR in aluminum foil may help, just as a test. Routing as much of the inverter wiring as far from the VCR as possible may help. Putting the VCR somewhere else far from the inverter may help. Use a longer video cable to the TV to allow this. All of these things can be done as temporary measures just to see what the effects are. If a solution falls out of the testing you can then consider how to implement it in an acceptable permanent fashion.
I think what you should try to do is to first separate the VCR as far as possible from the inverter and its wiring to kill the interference with it and the TV running on shore power. Then without moving anything power the TV from the inverter to see if the problem is still fixed. If it comes back try some ferrite on the TV power cord. If you can get that to work then try connecting the VCR to the inverter power too. Once you know that can work you can start to work out how to get the TV and VCR back into acceptable locations without interference.
Well I braved the weather and did the tests suggested by members here to check the RFI. The results were the same weather the TV VCR connection was made on shoreline power or inverter power.
First, the "trigger" test, alone the TV/VCR show no interference, it takes an additional load of 500W to create the interference, this was achieved by adding 60, 100, and 250W light bulbs to the line.
Second, the aluminum foil wrap, this was amazing, once I completely enveloped the VCR in regular aluminum foil there was no interference on the TV, as hard as I tried even at 2500W load, NOTHING.
Third, the AM radio test, under additional 1000W toaster, load, unshielded VCR, there was a lot of static on the radio and then it completely cut off about 1' from the inverter, the DC cables, even the inverter AC cables all the way back to the main panel box ( although not as strong )
This RFI does not extend far only chest high, about 5' then the radio signal is clear once more. The inverter and all the cables are on the ground, I thought I would be in the clear since the TV/VCR is located 8' from the inverter and 5' high off the ground.
To my astonishment when I brought the AM radio to the VCR the interference was huge, as high as when it was close to the inverter with the signal completely cutting off.
Or possibly use the tapes to burn some DVDs for personal use.
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