Electrical interference on radio from CPAP

When my clock radio goes off in the morning, electrical interference from the CPAP drowns out the broadcast. But it doesn't do so continuously, it does so in waves. Nevertheless, I can't make out anything being said on the radio. Once the CPAP is turned off, the radio returns to normal and is fine. I have searched the web seeking some filter or other device that can solve the problem. I have also tried plugging the CPAP and the radio into other outlets, but without success. Has anyone else faced/solved this problem?

Lionheart wrote:When my clock radio goes off in the morning, electrical interference from the CPAP drowns out the broadcast. But it doesn't do so continuously, it does so in waves. Nevertheless, I can't make out anything being said on the radio. Once the CPAP is turned off, the radio returns to normal and is fine. I have searched the web seeking some filter or other device that can solve the problem. I have also tried plugging the CPAP and the radio into other outlets, but without success. Has anyone else faced/solved this problem?

How old is this cpap machine? Because most of them have stickers to say they don't do that.

I received the machine less than a year ago.

My old Resmed S8 did not interfere with my clock radio. If the machine is approved for flying it should not be doing this at all.

Lionheart wrote:When my clock radio goes off in the morning, electrical interference from the CPAP drowns out the broadcast. But it doesn't do so continuously, it does so in waves. Nevertheless, I can't make out anything being said on the radio. Once the CPAP is turned off, the radio returns to normal and is fine. I have searched the web seeking some filter or other device that can solve the problem. I have also tried plugging the CPAP and the radio into other outlets, but without success. Has anyone else faced/solved this problem?

I would guess your station is an AM station?

Yes it may be from the computer in the CPAP or it may be from the motor but AM interference from devices such as CPAP is common.

Things to try:

Make the devices distant from one another.

AM antennas in most devices are directional (see: “Loopstick antenna” in http://en.wikipedia.org/wiki/Loop_antenna see “Radiation pattern and gain” in http://en.wikipedia.org/wiki/Folded_dip ... ded_dipole for the basic shape of the sensitivity). That is they receive more from one direction than another. So you may be able to maximize your station reception and minimize the interference by learning where the device picks up the best signal and then keeping your interfering device away from that path and in the least sensitive direction as far as the receiving device is concerned. While the CPAP is off rotate the receiving device and listen for more interference (static). Or perhaps with the CPAP on rotate the device for least interference and perhaps move the CPAP and try again.

Apply a ferrite core to the CPAP cord and/or an EMI/RFI enabled surge unit to the CPAP cord (e.g.(s) http://www.amazon.com/s/ref=nb_sb_ss_i_ ... Caps%2C346 ).

Have fun!

I'll give it a shot and report the results. Thanks.

LH, mine doesn't do that and they are back to back. My radio is on FM though. It may make a difference...Am vs FM.

Lionheart wrote:I'll give it a shot and report the results. Thanks.

One thing to note about the testing. AM stations often use a differant pattern at night which is often much less powerful than they use in the daytime. So you need to do your testing at night for it to be realistic. Say an hour or so after sun down.

Do you have a modem on your machine? Those modems have been known to cause issues with other electronics.

There was a modem when I first got the machine, but I had to return it after the first 90 days.

I know of two transmission paths that may be allowing the interference. One is the electrical power line where the CPAP is 'broadcasting' through the line. The other is direct emission from the device and then reception through the radio antenna. There may be other signal paths of which I am unaware.

A couple of things to try:
1) Go to you local Radio Shack and see if they have a RFI line filter that can be placed on the line to your radio to suppress interference from the CPAP.

2) Get a piece of aluminum foil and make a tent of it between the radio and the CPAP machine. Don't tent it over the radio as it will block the regular broadcast radio signals from being received. Radio transmissions are mostly straight line from the point of origin to the receiver. So placing a radio-opaque screen between the two devices may eliminate the problem.

Most of the replies involve shielding the radio from interference, however the real problem is that there shouldn't be any interference.

It's possible that the circuit board inside your machine has become wet or damaged and something is corroded and/or arcing.

You should probably have the machine looked at by whoever provides service for it. The interference isn't normal and indicates a problem with your CPAP machine.

Another one of those subjects that have come up over the years. Some have claimed/reported that they were receiving radio signals (like music playing) through their XPAP machines.


Den

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Wulfman... wrote:Another one of those subjects that have come up over the years. Some have claimed/reported that they were receiving radio signals (like music playing) through their XPAP machines.


Den

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http://blogs.wickedlocal.com/newton/200 ... z2wYm8GGlw

"The area already has two radio towers, which cause interference with appliances from computers and televisions to radiators and toilets."

Guest wrote:Most of the replies involve shielding the radio from interference, however the real problem is that there shouldn't be any interference.

It's possible that the circuit board inside your machine has become wet or damaged and something is corroded and/or arcing.

You should probably have the machine looked at by whoever provides service for it. The interference isn't normal and indicates a problem with your CPAP machine.

There is the possibility that the machine is faulty.

However, CFR 47 part 15 (see: http://en.wikipedia.org/wiki/Title_47_CFR_Part_15 ) requires only a "reasonable" limitation of spurious emmissions into the radio bands. If the desired station is very weak (and/or if the antenna of the reciever is oriented such that it does not "hear" the station well) the small emmission being many orders of magnetude (in terms of power transfer) closer can swamp the desired signal. If you can move the interfering source further away, or away from where the recieving antenna can "hear" it, or both, you can often clear the reception of interference.