Will two table radios always be in phase, out of phase/

[micky]

Technical qustion about wave valleys and troughs and if two radio playing the same station will be in phase wrt all frequencies, or if some will cancel out?

And why is it low frequencies are famous for cancelling out when out of phase when high frequencies are just as likely, 0.5, I think, to cancel each other out?

Can I just turn off one radio and turn it on again so that the total odds over both times have increased that by the second time the radios will be in phase?

I have a radio and tv in one bathroom but neither in the other, which is smaller and adjoins the bedroom. Sometimes I want to hear the radio which only gets 'loud' if you are in the same room. I can hear it from the bathroom but not enough to understand what is said.

I have another table radio, KLM, expensive, that I had for about 33 years when the speaker switch started to fail**, and I turn that one on too, to the same station, also at maximum volume, and I can hear in the bathroom just fine, but I wonder if some frequencies are out of phase from one radio to the other, cancelling each other, and I'm not hearing them.

It seems to me, if one radio is farther from the transmitting antenna, by 1/2 wave length, the speakers in the two radios will always be going in the opposite direction from each other. Maybe.

In my case, the radios are one above the other, so the distance from the xmtr is very similar. But what about within the radio, when the heterodyning frequency starts. What if it starts have a cycle after the first radio?

**So I bought the second radio. The first one has a pushbutton switch meant to connect/disconnect a wooden-cabinet stereo speaker, which I have no room for, and unless I get the switch just right, no sound comes out at all. (even the on/off momementary contact switch no longer works well, after only 33 years, maybe using it at most 6 times a day, so that 6x365x33=66,000 times. Aren't switches supposed to last into the millions of times? --- It's failing isn't nearly as bad, because I just keep pushing until it works. The speaker switch OTOH has a spring that pushes it out, past its sweet spot, so now it's hard to get to connect at all.

[Dean Hoffman]

Ask the guys in sci.electronics.design

[Badger]

No, please don't.

[Ed Cryer]

Let's rule out Hertzian waves from Net speeds to begin with. If you have an FM radio and a Wifi radio in the same room, there'll be a very noticeable discrepancy. This phenomenon is so well known that I don't need linger on the cause.

Added to that, you may have two wifi radios together, but processed by different hardware/ software. And here again the cause needs no explanation.

Your second radio with the dodgy on/off button doesn't even contribute to the mix; and it won't do so until it produces some output sound. A faulty switch is a different problem from an echoing, out-of-sync cacophony of sound.

Ed

[Ed Cryer]

My best radio is in my bathroom. I didn't put it there; it was in place when I moved in; it comes through the vent fan which switches on with the room switch. I've been trying to figure out for years which station it's tuned to. Mostly it seems classical, like a choir singing, but now and again it has a bom-da-da-bom rhythm of rock music. I once heard it playing Werewolves of London.

If you solve your problem, let me know. I'd love to find out which station my bathroom is tuned into.

Ed

[Rachelle Walenski]

Are the radios powered by the same 120v phase or on opposite legs (180 degree out-of-phase)?

[rbowman]

Don't you have another radio? It would be trivial to scan the frequencies until you get a match. Doesn't the UK require broadcast stations to periodically identify themselves?

Perhaps it's a pirate with eclectic taste. The local university has a low power FM station that's all over the map depending on who the DJ is for the slot.

[Martin Brown]

The radio will convert it to DC anyway so that doesn't matter.

Chances are one will be a few hundred ns time shifted relative to the other since the amplifiers in each stage of detection are unlikely to have exactly the same delay or frequency phase response.

Propagation of sound waves in the room will have a much larger effect on what you hear. Positioning of the speakers relative to hard surfaces.

If you really want massive flanging effects try two different digital radios or SDR decoders within earshot. The difference in delays then can be fractions of a second or seconds when compared to an FM radio.

DAB is completely useless in an emergency situation unless you have a shed load of batteries. Uses a set every 8 hours of run time. A decent FM radio will run for a week or more on just one set of batteries.

[Bill Gill]

Not a problem. There are 2 different problems that you may be talking about. The difference in phase of the RF signal will have no effect. The RF part of the signal is taken out in the receiver and only the audio is there to be affected by the location of the 2. And that will have no effect, because the wavelength of audio signals is over 9 miles for the high end (20 kHz) frequency and goes up from there as the frequency goes down. There will not be enough difference to have any effect.

And it isn't even April 1.

Bill

[trader_4]

You're confusing two different things, the RF carrier signal and the audio output from the speakers. With the radios tuned to the same station the audio is going to be either of the same phase or 180 off, depending on how the speaker in each is wired.

[trader_4]

Irrelevant.