Signal interference from air conditioner help please - AVS | Home Theater Discussions And Reviews
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post #1 of 112 Old 03-23-2015, 06:17 AM - Thread Starter
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Signal interference from air conditioner help please

Hi guys. Hoping someone can help as I am spending money to solve this and thought I was getting somewhere but have discovered I am not.

I have a 55" Hisense LED TV. Its a 50K390PAD if you must know.

Anyway. I have a portable window air conditioner / conditioning that's brand new a works great. It's summer and I'm in Australia so yes I do really need it on with the temp's we get in Queensland.

The issue is when the compressor switches on or off the TV signal is interfered with, appearing almost like you knock the antenna over and stand it back up. I am also paranoid about this possibly doing damage to the TV eventually as I think its more of a power spike thing than a reception thing.

Now the power for the air con is on a different power point. I cannot say different circuit as I do not know the house circuit schematics, but its not drawing from the same power point.

So anyway, I went and bought a UPS battery back up hoping that if the TV ran off that it would clean up the power signal to the TV.

It is still happening, just not as bad. It's still enough to make the sound go away for a second and the picture to jump. I'd say about half as bad as what it was.

How do I stop this happening?? The UPS just cost me $130 so I am a bit peeved that this did not solve the issue.
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post #2 of 112 Old 03-23-2015, 07:09 AM
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Try a different air conditioner?
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post #3 of 112 Old 03-23-2015, 07:18 AM
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Move your antenna as far away from the A/C unit as possible. The motor start circuit is radiating RF energy that the antenna is picking up, the interference is not coming through your mains.

Check your fly lead, if one is being used, and make sure it's well shielded and of good quality.
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post #4 of 112 Old 03-23-2015, 07:59 AM
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This sounds like the air conditioner has a high start-up current and is causing a brief but large voltage drop. Plug an incandescent light bulb into the same outlet as the TV and see if it dims when the compressor comes on. If it does then that's what's happening. If not then it is an RF problem. If it's a voltage drop problem then the TV and the AC are probably on the same circuit and one needs to be changed.
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post #5 of 112 Old 03-23-2015, 08:56 AM - Thread Starter
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Thanks so much for the tips guys. I will def look into both.

I am using rabbit ears as I live very close to the TV stations.
At one stage I had tried one of those amplified antenna's which was a mistake as all it did was make the signal too strong. However where the antenna is plugged in, there is an exposed connector left over from the amp (where the amp used to intersect into the fly lead).

I might go see if I can by a good shielded fly lead and take the old garbage off to see if I can shield it as much as I can. It's a room so there's only 'so far' I can get away from the air con. So if it's RF then I am going to have to go down the road of shielding.

I will grab a lamp and plug it into the circuit of the TV and watch it to see what happens with voltage. I was sure it was a voltage drop from the compressor, but RF makes sense as well. So investigating both makes sense.

I will report back in a day (it's 2am - past my bed time here).

Thanks again.
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post #6 of 112 Old 03-23-2015, 09:02 AM
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Can you run the TV off the UPS by battery power alone (without the UPS connected to the mains) for testing? That will tell you 100% if its RFI or a power surge delivered via the mains.
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post #7 of 112 Old 03-23-2015, 09:07 AM - Thread Starter
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By the way - pic of air con and pic of the fly lead connection I was referring to.
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post #8 of 112 Old 03-23-2015, 09:08 AM - Thread Starter
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Quote:
Originally Posted by ADTech View Post
Can you run the TV off the UPS by battery power alone (without the UPS connected to the mains) for testing? That will tell you 100% if its RFI or a power surge delivered via the mains.
Thats a great idea... I'll try that ..
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post #9 of 112 Old 03-23-2015, 01:33 PM
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I would attack the problem at the SOURCE....the A/C....by adding a high quality RFI/EMI Filter....which is available as an in-line product....or included in SOME Surge Protectors....or you can order with pigtails (or built into the Chassis Power Socket) for installation INSIDE the A/C.

I checked Australian JACKSON and POWERLEADER products that claim an RFI/EMI Filter is built-in, but could NOT uncover any SPECS....perhaps the package has them. Here in the US, GOOD 120 VAC Power Strips provide 60-75 dB suppression below 100 MHz and AT LEAST 45 dB in UHF Band...and the CHEAP RFI/EMI Filter products don't have specs, so they don't WANT you to know how mediocre they might be (you usually DO get what you pay for):
http://www.ji.com.au/products/PT0811
http://www.ji.com.au/pdfs/PT0333_DATASHEET.pdf
http://www.ji.com.au/pdfs/PT8888_DATASHEET.pdf
http://www.powerleader.com.au/pdfs/L54000_DATASHEET.pdf

You might also want to check Amateur Radio sources for in-line power RFI/EMI Filters, with NO Surge Protection MOV's.

Since the A/C has a large in-rush current when it turns ON....be sure the current rating of the Surge Protector or RFI/EMI Filter is about TEN TIMES the published RUNNING current rating for the A/C.
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post #10 of 112 Old 03-28-2015, 03:29 AM - Thread Starter
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Well it is resolved now.

I ended up making my own EMI / Av line filter from parts I purchased at JayCay at Aspley. I bought an EMI filter, standard 240 volt cable, safety box and some crimps. Put it all together and ran the TV's power through that.

As an additional I also purchased some copper RF blocking tape and wraped some around the antenna connections near the TV.

I also bought a 4G in line filter for the antenna. This was probably over kill but it wasn't expensive and I do have a 4G phone. I wasn't getting 4G interference but thought while I was at it may as well be complete.

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post #11 of 112 Old 03-28-2015, 03:34 AM - Thread Starter
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Quote:
Originally Posted by holl_ands View Post
I would attack the problem at the SOURCE....the A/C....by adding a high quality RFI/EMI Filter....which is available as an in-line product....or included in SOME Surge Protectors....or you can order with pigtails (or built into the Chassis Power Socket) for installation INSIDE the A/C.

I checked Australian JACKSON and POWERLEADER products that claim an RFI/EMI Filter is built-in, but could NOT uncover any SPECS....perhaps the package has them. Here in the US, GOOD 120 VAC Power Strips provide 60-75 dB suppression below 100 MHz and AT LEAST 45 dB in UHF Band...and the CHEAP RFI/EMI Filter products don't have specs, so they don't WANT you to know how mediocre they might be (you usually DO get what you pay for):
http://www.ji.com.au/products/PT0811
http://www.ji.com.au/pdfs/PT0333_DATASHEET.pdf
http://www.ji.com.au/pdfs/PT8888_DATASHEET.pdf
http://www.powerleader.com.au/pdfs/L54000_DATASHEET.pdf

You might also want to check Amateur Radio sources for in-line power RFI/EMI Filters, with NO Surge Protection MOV's.

Since the A/C has a large in-rush current when it turns ON....be sure the current rating of the Surge Protector or RFI/EMI Filter is about TEN TIMES the published RUNNING current rating for the A/C.
As my previous comment I ended up putting in an in-line EMI filter on the TV's power cable.

To put one on the air con power do you reverse the EMI filter?? Or does it still go on the same way? Just curious as it would be nice to hit this at the source rather than letting the voltage spikes run through everything else aside from the TV....??
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post #12 of 112 Old 03-28-2015, 06:14 AM - Thread Starter
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Dam it... it was going great for around 4 hours.

The air con compressor just switched OFF and the screen pixelated again...

So I have a UPS, a surge protected power board and an inline AC filter on the TV power and RF shielding on the antenna plugs....

I might try the inline filter on the air con power and see what happens... Can't see it helping tho. If it can't stop the power spike on the TV's power line then it's not going to stop it on the air cone power side.

Its only done it once but if it's done it once it will do it again.

Does not seem to do it when the compressor switches on now, only off... so looks liek the voltage drop is OK its a voltage spike when it switches off which is odd considering all the gear I have on the power line to the TV.
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post #13 of 112 Old 03-28-2015, 07:49 AM - Thread Starter
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You know - this ONLY happens when the television is on live TV via the antenna.

When the TV is on the HDMI channels it does not do this at all.

I'm thinking this is more of an RF antenna interference issue than power again you know..... But I guess it could still be power playing with the in-built tuner I am not sure which.
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post #14 of 112 Old 03-28-2015, 09:15 AM
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The A/C is obviously generating RF Interference (EMI) into the TV Band(s).....which can be radiated into the air directly from within the case....or much more efficiently via an attached "Antenna"...i.e. the POWER CORD. The TV is "probably" picking up this EMI via it's Antenna, but conduction via the Power wires can also be an issue. Ideally an EMI Filter should be mounted WITHIN the A/C's case as close as possible to the SOURCE of the EMI.....but when mounted at the END of the A/C's "Antenna" it would also be very effective in SHORTING OUT EMI so it is neither Radiated into the air nor Conducted to the TV via the Power wires.

PS: When the active Magnetic Field in the A/C motor is suddenly switched OFF, it generates a "BACK EMF" that can result in a SPARK jumping across the Switch (or Relay if used) Contacts....this is the SAME mechanism using in automobile Ignition systems....when the Ignition Coil's Magnetic Field is interrupted, a Spark is generated, jumping across each attached Spark Plug. A well-designed A/C would have a Spark Suppressor (probably a Capacitor and Resistor in Series) across it's Power Switch...or Relay if used:
http://en.wikipedia.org/wiki/Arc_suppression
http://www.industrologic.com/mechrela.htm
Note that the Spark Suppressor's Capacitor voltage rating must be several times (e.g. 4x or more) the operating voltage (240 VAC) [Which may require putting multiple (say) 300 VAC Capacitors in SERIES] and the Resistor's power rating must be greater (2x or more) than the amount of power (actually Energy) expected when suppressing the spark...which is presumed to last a certain number of milliseconds (so 1 Watt should be enough).

I don't know the particulars of your particular EMI Filter, but some are symmetric and doesn't matter which way it's connected....and some are more complicated and work a bit BETTER in one direction than the other....depending on whether optimized to protect against EMI ENTERING the device or optimized for protecting against EMI EXITING the device (the usual case):
http://www.digikey.com/Web%20Export/...f?redirected=1
Note that the Common and Differential Mode Noise differences occur at frequencies MUCH LOWER than TV Bands.....where it is effectively Symmetric....so you should be able to use it either way....simply match up the Power Plugs....

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post #15 of 112 Old 03-28-2015, 09:37 AM - Thread Starter
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Originally Posted by holl_ands View Post
The A/C is obviously generating RF Interference (EMI) into the TV Band(s).....which can be radiated into the air either directly from within the case....or much more efficiently via an attached "Antenna"...i.e. the POWER CORD. The TV is "probably" picking up this EMI via it's Antenna, but conduction via the Power wires can also be an issue. Ideally an EMI Filter should be mounted WITHIN the A/C's case as close as possible to the SOURCE of the EMI.....but when mounted at the END of the A/C's "Antenna" it would also be very effective in SHORTING OUT EMI so it is neither Radiated into the air nor Conducted to the TV via the Power wires.

PS: When the active Magnetic Field in the A/C motor is suddenly switched OFF, it generates a "BACK EMF" that can result in a SPARK jumping across the Switch (or Relay if used) Contacts....this is the SAME mechanism using in automobile Ignition systems....when the Ignition Coil's Magnetic Field is interrupted, a Spark is generated, jumping across each attached Spark Plug. A well-designed A/C would have a Spark Suppressor (probably a Capacitor and Resistor in Series) across it's Power Switch...or Relay if used:
http://en.wikipedia.org/wiki/Arc_suppression
http://www.industrologic.com/mechrela.htm
Note that the Spark Suppressor's Capacitor voltage rating must be several times (e.g. 4x or more) the operating voltage (240 VAC) [Which may require putting multiple (say) 300 VAC Capacitors in SERIES] and the Resistor's power rating must be greater (2x or more) than the amount of power (actually Energy) expected when suppressing the spark...which is presumed to last a certain number of milliseconds (so 1 Watt should be enough).
But do you reverse the EMI filter or not?

The EMI filter for example has load coming in one side (the power from the wall) and going to the TV on the other side. If I mount an EMI filter to the AC is it mounted the same, or in reverse? SO that Load is on the AC side going to the wall socket?

This may sound like a dumb question to someone experience with these but I am trying to understand exactly how they work. Obviously there is a capacitor etc inside to catch the voltage spikes/drops, but it seems to me they are designed to filter out the spikes coming in from the power socket so that the device (TV in the case) on the other end does not suffer from those power spikes.

So if I am to put an EMI filter on the thing thats causing the spikes, would you reverse the EMI filter to catch the spikes going TO the power source, which then goes into my house and works it's way into my TV??
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post #16 of 112 Old 03-28-2015, 10:48 AM
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Quote:
Originally Posted by Nicholas Goss View Post
But do you reverse the EMI filter or not?

The EMI filter for example has load coming in one side (the power from the wall) and going to the TV on the other side. If I mount an EMI filter to the AC is it mounted the same, or in reverse? SO that Load is on the AC side going to the wall socket?

This may sound like a dumb question to someone experience with these but I am trying to understand exactly how they work. Obviously there is a capacitor etc inside to catch the voltage spikes/drops, but it seems to me they are designed to filter out the spikes coming in from the power socket so that the device (TV in the case) on the other end does not suffer from those power spikes.

So if I am to put an EMI filter on the thing thats causing the spikes, would you reverse the EMI filter to catch the spikes going TO the power source, which then goes into my house and works it's way into my TV??
The line terminals always go to the AC mains or wall outlet. The load terminals always go to the equipment that is being powered. Make sure the filter is rated to handle the startup current draw of the device being powered.
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post #17 of 112 Old 03-28-2015, 11:10 AM
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Quote:
Originally Posted by Nicholas Goss View Post
But do you reverse the EMI filter or not?

The EMI filter for example has load coming in one side (the power from the wall) and going to the TV on the other side. If I mount an EMI filter to the AC is it mounted the same, or in reverse? SO that Load is on the AC side going to the wall socket?

This may sound like a dumb question to someone experience with these but I am trying to understand exactly how they work. Obviously there is a capacitor etc inside to catch the voltage spikes/drops, but it seems to me they are designed to filter out the spikes coming in from the power socket so that the device (TV in the case) on the other end does not suffer from those power spikes.

So if I am to put an EMI filter on the thing thats causing the spikes, would you reverse the EMI filter to catch the spikes going TO the power source, which then goes into my house and works it's way into my TV??
Highly perceptive of you.

Yes, you need to swap the connectors when you install it in the air conditioner line.

The filter has inductors on the noisy side and capacitors on the quiet side. It definitely matters which way you orient it. When you first installed it, you put the inductors toward the noisy line (toward the AC) and the capacitors toward the quiet line (toward the TV).

You need to keep the same orientation so swap the connectors and plug it in the AC line. If that helps even more, but still is inadequate, then start thinking about building it into the AC chassis at the very end of the power cord.

You could also try clipping a large ferrite bead on the 'noisy' side of the filter to see if that helps reduce the noise even more. If still not working correctly you could try adding one to the TV power cord too if it does not have one already. Finally, you could try adding a third on the 'quiet' side of the filter, or swapping from the 'noisy' to the 'quiet' side.

It seems as if you are on the right track.
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post #18 of 112 Old 03-28-2015, 11:12 AM - Thread Starter
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Exclamation

Just to be clear.... The schematic on this says on one side "line/load" and on the other side "load/line".

Is what your saying, the terminals on the side marked line/load, goto the AC mains wall and the terminals marked load/line goto the equipment?

They don't make things easy on these schematics. I think I already have it back to front I am going to have to pull it apart and double check it now......but I am pretty sure I put the 3 terminal side marked load/line to the mains power wall on the unit I have....

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post #19 of 112 Old 03-28-2015, 11:16 AM
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Typical EMI Filters do NOT have Capacitors on one side and Inductors on the other [Capacitor are CHEAP...so might as well use them on BOTH sides for better performance at minimal additional cost]. EMI Filters are usually BALANCED Filters with Capacitors on BOTH Input and Output....and Inductors in between them....so it's SYMMETRIC...although there COULD be differences in voltage ratings between "Input" and "Output" Capacitors (although probably NOT) and esp. how the Grounds are connected, as I mentioned above:
https://www.google.com/search?q=emi+...hematic+images

It might help if you could cite a link to the specs for your particular EMI Filter....

BTW: Line/Load and Load/Line markings clearly indicate that it can be hooked up in EITHER DIRECTION....

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post #20 of 112 Old 03-28-2015, 11:20 AM - Thread Starter
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also... any idea how to work out the amps the air con is using? The specs and manual dont tell you... Or is this a contact the manufacturer thing?

Link to the air con itself.

User manual for Air Con.
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post #21 of 112 Old 03-28-2015, 11:23 AM - Thread Starter
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It might help if you could cite a link to the specs for your particular EMI Filter....

This is the link to the inline filter I am using
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post #22 of 112 Old 03-28-2015, 11:25 AM - Thread Starter
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Quote:
Originally Posted by holl_ands View Post
BTW: Line/Load and Load/Line markings clearly indicate that it can be hooked up in EITHER DIRECTION....
Well that makes a whole lot more sense. I couldn't figure out for the life of me why it was written like that. I did not think of universal direction..... Thanks for clearing up that for me... its also good to know it can go both ways then.
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post #23 of 112 Old 03-28-2015, 11:37 AM
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Another thing you might try is building a second inline filter and use one on the TV plus one on the AC. You may not get exactly double the attenuation but you will get better attenuation.

Even if the majority of the interference is coming in straight through the power line, it may also be coming in through the antenna. You still need to identify if there is a placement/orientation of AC and antenna where you maximize the gain of the signal while minimizing the gain of the noise. It may seem to work better on some days/times than others depending on the localized signal strength at your receiving antenna of the station you are watching versus the localized signal strength at your receiving antenna of the AC noise.

This placement/orientation would be much easier to do with analog signal than with digital since you could visually/audibly interpret the degree of interference directly from what you observe with your senses. It is harder to interpret with digital because all you can see is data corruption, not the noise itself. You should still be able to figure it out though if you take notes and make your changes slowly, say one change per day, to see if the number of times the surge makes your TV signal drop out (and the duration of the drop out) are affected by the changes you are making. If your TV has analog tuner built in, you might still be able to use that as your 'sniffer' although without a real signal to receive, the tuner is likely to show you strong switching noise no matter how well you filter it because there is nothing to compete with it in the tuner.

The strength of the incoming signal will play a part in the effectiveness of the filter. Try tuning in several stations, check the signal strength (hopefully your TV has a signal strength meter built in, if not you will have to guess), and use a marginal signal to evaluate the effectiveness of your filter rather than a strong signal. The better your reception through the switching transient, the more attenuation you are getting from your adjustments.
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post #24 of 112 Old 03-28-2015, 11:39 AM - Thread Starter
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I am not sure as I have not done this much, but the specs of the air con says 1400 watts. This in amps on 240 volts is 5.83 (recurring) amps.

The filter is rated to 10 amps max.

See this link.
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post #25 of 112 Old 03-28-2015, 11:46 AM - Thread Starter
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Originally Posted by CherylJosie View Post
Another thing you might try is building a second inline filter and use one on the TV plus one on the AC. You may not get exactly double the attenuation but you will get better attenuation.
Thats what I was just thinking - I am off to the electronics shop tomorrow for some more bits.

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Even if the majority of the interference is coming in straight through the power line, it may also be coming in through the antenna. You still need to identify if there is a placement/orientation of AC and antenna where you maximize the gain of the signal while minimizing the gain of the noise. It may seem to work better on some days/times than others depending on the localized signal strength at your receiving antenna of the station you are watching versus the localized signal strength at your receiving antenna of the AC noise.

This placement/orientation would be much easier to do with analog signal than with digital since you could visually/audibly interpret the degree of interference directly from what you observe with your senses. It is harder to interpret with digital because all you can see is data corruption, not the noise itself. You should still be able to figure it out though if you take notes and make your changes slowly, say one change per day, to see if the number of times the surge makes your TV signal drop out (and the duration of the drop out) are affected by the changes you are making. If your TV has analog tuner built in, you might still be able to use that as your 'sniffer' although without a real signal to receive, the tuner is likely to show you strong switching noise no matter how well you filter it because there is nothing to compete with it in the tuner.
Yes it has built in signal strength. I was playing around with moving the antenna today and checking different stations. Funny that all channels get good signal, I live very close to the stations, apart from channel 9 and ABC24. Not sure why. I have to move the antenna (rabbit ears by the way) around to find the sweet spot.

I am also going to investigate the degree of difficulty in hacking into a nearby outdoors antenna by fitting a splitter into the main line. Its very high up though so I dont know if I am going to be able to do this. Hence my rabbit ears at the moment.

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The strength of the incoming signal will play a part in the effectiveness of the filter. Try tuning in several stations, check the signal strength (hopefully your TV has a signal strength meter built in, if not you will have to guess), and use a marginal signal to evaluate the effectiveness of your filter rather than a strong signal. The better your reception through the switching transient, the more attenuation you are getting from your adjustments.
I will check.
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post #26 of 112 Old 03-28-2015, 11:47 AM - Thread Starter
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You could also try clipping a large ferrite bead on the 'noisy' side of the filter to see if that helps reduce the noise even more. If still not working correctly you could try adding one to the TV power cord too if it does not have one already. Finally, you could try adding a third on the 'quiet' side of the filter, or swapping from the 'noisy' to the 'quiet' side.
It seems as if you are on the right track.
What on earth is a ferrite? I am going to have to google that never heard of it...
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post #27 of 112 Old 03-28-2015, 11:47 AM
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Typical EMI Filters do NOT have Capacitors on one side and Inductors on the other [Capacitor are CHEAP...so might as well use them on BOTH sides for better performance at minimal additional cost]. EMI Filters are usually BALANCED Filters with Capacitors on BOTH Input and Output....and Inductors in between them....so it's SYMMETRIC...although there COULD be differences in voltage ratings between "Input" and "Output" Capacitors (although probably NOT) and esp. how the Grounds are connected, as I mentioned above:
https://www.google.com/search?q=emi+...hematic+images

It might help if you could cite a link to the specs for your particular EMI Filter....

BTW: Line/Load and Load/Line markings clearly indicate that it can be hooked up in EITHER DIRECTION....
Maybe, maybe not. Depends?

The filter has a schematic right on it. I would find it confusing (at least) if the schematic is not an accurate representation of the circuit inside.

It would not be the first time a manufacturer published misleading or inaccurate information, but until someone measures the ports with an analyzer or takes the filter apart to check, I would feel safer assuming that the schematic is accurate.

Anyway the OP can just try it both ways and see if it makes a difference. Even if it is asymmetrical there is no guarantee that the sticker with the schematic was put on in the proper orientation.
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Maybe, maybe not. Depends?

The filter has a schematic right on it. I would find it confusing (at least) if the schematic is not an accurate representation of the circuit inside.

It would not be the first time a manufacturer published misleading or inaccurate information, but until someone measures the ports with an analyzer or takes the filter apart to check, I would feel safer assuming that the schematic is accurate.

Anyway the OP can just try it both ways and see if it makes a difference. Even if it is asymmetrical there is no guarantee that the sticker with the schematic was put on in the proper orientation.
this is it with the schematic on it

* edit - this is the filter manufacturer page with schematics on it too
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post #29 of 112 Old 03-28-2015, 12:42 PM
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So it is NOT Symmetric...the difference primarily being how the (Safety? Chassis? One in the Same?) GROUND is configured. I'm no expert in how 240 VAC Grounding systems are supposed to work in Australia, although it's probably similar to North America 240 VAC systems.

I'm going to guess that the Yunpen EMI Filter is supposed to connect to the 240 VAC leads INSIDE the A/C with the third Ground Lead connected to the internal Safety Ground point (whatever Metal is found inside the A/C attached to other electrical components).....or mount it externally and connect to the A/C's 3-wire cord. Which begs the question as to how the A/C SAFETY Ground is connected to Power Mains Safety Ground. I'm going to presume that the protected device's Safety Ground point is supposed to terminate the EMI Filter's Ground wire as well as the third Safety Ground Wire coming into the device via the Electrical Cord...which would be external to the EMI device and hence isn't depicted on it's schematic.

Last edited by holl_ands; 03-28-2015 at 12:50 PM.
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post #30 of 112 Old 03-28-2015, 12:55 PM
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What on earth is a ferrite? I am going to have to google that never heard of it...
https://en.wikipedia.org/wiki/Ferrite_bead

Ferrite is a magnetic material made of crystalline iron. When placed around a wire it acts like an inductive choke.

The advantage of ferrite bead is that clipping one on a cord turns the cord into a low-pass filter system.

Ferrite is effective at very high frequencies because the parasitic components inherent in things like inductors and capacitors are minimized.

The filter you already bought seems to have no ferrite if the schematic is to be believed. Adding a bead will improve the higher frequency filtering in the region where parasitic components within your EMI filter decrease its effectiveness.

Probably you want the ferrite as close to the noise source as possible, but as in all things, the actual performance could vary in unpredictable ways depending on where it is installed. I would try putting it on the AC power cord where it exits the AC. More beads placed at more locations might or might not help even more. My TV already has a ferrite bead on the end of the power cord right where it plugs into the socket on the TV case.

It is also possible to put ferrite beads around the individual conductors of the power cord. You could try putting one small bead on each of the two non-ground wires on the side of the filter that has inductors. You should have room inside that little box you installed the filter in.

This is a real shame, your having to design your own EMI filter. These appliances should have better EMI filtering built into them, especially given that you are in an area with strong TV signal so this should be a total non-issue for you if the appliances were designed correctly in the first place.
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