Amazing Results With QRM Eliminator

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Buick Mackane
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Amazing Results With QRM Eliminator

Post by Buick Mackane »

Bought an Xphase QRM eliminator a few months ago which i briefly tried on eleven metres with mediocre results, But the noise antenna i was using was just a small indoor magmount. Anyhow iv'e just recently got setup on HF and was getting hammered with S-8 of noise, So i thought time to try the xphase again, But this time i'm using a different noise antenna, The cable that feeds power to my garden shed, Just stuck a croc clip on the plug earth pin, And christ almighty :shock: The noise has dropped by at least 80% Think its because the power cable is close to the noise source, So if you've any doubts as to whether these things work or not i can assure you they work like a miracle, Its just a case of finding the right noise antenna and getting it as close to the noise source as you can, But once you get it setup up right you'll be amazed..
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Re: Amazing Results With QRM Eliminator

Post by ghost123uk »

So do you mean you are using the earth wire of the cable that feeds the shack as the noise aerial?

If "yes", then I note you clipped it on via the earth pin of the plug. I then deduce that the cable is not live and powering anything in the shack at that time. I then deduce that the QRM drop might be because the cable, or summat running off it, was causing the QRM ;)







p.s. = only joking, I know you well enough from your posts to know it won't be that ^^^ (will it? :lol: )
John, on the S. Cheshire / N. Shropshire border. 26TM953 / muppet handle "Grey ghost"
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Re: Amazing Results With QRM Eliminator

Post by Classic »

Buick Mackane wrote:Bought an Xphase QRM eliminator a few months ago which i briefly tried on eleven metres with mediocre results, But the noise antenna i was using was just a small indoor magmount. Anyhow iv'e just recently got setup on HF and was getting hammered with S-8 of noise, So i thought time to try the xphase again, But this time i'm using a different noise antenna, The cable that feeds power to my garden shed, Just stuck a croc clip on the plug earth pin, And christ almighty :shock: The noise has dropped by at least 80% Think its because the power cable is close to the noise source, So if you've any doubts as to whether these things work or not i can assure you they work like a miracle, Its just a case of finding the right noise antenna and getting it as close to the noise source as you can, But once you get it setup up right you'll be amazed..
I've got one here but can't seem to get the result you got. Mine seems to work in reverse,it knocks the wanted signal away and makes the noise stronger.
I was trying it on am with different antenna setups and did have some good results.But on CB not good.
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Re: Amazing Results With QRM Eliminator

Post by Buick Mackane »

Classic wrote:
I've got one here but can't seem to get the result you got. Mine seems to work in reverse,it knocks the wanted signal away and makes the noise stronger.
I was trying it on am with different antenna setups and did have some good results.But on CB not good.
Probably because the noise antenna is receiving the wanted signal and nulling it. Trick is to receive the noise and the noise only. Easier said than done. The noise antenna shouldn't be resonant on the band your using, For example if your using it on 11m then you don't want to use a noise antenna thats resonant on that band otherwise it'll pick up the wanted signal and attenuate it. If you know the exact source of the QRM try and get the noise antenna as close as possible to it.
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Re: Amazing Results With QRM Eliminator

Post by Buick Mackane »

For anybody thats interested i bought mine on ebay from a guy in poland. Its all he sells. Presume he builds them from kits or homebrews them. They're pretty well made, They usually go for around £40 quid. Don't go buying the wimo version for around £160 quid, They both use the same circuit.

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Re: Amazing Results With QRM Eliminator

Post by porky.69 »

very interested ....im fed up of qrm. il try it for £40 notes 8)

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Re: Amazing Results With QRM Eliminator

Post by johnkyrle »

Confused here.I suffer with major QRM issues as I have detailed here before.BUT,you need another antenna to attract the QRM I take it?You mention it needs to be tuned to,obviously,a different band.How is this achieved?Surely if QRM is present all across 11 meters then how can it be possible to draw that away from the main antenna?
So the QRM we are experiencing is really a second or third harmonic of 11 metres?If that is the case,I would not want to be operating on anywhere near 40-20 metres at the time.
Please explain :wtf:
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Re: Amazing Results With QRM Eliminator

Post by Buick Mackane »

johnkyrle wrote:Confused here.I suffer with major QRM issues as I have detailed here before.BUT,you need another antenna to attract the QRM I take it?You mention it needs to be tuned to,obviously,a different band.How is this achieved?Surely if QRM is present all across 11 meters then how can it be possible to draw that away from the main antenna?
So the QRM we are experiencing is really a second or third harmonic of 11 metres?If that is the case,I would not want to be operating on anywhere near 40-20 metres at the time.
Please explain :wtf:

I'm no expert. But yeah you need an aux (noise antenna) to receive the QRM, Theory is the QRM received by the aux antenna and the QRM received by the main antenna will be out of phase with each other and will be cancelled out. And yeah its probably a harmonic of some other frequency, I get it all across HF.

If you use a noise antenna thats resonant on the band you want to work then theres a good chance it also will receive the wanted signal and cancel it, If the noise is local as in from a neighbours house then any random piece of wire should pick it up. In my case i know exactly where the noise is coming from and i'm able to place a noise antenna about ten feet from it,
Rough diagram of how it works

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Re: Amazing Results With QRM Eliminator

Post by ghost123uk »

It's the same principle as noise cancelling headphones.
John, on the S. Cheshire / N. Shropshire border. 26TM953 / muppet handle "Grey ghost"
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Re: Amazing Results With QRM Eliminator

Post by Admiral »

And microphones
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Re: Amazing Results With QRM Eliminator

Post by Classic »

My pc causes 5+ of noise and i've tried tiny bit of wire right next to it and still can't null it out.
Classic

Re: Amazing Results With QRM Eliminator

Post by Classic »

Buick Mackane wrote:For anybody thats interested i bought mine on ebay from a guy in poland. Its all he sells. Presume he builds them from kits or homebrews them. They're pretty well made, They usually go for around £40 quid. Don't go buying the wimo version for around £160 quid, They both use the same circuit.

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Hi mate you know the antenna gain knob does that play a part ? What does it do ?
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Re: Amazing Results With QRM Eliminator

Post by ghost123uk »

Classic wrote:Hi mate you know the antenna gain knob does that play a part ? What does it do ?
It's function is as follows :-

Imagine 2 sine waves that are 180 degrees out of phase, but one of them is of a much higher amplitude than the other. The "product" of these two out of phase waves will produce an output. However, if you can either boost or cut the amplitude of one of them, so that they are then of exactly the same amplitude, then, as they are 180 degrees out of phase, the resultant output is = zero. This is why there are controls to alter the amplitude of the signal from the "noise" antenna.

In the real world though, we are not talking about simple sine waves. Getting what we do have (qrm) to be 180 degrees out of phase, AND of the same amplitude is not 100% achievable, so the output can never be perfectly nulled, just as good as can be got, which in turn varies due to many factors, such as the nature of the QRM, the placement of the noise aerial etc etc.
Last edited by ghost123uk on 09 Feb 2017, 12:35, edited 1 time in total.
John, on the S. Cheshire / N. Shropshire border. 26TM953 / muppet handle "Grey ghost"
Don't just monitor, key up and talk, otherwise everyone thinks no one else is out there !!!
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Re: Amazing Results With QRM Eliminator

Post by ghost123uk »

Classic wrote:My pc causes 5+ of noise and i've tried tiny bit of wire right next to it and still can't null it out.
Try it with the monitor turned off. Let me know if it still does it. There may be a solution.
John, on the S. Cheshire / N. Shropshire border. 26TM953 / muppet handle "Grey ghost"
Don't just monitor, key up and talk, otherwise everyone thinks no one else is out there !!!
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Re: Amazing Results With QRM Eliminator

Post by Admiral »

Classic wrote:My pc causes 5+ of noise and i've tried tiny bit of wire right next to it and still can't null it out.
Probably the two Dollar Chinese power brick
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