Noise Cancellation Part 1

Neighbor got a new Solar Noisemaker? Background static a bit high? What happened to 75 Meters? Welcome to Summer Noise Season!

[@johnwest7993]

The Q codes were somewhat vague in definition when I learned them in 1962. Back then anything that wasn't lightning or spark-plug noise was someone talking on top of your transmission, so the vague definition worked quite well. Over the years QRM and QRN have come to be used to describe any noise created by man, and any noise created by nature, possibly because we have more control over man-made noise, but also because it is more regular, so filtering designs are typically different for each. For what it's worth I'm an Amateur Extra who has monitored my 7 mW ERP LowFer beacon on 175 kHz in serious noise of all sorts, monitoring it in the summer the entire way from Colorado to the Mississippi river. I've been fighting noise for a long time. I figure beating the noise is about half of what ham radio is all about. Thank you for your channel and this video.

[@MIKROWAVE1]

Gonna be a short hiatus on part 2 as I have a little vacation.

[@leiferickson3183]

Very interesting. Thanks for posting this and I am looking forward to part 2.

[@johnwest7993]

I see I wasn't very clear about QRM and QRN. When I was young I was taught that the M stood for Man-made noise, (from any source,) and the N stood for Natural noise, each of which had somewhat different possible fixes. It's possible to unplug your noisy SMPS, but you aren't likely to unplug a lightning storm.

[@MIKROWAVE1]

Thanks for watching. Hey I use the terms wrong regularly.

[@wesKEVQJ]

I try to educate growers and solar panel people when I talk to them about rf noise and how simple it is to fix it.

[@pharanchemie8645]

Thank you

[@ultrasoundguy1]

Great presentation! I've always felt that the advent of switching power supplies was one of the worst electrical engineering failures of our time. The technology (at least at a cost anyone would pay) doesn't yet exist to prevent them from creating massive HF hash, both radiated and conducted, although the latter is usually manageable with careful design. For example, I was very disappointed about a recent solution from TI to deal with AM band switcher interference from local supplies in a car; all they did was move the switching frequency to around 2 MHz to get the fundamental and harmonics out of this one band. I develop medical equipment (mostly the RF aspects of ultrasound machines which operate in the HF region), and it's a constant battle to deal with the garbage thrown out by both the internal supplies and poorly designed external systems. It bugs me no end that the equipment radiated emissions tests don't start until 30 MHz, so anything is allowed below that. It's true that back in the 60s the technology wasn't very sophisticated (perhaps debatable), but at least pretty much all we had to deal with in terms of human-generated QRN on the ham bands was the (nearly) coherent TV horizontal sweep hash every 15,750 Hz, so it was quiet in between them.

[@kkteutsch6416]

At 60's when I became a hf radio listener - thanks the father's transistor radio - It was possible to listen to am brodcast even during the day even a great distance, only the fading, ignition noise or clic switches I've heard that perturb, now after the majority of foreign am stations became off or turned evangelic ones, analog tube televison rans out but swtching power apliances are nothing but the worse things created... If I pretend to listen to the radio in all bands, there will be the noise, regards !

[@Steve-GM0HUU]

Yes, it is a sad situation. Copper phone lines never intended for use at RF carrying broadband Internet signals, horrible cheap switch mode PSUs by the bucket load in every home, electric motors and thermostats everywhere. Whenever I go /P, I usually find that just going a short distance from the nearest dwellings (sometime just several hundred yards/metres) is enough to reduce QRM from around S5 to near S0.

[@ultrasoundguy1]

@@kkteutsch6416 Yes, here in the US one could hear the "clear channel" AM stations late at night with a tiny radio from over a thousand miles away. Now even some of our local stations are buried under the switcher and digital system hash. Using something like the noise (really interference) cancellers Mike described helps greatly, but only if there's a single source of interference that's the problem since each source has a different phase and amplitude. At least the dominant source can be removed, but with every CFL, TV, PC, ..., packed with these switchers and digital hash generators it seems like a losing battle.

[@ultrasoundguy1]

@@Steve-GM0HUU On the one hand I'm sympathetic to the engineer of a CFL who has to design a product that sells for $1 (80 pence?) and so it has to be very simple, but I don't think there's any understanding of the damage they're doing, and at least some of the efficiency benefit isn't real. For example in any climate that requires heating of the home, the waste heat from an incandescent lamp is offset by less energy needed from the heating system. Similar to the EU lead-free initiative, perhaps what we need now is an interference-free initiative. :)

[@acestudioscouk-Ace-G0ACE]

Very interesting and I'm looking forward to part two, as I'm finally building my shack and have electrically noisy neighbours! I originally bought my home because it has a garden (yard) of 460ft, great for a Beverage and plenty of space for antenna experiments. Over the years neighbours have changed and now, next door, has a swimming pool and a few houses away are lots of solar panels. I'm anticipating problems when I'm up and running. I'm hoping part 2 will give me some solutions. I have two versions of the Star Roamer. One is a DX40 and the other unbranded and needing a new dial facia. Poor little things, I won't hurt their feelings by telling them what you inferred about their capabilities! If I'm correct, a lot of Star Roamers in the UK were sold in kit form. Best 73.

[@rfburns5601]

Thanks so much for the work you put into these videos, and for making us smarter!

[@MIKROWAVE1]

Ha! You you guys are making me smarter! Or at least trying to keep me honest! Seriously the viewers on this "beginners channel which is just supposed to be fun" are a frightening mix of true beginners and experimenters, folks re-living their early radio experiences by building stuff, famous hams and pirates, and crazy experienced self-taught and professional techs and engineers from all over the world, with enormous amounts of life work in radio and electronics.

[@mikesmuseum]

Wow, this was very informative and in depth. Thanks for going into some detail and history of noise cancellation. 👍

[@sincerelyyours7538]

Excellent timing! I just moved from a house that had residential power lines ten feet from the windows on two sides of the house. Whole bands were completely unusable for SWL purposes. I actually thought the oddly regular noise spikes were normal for those bands at my QTH. I'm now in a new house which has the power pole at the opposite corner from where I'm building my new shack. There's nothing behind me except a wide open parking lot, but nearly all my new neighbors have solar panels on their roofs. Lots of LED lights came with the house but I might be able to deal with those. Looking forward to seeing how your noise cancellation circuits work!

[@MIKROWAVE1]

Holy Noisemakers Batman!

[@Steve-GM0HUU]

Spoiling us again with another fantastic series, thank you Mike.

[@davidportch8837]

many thinks Mike... another great series in the making...

[@pd1jdw630]

On the qrm vs qrn I think he’s pretty much right on. Even though it’s now more excepted to be a qrn noise floor. But thanks very much for the explanation, I’ll be awaiting the next episode on this topic.

[@M0GLU]

Hi. Thank you for this. I'm waiting for the next episodes.

[@oilydigits]

It's not many years ago that when the subject of HF noise was discussed at my local radio club, I was often too embarrassed to admit how low mine was. How things have changed. My local qrm seems to rise on a weekly basis so the subject of this series of videos is right on the button for me. Really looking forward to part 2. 73 Steve M0KOV

[@-Todays-Tom-Sawyer-]

Looking forward to this series Mike. Frequent S9 noise floor my QTH means I can't even use my receivers. I have to use web SDR.

[@TheLightningStalker]

QRMan and QRNature? I think it's a little creepy that you knew I was tuning around top band this morning.😱

[@rfburns5601]

Man or Nature - sounds like a good delineation.

[@Steve-GM0HUU]

Yes, M for Man (or people as our species comprises man and woman) and N for Natural was what I was taught.

[@Gordonseries385]

👍

[@K1OIK]

Leaf blowers.

[@MIKROWAVE1]

Well yes, but do you have noise cancelling shortwave earphones that you wear when blowing leaves off the driveway?

[@nigelbrockwell6237]

I made a solid state Noise Canceller just over 2 years ago. I used an active antenna circuit to receive the noise. I was very surprised just how well it worked on the 160m and 80m bands. Looking forward to seeing your solid state circuits and what improvements you can make with them.

[@kkteutsch6416]

You bought the noise canceller or you scratch built it, have you a schematic diagram of it ? I click to save ones on video post but the coils don't shows sufficient details to make it...

[@nigelbrockwell6237]

@@kkteutsch6416 I found a circuit diagram on the internet then purchased the necessary parts on eBay.

[@MIKROWAVE1]

@@nigelbrockwell6237 Excellent and worthwhile! I will post schematics collected and parts lists as we go to my FB page - Mikrowave1s radio Resources Page

[@nigelbrockwell6237]

@@MIKROWAVE1 Many thanks.

[@cidcolead1115]

I include thermal noise in the receiver in QRN and agree with anything man-made as QRM intentional or not. (KI4TG)

[@wesKEVQJ]

I am trying to figure out if you could use a directional anntenna and a non to treat local signals as noise? Say so that you could hear a station behind another one on the same frequency? Or just to remove local stations to make it easier to find distant ones?

[@gunterkonig959]

Hello Mike, I am using an ANC-4 Antenna Noice Canceller for a long time, works good. The reduction is 20 to 40 dB. 73 de WJ8CY

[@MIKROWAVE1]

That is good performance!

[@BlancPatrick]

Hello ! Why the useful signal is not canceled too ? Many thanks !

[@PapasDino]

I'm using my original JPS ANC-4 dedicated to 160m and a newer Timewave for regular HF. A switch box allows me to use one of three noise antennas, two orthogonal dipoles and a shorter dipole. It's always seemed like black magic to me in adjusting these things and frankly simply turning them on results in a 3-5 dB reduction in noise (and probably a bit of signal as well so the effect is probably fooling me but it sure sounds good!). This should be an interesting project Mike! 73 - Dino KLØS

[@MIKROWAVE1]

Wow! Dino - you are a serious knob twiddler all right.

[@mauriciosinigaglia4761]

Does this tube noise canceler have any diagram or source from where you got the project? tks

[@williamrmeara2162]

Has anyone heard noise from the electric vehicle chargers that are popping up in residential areas? 73 Bill N2CQR

[@oilydigits]

I believe that it used to read, QRM Are you being interfered with? With the answers ranging from 1. nil, all the way to 5. extremely. Now in our more enlightened times the ITU says, Is my transmission being interfered with? Sounds much better, but of course it can still be very annoying. QRN seems to have changed from, Are you troubled by atmospherics? to, Are you troubled by static? Here, I think I prefer the old atmospherics to the modern statics:-) Steve M0KOV

[@K1OIK]

ANS? How come you are using a Knight receiver in the day?

[@MIKROWAVE1]

Jealous Much?

[@K1OIK]

@@MIKROWAVE1 of course, you are one of the few hams to be jealous of. Will you demonstrate these boxes>

[@alainmichaud8992]

This video can generate hours and hours of discussion. My question/comment is related to the slides around 14:46 (Weagant). What if I put two identical loops at right angle on the same pole. I guess this is what you meant, since you use the word "goniometer". I like it! For the same price, you get a directional antenna and a noise canceller. By controlling the amplitude, you change the direction, and by changing the phase you cancel the noise. Am I right? Is it that simple? I guess not?

[@MIKROWAVE1]

You are certainly right in commenting on how many ideas are out there to scratch your head on when it comes to noise. The two orientations that you describe are going to give: 1. the RDF function with a goniometer when loops are at right angles and 2. Phasing for gain or noise reduction when in line. My guess.

[@rfburns5601]

Per your chart at 9:57, S9 at 50 ohms should be -73 dbm. I decided to check out my Xeigu G90 with the TinySA spectrum analyzer. With rx @ 3.8 MHz LSB and TinySA set for 3.799 MHz, no modulation, S9 occurs at -57dbm. Likewise with rx @ 28.5 MHz USB and TinySA set for 28.501 MHz, no mod S9 still occurs at -57 dbm. I realize the TinySA is not a precision laboratory generator, but I've gotten reasonable results checking receiver sensitivity with it. A well functioning radio loses the signal at about -110 to -120 dbm. What am I doing wrong, or how am I misunderstanding the chart?

[@MIKROWAVE1]

Could be a typo -i'll check! But there is no guarantee that any radio's particular meter settings are following the reccomended values. So S-9 can be higher or lower for any radio.

[@Steve-GM0HUU]

I have read many accounts of people doing S-meter checks on transcievers and receivers and concluding that their S-meter indications are not accurate or only accurate at certain S-levels. I did find a QST review on the G90 which said it was accurate at -73dBm (didn't mention any figures and said results were in a table of in-depth results on the QST Web page which I don't have access to).

[@rfburns5601]

@@MIKROWAVE1 Did some further checking, your chart is correct, at least it agrees with Wikipedia's S meter page. Also I retested the radio with a 30 db pad inline - S9 occurs at -33 dbm. Without the pad S9 is at -57 dbm. If the input impedance of the Xeigu was 50 ohm, these figures should differ by 30 db, not 24 db. The Xeigu may have accurate S9 at 50 microvolt input, but dbm's will be different without 50 ohm input. Thanks much.

[@DE-iv8if]

8:17 Actually it is Boltzmann not Boltzman... Just saying..

[@MIKROWAVE1]

Nice!