Eliminate Your RFI - Build Your Own Mains Filter

[@M0JHN]

Your content is brilliant, I see made the cover of the RADcom congratulation on that hunt for the noise.

[@ianxfs]

Thanks for the kind words Morgan! Yes, I’m signing copies 😁

[@garyh8315]

Ian, you have a great skill in showing how to seek out problems and take measures to reduce or resolve those issues. A well described vid on the actions took and how it worked. Fantastic. Well done sir.

[@ianxfs]

Thanks Gary!

[@Jonshome337]

Hi Ian, Really enjoy your channel, you are always such a good "explainer" of your content. Please keep your videos coming hugely enjoyable! I have ordered the parts for this today !

[@ianxfs]

Thanks for that 👍🏻

[@James_Bowie]

Excellent project. 👍 Looking forward to Part 2 as regards those remaining troublesome bands.

[@ianxfs]

Thanks James!

[@norrinradd8952]

Very useful project, I might give it a try. Thanks for the video, well done.

[@ianxfs]

Thanks!

[@ianwhite659]

Nice work, Ian! Thanks also for the tip that it may be useful to turn the whole filter around. Yes, it's an excellent project for a club - first to have a ready-built filter available for loan, so people can find out if they need one, and then to organise bulk buys for the parts. 73 from Ian GM3SEK

[@ianxfs]

Thanks for the design Ian! 👍🏻 I’ve tried additional ferrites at either end and not really improved 6m. I’ve got a further tweak to try to improve it, just need to get round to it 😀

[@Ei2iP]

First thing I did with new shack, I built two of these...and they work, no brainer.

[@ianxfs]

Great Robbie! I have no issues at home thankfully 😀

[@zaperfan]

Great work, I have got all the parts to make this filter from Farnell. Arrived while I was watching your video :)

[@ianxfs]

Good luck! 👍🏻

[@BritishBeachcomber]

I was going to say, the filter needs to go close to the generator so you don't get EMI in the car. But you worked it out.

[@ianxfs]

Thanks yes Peter. 👍🏻

[@matknight]

A result which ever way you look at it Ian, ive bookmarked this video and will attempt to build my own once my confidence peaks. 73.

[@ianxfs]

Good one Mat!

[@WireWeHere]

6:40 A pencil adds a nice touch as a threading tool when taped smoothly to finish your pointy tip with a sharp pointy tip.

[@ianxfs]

Thanks.

[@markg6jvy135]

Nice build Ian, thanks 🙏 Celeb on the magazines now too…well deserved😉 👍👏👏

[@ianxfs]

Ha ha yes Mark 😁

[@wildweasel6898]

Very cool brother. Thanks from a new ham across the pond 🤠

[@ianxfs]

Thanks!

[@vincei4252]

Thanks! I have all the bits to build Ian's filter. Lol, Mouser here in the states never offers free postage. They have on occasion upgraded me to next day from Texas to Connecticut when they fail to get the order out in a timely fashion.

[@ianxfs]

Thanks Vince. Yes, ours comes from Texas too! Over £30 and p&p is free. It’s a pain though when you just want one small item 🙄

[@vincei4252]

@@ianxfs Wow, I didn't realise they shipped from Texas to the UK. Free shipping is the only thing that would make it viable for smaller orders.

[@joeblow8593]

Very good , cheers from the U.S.

[@ianxfs]

Thanks Joe 👍🏻

[@Jonshome337]

Hi Ian ok on 40M dropped from a S9 to a S5 AND 20M Dropped from S9 to S5. Thanks for the great video once again ! 17M S9 to S3

[@ianxfs]

Great. Well done! 👍🏻

[@MM0OPXFieldRadio]

Nice practical demonstration Ian. I'm a big fan of GM3SEK chokes and made a few myself. I run a Honda/Haverhill 2.3kva generator, no noise on HF but its a brute compared to yours.

[@ianxfs]

Good one! 😀

[@M7BCN]

Great video Ian.

[@ianxfs]

Thanks!

[@kevinkc3onohelijeepworld953]

Nice filtering. I m getting noise the other way from my 10kw gener ac sadly where it’s positioned atm my balanced feed goes 30’ over genie and over to my feedpoint mast and then my hw dipole element is 80’ higher, so I pick up the noise by my antenna. Hope to build a dog house to put genie in away from my feeder and element. I wonder if any of the noise/ harmonics were cause by the stepped sine-wave inverter inside the genie ??

[@ianxfs]

Yes it will be the inverter inside. A wire mesh faraday cage is another option if it’s radiating….

[@TS950SDX]

Watched your video great stuff. Just cured the same problem using 15 clip on ferrites on the mains power lead for the shack. Cheers GM0EEH

[@ianxfs]

Great James. Glad you’re sorted 👍🏻

[@TS950SDX]

It took two years and a bucket of ferrite but i can now hear everything under an S9 on full hf scope virtually no noise. So pleased.

[@acestudioscouk-Ace-G0ACE]

Another interesting video Ian, thanks! Is it possible to work out before, which frequency the chokes and filter will hit? I was wondering if you could build different units for given bands or build the chokes as a type of module for a band.

[@ianxfs]

Thanks. Yes, I know what you mean, but I suspect that’s not within the scope of an amateur or the equipment we have access to. A good wide-frequency choke like this one does the business, but just starts to struggle at 50MHz, which to be fair is a long way up the spectrum from HF. I’m still working on this, so hopefully will be back with an update 👍🏻

[@acestudioscouk-Ace-G0ACE]

@@ianxfs Thanks for the reply Ian, I take your point and look forward to updates. Keep up the good work!

[@davidenglund]

Good video. Thanks! What kind of pole are you using in those mobile pictures? Thx

[@ianxfs]

Thanks David. I don’t know….it was a second-hand bargain at the club….

[@alistercarmichael4990]

A couple of points for safety. They may be covered elsewhere in the comments. Portable generators should have an earth at the generator as the origin node. This is always the case. In the event of device (load) failure you will need that protective conductor working. I strongly suggest an RCD on the output and said earth. Normally this is a spike driven into the ground below ground level (as the surface would become live in fault conditions). Your RCD would cut current in any event and also permit a far poorer earth to be operational. Always beware of underground hazards though when driving conductive rods into unknown ground. Those were common mode chokes. All conductors passing through the same core. The idea being that current going up rather than round is dumped into the ferrite. Placing the earth in there too prevents it from draining this bad energy to where it should be going. That would be the true earth that you installed with the generator. The protective conductor should not be in the filter circuit and should always have as direct and low impedance path back to a nodal origin as possible. Earth noise should be eliminated by correct nodal wiring and never by filtering the earth. Great examples of earth noise being Hifi setups and amplifiers where the signal lines circulate mains earth via shields and introduce hum. If there was adequate earth on each box there would be no current through the shields. Please research though as this is the last line of defence for faults and small mistakes can cost lives or at the least blow sensitive equipment. Excellent videos through. Inspiring me to track down an endemic 2M broadband QRM.

[@ianxfs]

Thanks for all that info Alister. I will follow up.

[@pametnaradionica]

Alister is right here! There you have a HF source of noise and you`ve ran ground wire through a choke. So, what you should do is: Unwind the ground wire from the choke, it introduces impedance there. Make a separate bolt to the outside of the box and make it easy to connect an outside ground wire with a good steel spike at the other end and bring a hammer. The name says it all "ground" should be grounded. this way it just floats around not doing it`s job. I don`t believe it would burn your radio but you`ll get much less noise. It will increase your radiating power too. Or, forget this all, if you are grounded through your antenna. Then your system is grounded and you should not be sticking anything more in the ground. You need just one ground point in the system. More than that and you`ll introduce noise. Best of luck.

[@M0XXQ]

Hi Ian, I have this issue on a Champion 2KW genset and have already made one of these a few years ago for another application, I'm trying to locate it so I can use it when out /P up on the Weardale fells. Luckily it doesn't creep up to 70 or 144MHz as I use these bands for Meteor Scatter, however 28Mhz and 50Mhz was unusable with the generator running so I invested in another 100AH battery as I tend to do overnight stays at my portable sites in IO85 and IO84 so having the generator there as a backup is a must. I've earthed the genset to the Van chassis and hopefully I will find the filter unit tomorrow as I'm out over the weekend and would love to be able to run the generator, as low noise as battery ops is the runtime is pretty restricted. Cheers Rob M0XXQ

[@ianxfs]

Good luck Bob 👍🏻I was thinking about an earth test too, with a copper rod 🤔

[@M0XXQ]

@@ianxfs I'll give it bash tomorrow and let you know the result as I'm out overnight /P for the Meteor Shower.

[@timg5tm941]

Superb video Ian 73

[@ianxfs]

Thanks Tim!

[@kerkoules]

Hi Ian, what is this plastic looking screw you have used to secure the schaffner on the box please? does it have a lock nut on the outer side of the box? Thanks

[@ianxfs]

Yes they’re plastic bolts with nuts and washers. You can get them online if not local. Thanks for commenting and good luck 👍🏻

[@2metercrew389]

That’s a great idea I never thought about running a generator I will have to look into that👍 by the way what was the issue with the electrical system on the vehicle???

[@ianxfs]

Hi and thanks. I had voltage drop due to heavy current draw on one setup. And an issue with not presenting 13.8v on another. Both worked, but noticed a reduction in power and on vhf/uhf ever watt counts 👍🏻Main leisure battery now two years old, so mulled over my options …..

[@2metercrew389]

@@ianxfs Oh yes I know exactly what you mean. I had to rewire my whole electrical system with zero gauge wire with an upgraded alternator with all interconnections to and from the alternator being zero gauge with a second battery in the back.

[@johng7rwf419]

Very good, thank you.

[@ianxfs]

Thanks John!

[@johnratcliffe6438]

Hello Ian, were those before and after shots take when connected to your generator or mains? I tried running my FT891 on battery power at home this morning to see if I could identify noise that has plagued my FTDX5000MP recently (S7 on 20m-6m). My noise floor was lower today ay S5 pre-test, but only fell to 1-2 S points on battery power with the mains totally disabled. Only thing still powered was standby battery for our home alarm. Just curious whether you think it's worth my while building one of these? I suspect the QRM is generated from the homes around me. 73, John (2E0SVB).

[@ianxfs]

Hi John. Yes the shots were in the genny, with/without filter. If you’re noise reduced by going on battery and you’d done a mains test on the same rig before, then yes I would say the filter is worth a try as it sounds like some of the noise is on the mains somehow? My mains supply is ok and the general noise is from the residential area around me. Good luck! ps. Do you mean “fell by” or “fell to” when referring to noise levels?

[@johnratcliffe6438]

@@ianxfs So sorry Ian, I meant fell by. Was S3-4 on battery power. Thank you!

[@pauls9440]

Ian did you earth the generator with a ground stake in the before or after tests?

[@ianxfs]

Hi Paul. No, I didn’t use the earth. Floating earth seems to be the way to go with these generators and the ground lug shouldn’t make a difference. I could do some tests. Ongoing project this one. Been trying others things….

[@vincei4252]

Does the generator have a grounding lug? If it does (my Yamaha did) try sticking a spike in the ground and tying the generator to that to see if it helps.

[@ianxfs]

Thanks and yes it does Vince. After a lot of reading I decided to leave it as a floating earth and not attempt to ground.

[@James_Bowie]

That generator ground is to provide safety for any (metal) tools or appliances with a ground pin connection. However, it's not going to be safe unless the ground connection is a very good one. Good RF grounding requires flat strap or braid.

[@architetturaearte]

Well done! But if I see the design of gm3sek the LOAD and LINE not are the same of the your project. Why? Many thanks

[@ianxfs]

Not all filters are the same. I’ve fed back to GM3SEK. Best to check the spec of the filter you’ve purchased before wiring. Good luck 👍🏻

[@itsonlyme9938]

I have had installed a electric smart meter for my electric supply and putting a MW radio next to it the noise pick up hi very bad and even place it next to, the house wiring the noise is bad. I have the parts for this filter and I am going to see if the filtered mains if there is any noise coming out of the filter using the portable MW radio .

[@ianxfs]

Ok. Good luck. Maybe contact the installer about the issue?

[@itsonlyme9938]

@@ianxfs The smart meter is computer controlled and it uses I suspect a switch mode PSU. Built the filter and listening to my radio no major difference . I have built a copy of the Wellbrook loop which helps a lot its ok for reception around Europe but not low angle stuff. The noise has dropped from S9+ to about S6 on 40m. it has a very sharp null on near by switch mode PSU almost taking it out.

[@vincenzofidanza2539]

Likely for 6 meters you need a ferrite like mix 61 to add to your array to increase high frequency attenuation

[@ianxfs]

Yes a better mix for 6 👍🏻

[@russozard2626]

interesting project ian I've been meaning to ask what mobile tower you are using when portable

[@ianxfs]

Hi Russ. It was a second-hand bargain at the local club. Unbranded I’m afraid, so I have no idea…sorry.

[@geirha75]

Does the wiring around the cores get warm?

[@ianxfs]

It shouldn’t do as it’s all rated to comply with the normal wire/fuse rating. I wouldn’t be touching anything inside of the box when it’s live. Thanks.

[@patrickh9679]

Thanks for your great video. I have built your filter with the same components and saw a good improvement. My problem is that my high end PC is working perfectly at night while getting slow and sluggish at daytime which is a big problem for competetive gaming (even offline on Desktop). It happens from grid and from a power station disconnected from grid, the Filter improves both, but I can not measure it. My question is with which device and accessories I can troubleshoot this problem as cheap as possible? It is hard to find information as a noob. Any hint would be appreciated. Thank you

[@ianxfs]

Sorry to hear you’re still struggling. I’m afraid I’m not aware of a means of measuring in the way you suggest. Apologies if you’ve already considered this, but I wonder if you’re actually competing with other households sharing the same ISP local infrastructure and that’s why you see marked differences between day & night internet performance? Good luck getting sorted 👍🏻

[@patrickh9679]

​@@ianxfsthank you for your answer. As the problem persists offline when the pc is not connected to the Internet, but your filter improves it, I suspect EMI/RFI. So I would like to know which device I need to troubleshoot or how to even start. Spectrum analyzer? I looked at the model "TinySa Ultra". This offline day/night difference is a widespread problem in the competetive gaming scene without any real findings yet. People trying many PC builds and different locations, until they sometimes find a "good" location by luck. So the problem is definetly something about the Location. The main symptoms are: -delay of input until visual response -degraded visual quality of the monitor -.. Which improves much at night. I understand if that is the wrong platform to ask this but gamers are no RFI Specialists and I was trying to get any hint😅 Thanks

[@ianxfs]

@@patrickh9679 Ok Patrick. An easy electronics way to test is to run the PC on battery power. Either through a suitable inverter to provide mains voltage from a suitably sized battery, or with the right know-how, tap into the DC side of the PC power supply when not connected to the mains and provide the equivalent DC volts & amps ie pure battery power. THE IMPORTANT PART: A qualified electrician or electronics engineer needs to do this, to avoid all the obvious safety risks to the person undertaking the work, plus avoiding the damage risk to the PC. Good luck.

[@patrickh9679]

@@ianxfs understood, thanks. Maybe my first post was confusing. I tried run pc offgrid from: a)bought 2000wh pure sine wave power station b) car battery + pure sine wave inverter nothing changed it is even slightly (constant) worse. Thats why I thought the problem is rfi and I wanted to check it. Still this mains filter improves the situation for power station and ongrid. I have not enough know how why this could be. The direct supply of dc is interesting, thank you.

[@tomnorman5461]

I'm not 100% sure on this; but I don't think you need to "wind" the ground wire in the cores. The ground wire is strictly for safety and not a "current carrying conductor". If you were to omit the ground wire in your winding's you may be able to get an few extra turns...Might help?

[@ianxfs]

Thanks Tom! Coincidentally, I contacted Mouser tech support (as it was from them I purchased the components from) and they also suggested rerouting the ground. That’s my next step on this project, just haven’t got round to it yet, as been running the noisy 6m band o the big battery when /P. Thanks for the suggestion 👍🏻

[@dvhammer]

You need to include the ground wire in the ferrite core winding to have the common mode choke be functional. The ground wire carries common mode current. Please refer to K9YC (Jim Brown) papers on this subject.

[@johnratcliffe6438]

Is this worth trying for the shack at home Ian? I have had S7+ of noise on some bands at Christmas... 73, John 2E0SVB

[@ianxfs]

Hi John. The original design was actually meant for home mains use. However, try running on a battery first as that will confirm whether your RFI is mains borne or not. If the noise goes/reduces on battery, then worth going down the filter route. Good luck 👍🏻

[@johnratcliffe6438]

@@ianxfs I bought an FTDX5000MP which is mains only I think Ian. I can run my FT891 on 12v though, so will give it a go at the weekend. I hope you're well, Happy New Year!

[@ianxfs]

@@johnratcliffe6438 Ah yes, you’ll have to use the 891, assuming it gets the same issues? All good this end John and a Happy New Year to you and yours too 👍🏻

[@JohnStruemph]

Well done! Thanks for sharing. 73

[@ianxfs]

Thanks John!

[@JohnStruemph]

@@ianxfs you are very welcome! That is a well done handy video.

[@trig6712]

Good Many thanks

[@ianxfs]

No problem.

[@wfqka]

what u think of using battery generator and using isolation transformer to charge the batteries with that power the equipment only from the generator battery will it reduce rfi?

[@ianxfs]

Hi Daniel. I think I know what you mean. Generator>filter>battery charger>battery. They’ll all still be connected, so the issue will be the same I think? Plus, making sure the load doesn’t get applied to the charger. I’ve got a couple of ideas to try to improve the performance on 6m, so hopefully will be able to report back 🤞🏻

[@wfqka]

@@ianxfs sorry if u dont understand me i was thinking charge the batteries with isolation transformer then using them with the equipment

[@wfqka]

I will use the equipment only from the generator

[@ianxfs]

@@wfqka Ah ok. I’m using the generator because the two amplifiers (2/70) are happier at 13.5v+. Plus the rig on its own on 6m is pulling a lot of current at 100W and causing some voltage drop.

[@mikesmithg0rfd356]

thank you

[@ianxfs]

No problem Mike!

[@pcmultimedia1]

With my horrible QRM on hf coming from my inverters , I’ve ordered in these filters and ferrite , enough to build two of these filters , I’ve got a 15amp 230 and a 25amp version , This QRM off the inverters is a real problem , I’ve proved it coming from the pair of inverters , even switching the load to the house off, there is still QRM from them , I think it’s going to be a challenge to cute this QRM for sure.

[@ianxfs]

Good luck 🤞🏻

[@michealbell5042]

Will this technique work with a 12v to 240v 50 hertz sign wave inverter?

[@ianxfs]

Hard to say Michael. I have had success with a generator but never quite sorted 6m inverter interference. I use a battery and inverter on 6 for occasional rotator use (due to the interference), but not tried the filter inline with this setup. I might give it a try to see 🤔

[@ianxfs]

If I remember Michael, I’ll be able to try this Thursday on the 6m UKAC. Just depends if the interference is cable or air-bound…

[@michealbell5042]

Ok cool. Thanks for replying, if you get the chance to do a video I will watch. But if not I'll have to experiment and see for myself. Thanks for the video 73's 👍

[@ianxfs]

@@michealbell5042I tried it last night Michael and it didn’t work on 6m. I know it does work on the generator on 2m & 70cm, but I use battery & inverter on 6m because I can’t filter all of the generator inverter on that band. The battery inverter must have the same issues….

[@michealbell5042]

@@ianxfs Thanks for trying. I guess that's where we have to experiment with it. Hay but you konw what you still did grate video and thanks again for replying. 73 and merry Christmas .

[@paulhg1ztn]

Hi ian I don’t know if been said already in the comments but try a different ferrite mix perhaps a type 61 mix as there’s is different choke impedance at different freq

[@ianxfs]

Hi Paul, yes other mixes to try, plus number of turns etc. Nothing at home to add in so will tweak before more purchases….👍🏻

[@kaybhee6]

goot... doing very similar stuff w tdk,, and other parts... i might need earth,, and shield tho

[@ianxfs]

Good luck 👍🏻

[@dancosminmarza2974]

hi for the 6 m and above usualy you need a linear suply hevyly filterd vith lots of small electrolitic and rfy caps and power cable 4 the radio shielded and choks on the leeds 4 me it helpes maby it whill 4 you 2 73

[@ianxfs]

Thanks for the info 👍🏻

[@apglass2154]

One problem I see is you have no ground rod connected to the generator which alleviates static build up. Look at the front panel that generator there should be a systematic for ground with a tap screw on it

[@ianxfs]

Hi. Yes, you’re right, but after a lot of reading I’ve gone for a floating ground, both for safety and RFI.

[@apglass2154]

@@ianxfs how much dissipation can be achieved with a floating ground I've never looked into it

[@ianxfs]

The ground seems to do little for RFI reduction and giving a ground to a vehicle and circuits which aren’t grounded adds an element of risk to the occupants. Also, achieving a good effective ground over and over again on a portable site is difficult to achieve in reality.

[@andythebrave]

use glue gun to secure ferrite

[@ianxfs]

Thanks Andrew.

[@macdee8628]

Another great vid Ian de 2e0utb

[@ianxfs]

Thanks Mick!