Successfully Hunting Down QRM With A New Loop
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- Опубліковано 27 лип 2024
- Having not been on the HF bands for a month or so I was horrified to find a whole load of new QRM across 160m, 80m and 40m. Time to break out my direction finding loop that I'd used successfully before (see video link below). However, I was struggling to make progress and then I remembered a past suggestion for a revised, more sensitive, loop design. See how I get on and what I discover...
My thanks to The Radio Amateur Society of Australia Inc. for the original loop design and additional thanks to Don (WD8DSB) for his suggestion for this revised design (also thanks to the person who suggested a solder-only method of construction for the original loop - unfortunately, I've lost that email).
A link to the start of a series of three QRM hunting videos, including the build of the original loop, complete with sniffer-wand, can be found here: • A Rare Local Area Powe...
This is one of many amateur/ham radio related videos on my channel. Please feel free to browse 👀, like 👍🏻 and subscribe (it's free!), remembering to hit the bell 🔔 so you’re notified of new videos as soon as they're published and you don't miss out.
0:00 QRM Intro
2:38 Power-Off Test
3:23 Loop Designs
5:40 Loop Build
14:12 Initial Tests & Search
17:51 Search Results
19:18 Seeking Help
19:59 QRM Source Found
20:50 QRM Gone
Thanks.
Ian. - Наука та технологія
Thanx for video Ian. Made exactly the same loop and hunting for very annoying qrm in my hood. To disguise the loop I used tennis racket sleeve which fits perfectly.
Placed a little receiver and antenna into the backpack and off I go. Riding a bike around the neighborhood and found a house in front of which my receiver went nuts. Next step is trying to talk to the owner. Thank again and 73 de Mirza K9IG.
Brilliant! I like the racquet cover idea 😁👍🏻 Good luck on sorting it out 🤞🏻
Well done Ian. You are very lucky with your neighbours. Mine refused to cooperate with OFCOM because they hate my mast and antennas, so nothing was done.
What a pain John, sorry to hear about that 👎🏻
Thank you Ian! Your video has really reinforced my work on a mag loop project. My initial motivations for a mag loop were that they are compact and, with a high Q, help eliminate QRM and QRN off frequency. Your video illustrates the other great feature of loops, the strong null that is perpendicular to the loop itself, allowing for direction finding. I'm doing a deep dive on mag loops for both reception and transmission, one loop covering 30-10 meters, the second much larger one covering 80-40. I hope to have something published in another month or two. Again, thanks for adding to my overall understanding the value behind loop antennas!!
That’s great! Good luck with your projects 👍🏻
I do like watching your videos, always something different and well explained.
I do like the QRN from the blackbird in your garden 😊
Thanks! Ha, ha yes, sometimes the phone picks up the birds quite loud! Deep in my video list there’s a tour round the garden (to help those stuck at home with lockdown and no garden)…lots of birdsong on there 😁
And yet another top notch well presented video Ian 👏👏👏
Hey, thanks John 😀
I'm using these days a chinese Malahite clone as a portable radio. Much more portable than a 100W rig and a heavy battery pack. Will less than 200 USD it also doesn't break the bank.
Thanks for the tip 👍🏻
I actually made the original loop from the first video, but wired it straight through and bit shorter on the left side. Then I made a couple of swappable pieces out of RG59 about an inch long one with the conductor and insulator connected and one with just the insulator connected. With this I can swap between them to increase/decrease sensitivity as required. Anyway, thanks for the video and nice chatting with you on the air 2E0HZA.
Great stuff Adrian. Thanks 👍🏻
Nice one Ian, I may have a go at building one myself.
Definitely an asset Stu if you’re suffering 👍🏻
Well done Ian 👍🏻
Thanks!
Great video... Just a quick thought for the mechanical/solder connection between the end back onto the main coax sleeve.. instead of soldering a big fat finger end with the centre connecting inside then needing big heat to get that to solder to the main braid you could solder the end short but leave 6" of bare inner projecting out then wrap 2 turns of this around the main coax braid then wrap anything left back around the end finger short. Mechanical strength from the copper not the solder & not needing as big an iron to heat the joint.
Yes, thanks for that 👍🏻
Great to work you the other day from the Isle of Sheppey with GB0SB, great video buddy love these ones :)
Brilliant! Yes, great to get the SES in the log, thanks 👍🏻
Nice job It brings back memories of wen myself and Carl went on a hunt to find the source of a wide band signal that completely wiped out HF . Like yourself it was in an adjacent street at the rear os my property. The owner was willing to help and we found it to be a transformer for a led light strip imported from China for £3. Oh the joy of silence 👍
Hi Paul. Yes it’s just all a right pain isn’t it 🙄
Hi Ian,
Glad you were able to track down that car battery maintainer as the noise source. You're getting to be quite a sleuth. 🙂 Stay safe. 73 WJ3U
Yes Don. Glad it’s sorted 👍🏻
Good job!
Thanks!
Outstanding work Ian and great video 👍
Great and thanks 😀
Hey mum there is a strange man with a backpack and a bum bag with some strange circle thing in his hand walking up and down our road and standing in our front garden. Love come away from the window.
Great video Ian nice work.
Motters M7TRS 73 👍🏽
Ha ha Lee, yes, it does feel a bit like that at times 😁
@@ianxfs Ian mate fantastic work and good on you making and going out to find the noise. Feels like a life time since I've been out with the 817. Just in the process of making a loaded coil vertical for portable work. The issue I have when doing sota is the foot print needed for a dipole or efhw. We have to try these things. 👍🏽
@@m7trsradioHave fun Lee!
Really useful Ian may thanks
Thanks Tom! 👍🏻
Nice video and well done
Thanks!
Great work Ian 👏 👍
That was quick! Thanks Andy 👍🏻
@@ianxfs love the way you show us everything on your videos and not just skip through bits.enjoyed it mate thankyou
Wish my identified QRM would go, It flattens 80mtrs S9 +10db and 40mtrs S9 then tails off up the bands. I built a loop and found it was the shop next door but one, LED lighting presumably being run from a cheap switch mode PSU. did try speaking to the shop owner, but he got rather abusive and told me to F... off. so thats my operating curtailed somewhat, thanks to the local Premier shop.
Not good. Perhaps a letter/email to head-office and explain the situation and see if they can step in? Hope you get sorted...
Hi Ian, Great job and glad the traditional loop I suggested worked well for you. Tracking down RFI is a never ending job. 73, Don wd8dsb
Great and thanks again Don! 😀 Just 40m to sort now 🙄
Excellent video very informative compared to other videos ive seen. How can i adapt this to 11 meter?
Thanks. It will be fine on 11m. If you watch the original loop design video on the channel, that may be more sensitive on the higher frequencies. Good luck 👍🏻
Save yourself the time, get a good portable AM radio (MW) tune to an empty spot and start waking and turning your radio, works every time. short cuts of an old timer.
Hi Joe and thanks for the tip. Yes, I tried that with a little tranny, but no joy. The better radios aren’t cheap, so this was my best option as it cost nothing. Thanks again 👍🏻
@@ianxfs No cost is great option, just remeber that one can get a good old sensitive MW/AM portable radio at any good op-shop for about $5
Have you tried a QRM Eliminator ?
Hi, no I haven’t. Fortunately, I’ve managed to find sources so far and remove them. 🤞🏻
@@ianxfs Your very lucky to have understanding neighbours ,
I made your first loop last year as I had problems but mine is intermittent so hard to catch , I've purchased a QRM Eliminator after watch many videos on youtube
Is there any reason why I couldn’t use RG eight instead of RG213?
Should work. Velocity factor the same so they match on that front. Worth a try for no cost. Good luck 👍🏻
Since the antenna is not being constructed for a specific frequency I really think the VF won’t play a major role. I’m definitely going to do some music if you types of coax
Which car charger do you recommend for no QRN?
Hi Gordon. I use a Maypole charger and that’s also what I bought for the previous neighbour. Made in England 🏴 👍🏻
@@ianxfs Thanks, I will bear that in mind. Car batteries don't charge properly these days in the car. More and more people are using conditioner/chargers.
Excellent video and well done on tracking it down , I have something similar where I live it's hurrendous
Tony M0VDO
Thanks Tony. Good luck if you have a go at sussing yours 👍🏻