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| ScarboroughSeadog Member Since: 21 Jul 2022 Location: Scarborough Posts: 110   
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Just fitted a double C/single USB charger in place of the fag lighter, and piggy backed a single C plug installed in the dash top (wired to a magnetic charger dock).
Unfortunately, if the double charger is turned on (whether charging anything or not), or if the single c charger is charging, I lose all DAB signal (aftermarket JVC single din unit with windscreen mounted internal DAB aerial). All this kit is from MUD so should be pretty good quality. I’m reading this is a common problem, but also all sorts about EMI, ferrite clip ons, foil wrapping etc. What can I do to fix it?! Thanks. |
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5th Nov 2022 7:13pm |
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| PCM Member Since: 25 Jan 2019 Location: North East Posts: 862
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The jvc mudstuff half depth unit has a known (by manufacturer) issue with DAB reception. The receiver is really poor as they’ve squashed so much into half the space.
It was so bad up my neck of the woods that I ended sending it back and getting a full depth one with a different receiver chip. Try ferrite rings but you’re going to struggle. Sorry if this is not the news you wanted. |
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7th Nov 2022 1:47am |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 19651
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That is indeed often the case a lot of DAB equipment isn’t that great.
The Nakatanenga DAB aerial has a lot of good reviews, that’s why I went for it but the HU equipment is a factor as well. Glass mount DAB aerials are often not great. Best thing to do is go by reviews of others that have good ones. Ferrite clips and aluminium foil shielding definitely did make a tangible difference on mine - it is not a fruitless task despite at first glance it may sound not worth the effort. The issue with it is it is quite a task to get at it all, and the aerial cable is a real pain. It’s an ideal job to do if you ever have the dash out, even a bit of foil on the external DAB unit should help but it did everything on mine as I had a good opportunity to do it. In effect you want to shield everything except the antenna itself, and ferrite clips on power supplies. Zip ties, and fire rated clutch electrical tape are useful as well as aluminium adhesive tape and Mylar foil. Emergency foil blankets are ideal as a Mylar foil item, you can just cut it up. Whatever system you have though there will always be blackout areas, all you can do is improve the signal as best that you can. Diesel$ Live$ Matter. ⛽️🛢️👨🔧🧰⚙️ RED, WHITE & BOOST! 🇬🇧 |
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7th Nov 2022 11:03pm |
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| ScarboroughSeadog Member Since: 21 Jul 2022 Location: Scarborough Posts: 110
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So- ferrite clips on the power supply (positive only?) to the USB chargers (how many clips needed?), and Mylar foil wrapped around the aerial wire for as much of it as possible?
My other LR is a 40 year old FFR Lightweight- where all the major cables are sleeved in mesh to suppress interference to the radios- some similarities! |
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7th Nov 2022 11:29pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 19651
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One clip nearest device but near supply is idea too. They come in various sizes, some times it may pay to put one on each feed ground and live, or if a bigger clip you can put both live and ground through the same one.
The have packs on amazon, I needed two packs for mine but I did have a lot to do. The usually come in various size clips, the most snug fit is ideal, if large and you have no choose you can loop the cable around twice. And yeah, the goal is to keep a clean signal and prevent EMI. USB chargers and LED’s and associated electronics are often culprit for producing high EMI. In particular cheaper LED light bars and LED lights, but even a Relay does produce EMI from its copper coil. Only thing to be careful of is anything that needs ventilation, be careful not to cover and ventilation holes or fans etc. If heat is likely to be an issue, then aluminium tape maybe better as it’ll be easier to dissipate heat from. At a guess I’d say it gave a 50% improvement of signal lock and quality, and I do know it declined a little after I fitted various electronic devices hence doing the job. As I have HDMI switches and things like that in the dash. It also works for digital TV signal too, as I have three antennas on mine amongst other things. I made Mylar shielding sleeve from Mylar foil, double sided tape and 50mm wide Alu foil finished off with cloth electrical tape to neaten up. You can buy shedding sleeve off the shelf, and wrap but it isn’t not cheap…… And does the same job. I did mine foe around £20, off the shelf would have been a good £100 and even then wouldn’t have done the electronic devices. If anyone has a Naka DAB aerial they want to fit, I’d definitely recommend shielding the entire cable and associated little unit when fitting it. The trouble is if you just stick Alu tape to the cable is that it’ll make the cable more stiff, not and mailable (bendy) and might crack the cable sheath and very likely will crack or break the aluminium tape defeating the point in shielding it oh and silver of course. Dynamat tape would even work but is more expensive and only a waste of money compared to standard aluminium tape. Making a sleeve, means it’ll come off clean with no tape residue if you wanted, it’ll slide on the cable and it slows the cable to freely bend where ever you want it to. On joints you just have to overlap. Or buy off the shelf shielding wrap at cost, and use Mylar for other items. Beware what you stick aluminium tape to, as obviously once it is on it’s not so easy to take off so if you put it on plastic threads as an example it maybe a problem to get off. And best kept away from stainless. I was undecided if I’d bother but, I thought I’d give it a go as I had it all out this summer and it worked. I was very pleased that it want for nothing, I had my doubts but it was worthwhile.  Diesel$ Live$ Matter. ⛽️🛢️👨🔧🧰⚙️ RED, WHITE & BOOST! 🇬🇧 |
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7th Nov 2022 11:58pm |
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| MadTom Member Since: 10 Sep 2013 Location: Olomouc Posts: 581  
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If you have bare cable without mounted connectors, easy and cheap way to get some shield is to remove the outer conductor mesh from coaxial cable (like RG58 od RG213). For just a few meters is is much cheaper than buying EMC cable shield.
But first try to switch off possble interference sources (like the USB charger), to identify, where the interference is goin from. Best way is to suppress unwanted emissions on the side of their source, than trying to block them on side of receiver or more receivers. "Drobek" = The Small One - Discovery 2, "Blufínek" = The Blue Thing - Defender 130, and for me at least Ford Mondeo  |
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8th Nov 2022 11:56am |
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