 | Home > In Car Electronics > Radio reception issue |
 
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20375  
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Is it Amplified?
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1st Nov 2014 3:36pm |
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| gilarion Member Since: 05 Dec 2013 Location: Wales Posts: 5110  
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Yes it is an amplified aerial and a very good one.
Wher are you drawing the 12v from to feed the aerial, usually you use the power line output from the radio that would normally power an electric ariel. |
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1st Nov 2014 3:46pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309 
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I am using the cigarette lighter as I didn't want to interfere with the radio harness.
I think it could be interference from the 2 USB sockets I have Looking online for a choke mode filter Hoping the sparkys on here can advise - thinking of getting this one http://cpc.farnell.com/wurth-elektronik/74...dp/FT01358 |
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1st Nov 2014 3:57pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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I checked the antenna with a meter and it is getting 12.6v on the power line and a good earth as well
Interestingly enough the USB ports are also connected tot he cigarette lighter (own separate fuse) I am going to test this theory by disconnecting the USB ports and checking radio reception However I need to wait for an hour as I entered the radio code incorrectly three times (I thought the presets were for the numbers and on checking the manual you have to just use presets 1,2,3,4 and press each one the amount of times to make up the number in the code |
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1st Nov 2014 3:58pm |
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| gilarion Member Since: 05 Dec 2013 Location: Wales Posts: 5110
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Could well be the usb sockets if they are on the same power feed.
The trouble with high gain amplified aerial is they are very sensitive and will pick up white noise or interference from any electrical item that is not suppressed or filtered. Just out of interest have you tried the reception with the 12V feed disconnected to the aerial to see if that makes a difference. if it does then change the feed. You have not said where you have fitted the aerial as sometimes just re locating it can make a hell of a difference. |
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1st Nov 2014 4:49pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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The aerial is on the wing where the original was.
With the power to aerial disconnected there doesn't seem to be a huge difference. Actually the stations are being picked up well but there is crackling background noise I haven't disconnected one USB feed as it is a bit more awkward to do so cannot check if it is the problem - I may just filter it and see if that improves the situation |
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1st Nov 2014 5:19pm |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731  
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I have a similar problem - I have two TomTom iPhone cradles (SatNav + Spotify) running off USB sockets powered from the lighter feed wiring behind the dash. One cradle is plugged into Aux (standard LR CD/Radio).
When they are plugged in you can forget about radio reception unless you are sitting on the transmitter... At first I tried every option, including changing the wing aerial and radio (!) until I finally figured out it was the cradles. We live in a poor reception area anyway so it didn't occur to me that they were at fault as I hadn't tried listening to the radio for two weeks after fitting them 
In the end I fitted a switch near the radio to kill the USB sockets in the unlikely event I want to listen to German radio  Tell someone you love them today because life is short.
But shout it at them in German because life is also terrifying and confusing... |
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1st Nov 2014 5:57pm |
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| Tiger Member Since: 06 Jul 2012 Location: Wales Posts: 2265 
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Interference sits on the common Earth.
Electricery is lazy and always uses the past of least resistance. Find a bloody brilliant earthing point and Earth your radio and aerial to it using a decent wire. |
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1st Nov 2014 6:05pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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Yeah this has been driving me crazy as this is the second aerial I tried.
I was about to buy a new head unit when I thought - let me try the one from my other car which works fine - and it had the same issues i saw this thread which made me realise it was probably my USB installations http://www.defender2.net/forum/topic26844....+reception I am going to try this and see if it helps - but not having spare bits lying around, it will be cheaper for me to a buy a filter |
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1st Nov 2014 6:05pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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I believe both are well earthed having tested resistance of earth to chassis Have not tested resistance of earth all the way back to battery |
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1st Nov 2014 6:06pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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I have established that it is indeed the USB items causing radio interference - they are all on the cigarette lighter circuit so I removed the relevant fuse and voila - perfect reception even though the aerial becomes passive with the cigarette circuit disconnected.
Will be experimenting with some common mode chokes as soon as some capacitors get delivered next week Shax on here has kindly sent me a ferrite ring with cable wound round in right phase so hopefully will be able to have all USB devices and radio in full working order |
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8th Nov 2014 2:02pm |
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| gilarion Member Since: 05 Dec 2013 Location: Wales Posts: 5110
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Would it not be easier to find an alternative live feed to wire the USB sockets to.
Just a thought but what do you charge with the USB sockets and what power do they draw. Without a voltage regulator attached in line 12V USB supplies can cause spikes that can damage some phones and other sensitive devices notably Sat Navs. I would suggest that you determine what voltage your devices use and install a fast blow fuse of that voltage into the live feed. |
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8th Nov 2014 2:15pm |
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| kmac Member Since: 07 Oct 2009 Location: Middlesex Posts: 1309
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I have a dashcam which takes 1A at 5V) and a Satnav which is the same. Each has a fuse protecting the equipment
I don't think moving them to another live source will resolve the problem In fact i believe it is one cheap component that I got on the internet that is the cause -converts 12v to 5v needed by dashcam and satnav ( they each have one) http://www.ebay.co.uk/itm/DC-DC-15W-Conver...7675.l2557 |
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8th Nov 2014 3:38pm |
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| landy andy Member Since: 15 Feb 2009 Location: Ware, Herts Posts: 5707 
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My blue sea USB port causes my radio interference, and the worst thing plugged into it is an original Apple cable.
Andy |
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8th Nov 2014 3:54pm |
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