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Thats ok if you have a PVC.....not many coachbuilts with tin roofs.I just used a cheapy magnetic one from Halfords and put it on the roof
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does anyone have experience of fitting an aerial for DAB
Their trade prices are pretty competitive.Halfrauds and cheap should never be used in the same sentence.
Halfrauds ARE NOT CHEAP.
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still haven't got the radio to work on DAB ,
can you show a picture ?I use a small magnetic mount aerial from halfords. I glued a large washer to the plastic trim in the quarterlight window frame of our A class... works a treat...
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Here you go Jim..can you show a picture ?
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Here you go Jim..
The window frame slopes, so I bent the twig at the base so it stayed vertical...
The camera angle makes the aerial look all out of kilter, when it actually isn't...
It is a DAB aerial. Got it at the same time as the new stereo from HalfordsI'm surprised you can get DAB on that aerial, thought it was really fussy about reception ?
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I'm surprised you can get DAB on that aerial, thought it was really fussy about reception ?
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just recently bought a Sony DAB radio and Autoleads window film aerial.. from Halfords..
still haven't got the radio to work on DAB , I think it's because the Hymer has no metal in the window A pillar to ground the aerial.. think I'll need to run an earth wire up to the aerial to give it a ground plane
The aerial instructions make no mention of heated windscreen, but advise against mounting on polarised screens. .
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Wellllllllllllllllllll.
I have tried to find out what the impedance is of a DAB car radio is but no luck so far.. So this is an approximate design and does not take in to account velocity.. And Skin effect will depend on materials used for the construction.
It is based on an expected impedance of 50 Ohms.
This is what you are looking to end up with:
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It is the simplest design I can think of .. Originally meant for circular polarisation but it will work well on vertical and horizontal transmitted signals..
In fact the whole thing would have to be a compromise as said previously as the band width involved is massive to say the least, so the dimensions I will suggest are for mod band..
It could be made using some brake pipe or similar..
basics
Take a bit of something or other that has an over all length 68 cm
make a bend at 17 cm as in the above picture
Get some thing that has a circumference of 34 cm and bend the pipe around that ( again, as in the above picture )
bend the last 17 upwards..
As I say, all of this is a compromise and the antenna is not going to be used to transmit through so none of this is particularly critical
Coax.
Ideally use a length of coax this is multiples of 1.5 metres / .95 .. ( so for instance if you want about a 3 mtr lead it should be 2.85 mtrs long )
Again, I am presuming the impedance to be 50 Ohms.. if ( IF ) that is the case then something like RG58 will be perfect and is very cheap from any shop dealing with electronic type stuff.. Maplins stock it or its equivalent
Mounting.
If you use the correct ( again approx. ) length of coax you will have effectively made something that is called a ballun ( a posh word for a transformer that works at RF frequencies ) and in theory you should only need to connect the centre core to the centre of the horizontal ring
You can literally through the thing on the roof or somewhere suitable and it should work ( though putting it in to a plastic box and gluing it to the roof with a bit of sikaflex would be fantastic )
A much better option would be to make two of them and place them back to back..Join the centre core to one and the shielding to the other..
Now THAT is proly as close as most folk will want to go to the full on 'correct' answer to the issue
However.....................................
After a bit of research I have discovered that more and more transmitters are swapping to circular polarisation and boosting their output power to compensate
With that in mind here is a REALLY simple design and solution
A straight forward vertical antenna, just like a standard car aerial
BUT.. Not quite standard
Replace the coax ( car aerials have a very strange type of coax that is used to 'kid' the radio in to thinking the aerial is MUCH bigger than it really is ! ) with some RG58 and fit the correct plug to it for your radio ( coax length is not critical )
Cut the antenna to a length of 36cm ( presuming a centre frequency of 200 meg )
What you have done is make the standard antenna in to a 1/4 wave end fed ground plane type
Job done
Bet some of you wish I had never said anything now LOL !!!!!!!
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That's what I didWell, finally solved the problem !! And in a very simple manner too.
I bought a £15 magnetic mount DAB aerial from Halfords. Then got a little piece if 3mm steel plate, a little bending and painting then attached it to the top of the awning box. Works a treat !!! Not obscured by anything. Picks up everything all over the Country apart from it dropped out for a few minuets in the depths of Norfolk.
The cable length on the aerial as supplied is 5m and I had to buy a 2m extention to reach the radio. I took the cable in via a cover to the grill (which has been removed) as I am totally adverse to drilling holes in the bodywork when it's still under warrenty.
The photos below should explain all. Just wish there was a need for a few more aerials to go along that rail.
View attachment 86827 View attachment 86828
I just used a cheapy magnetic one from Halfords and put it on the roof
We have a windscreen mounted "stick on" DAB antenna and it's not actually that bad. It's not 100% but it's many many times better than the FM reception we get. I don't suppose it makes much difference but it's a Pioneer head unit and a Pioneer antenna. I believe that the radio whenever it can, holds the DAB and FM signals for the station at the same time and automatically switches between them to maintain the coverage as much as possible which seems quite a clever trick.
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