Van-Aerial disease or DAB in a Defender.

[GBMUD]

Hi, perhaps someone can help?

For a number of reasons I have today fitted a Kenwood DAB radio in my Defender. My RangeRover has an OE DAB and that works splendidly almost everywhere. 

In the Defender though I cannot get a decent signal. I did manage to get some local stations with a very weak signal but nothing else - no BBC or other national stations. I have a stick-on windscreen aerial bought with the stereo at Halfrauds. 

The aerial has an earthing strip that has to be attached to a painted metal surface. I had to cut a slit in the windscreen rubber to allow it to pass through and stick to the frame - but is a Defender window frame adequate for the job?  There is also a built in booster in the aerial which is powered by the head unit - this function is enabled on the head unit and it does not report an aerial fault.

So, anyone got an aftermarket DAB in a Landrover and found an aerial that works?

Photo attached I think  

Cheers

Chris

[GW8IZR]

I just split mine from the roof mounted FM antenna and its fine.

The splitter was from Amazon and cost about 20 quid - it has an amplifier which needs power from the radio.

It wasn't this one but basically the same unit

https://www.amazon.co.uk/d/Car-Vehicle-Electronics/DAB-Aerial-Splitter-Amplifier-Adaptor-Radio-Active/B00U3T527O

 

[SPendrey]

I've been running a cheap 'Mutant' unit (so cheap it says "tunning" when switching stations!).  Anyway... I use a magnetic external aerial, which I guess wouldn't suit a Defender?  This means I can pop it off the roof while in wooded areas.

[Cynic-al]

I've found with DAB the best aerials are the roof mounted shark fin which requires drilling, headlining down etc to fit, however I have found a close second best are the ones like the old mobile phone aerials where you stick a bit on the inside and a bit on the outside of the glass with a little aerial. The third are the ones that stick all inside the glass and have a plastic bar about 10" wide? All were powered from the radio end and I've never had to earth any of them at the window.  I'm not really sure what it's going to achieve attached to a painted metal surface? Surely it should be a bare surface? Maybe try just clipping a lead to it and attach it to something more substantial as a test see if it improves things?

[Arjan]

DAB (Dead and Burried) seems the way forward..

How is reception in the UK while on the move, compared to FM ?

I need to consider getting one as on the Continent it also is being pushed very hard....

[reb78]

A pigeon destroyed the FM aerial on my 110 whilst on the M6 some time ago. I thought about going to DAB at this point, but havent bothered as i have such a large data bundle on my mobile that I just stream the radio from the web and play through my stereo via the aux cable. I seem to have reception that is good enough to cover most areas without any issues. Personally, I think the way the mobile contracts are going (more and more data, with better coverage and many now allowing use abroad), this will be a neater solution in the long run than DAB and negates the need to buy anything DAB based.

[GW8IZR]

3 hours ago, Cynic-al said:

I've found with DAB the best aerials are the roof mounted shark fin which requires drilling,

Just to be balanced on this NO shark fin antenna will work as well as a roof mounted 1/4 wave antenna at minimal SNR.

They may well be convenient, practical and effective but at extremes of coverage which sadly means most of the UK they are not as good.

[GBMUD]

Thanks guys.  I will have a fiddle tomorrow and see what I get...  I will try a good earth connection at the aerial end first, followed by SimonR's suggestion of a 34cm length of TIG wire on the end of a bit of coax...  If that works then I will look for a decent through body antenna.

Arjan, DAB in my Rangerover work perfectly, minimal drop-outs in southern England, totally clear all the time, loads more stations and probably better then FM for coverage.

Reb78, I have used mobile data for radio before but would prefer not to rely on it - locally I do not have reliable enough signal.  The reason for buying DAB was to get Bluetooth for podcast and audiobook listening - and I decided that if I was getting a new head unit I was going to have DAB on it too!

Chris

[SPendrey]

18 minutes ago, GBMUD said:

<SNIP>

The reason for buying DAB was to get Bluetooth for podcast and audiobook listening - and I decided that if I was getting a new head unit I was going to have DAB on it too!

Chris

There is only one reason for getting DAB... Planet Rock!

 

On the reception side of things, I too get a great signal almost everywhere I go.  Patchy in mid-Wales, and also on Salisbury Plain.  Elsewhere though, it's excellent.

[pat_pending]

The windscreen aerials are rubbish, when I first fitted mine it was fine until I got down the road and the signal kept dropping out. I think it's due to the Defender screen being near vertical.

Don't waste time trying, it'll never get any better.

i replaced it with a stubby mag' mount one, stuck to the roof rack, £15 delivered from ebay, comes with 3mtrs of coax.

Used the same type on the car and reception is perfect.

And yes, Planet rock cranked up loud, drowns out a tdi

 

 

 

[martyn668]

The

The wife had DAB in her car - rubbish with a stick on aerial, better with an additional 6" long magnetic mount jobby, but the signal was still patchy. Then the radio packed in and we've gone back to FM, just for convenience, but separate DAB radios (to feed an AUX input) seem to have got more complicated and more expensive. We've got a DAB in the house and it's fine for Radio 2 (not my choice) and rubbish for Planet Rock. It used to be OK, so I guess they might have reduced the signal strength on PLanet Rock. Surely being digital they share the same transmitter, or are they being as stupid with this as with analgue radion transmitters and mobile phone cell coverage? I know they're reducing signal strength on FM transmitters, so I can clearly get BBC Cambridge everywhere locally, but not R4. WTF?

I've given up on radio - just listen to MP3 unless I'm in an area I can get R4, which fortunately is about 90% of my commute (in a Honda with factory fit radio, so not a LR radio problem).

Everything was simpler with crystal radio sets and long wave. Harrumph.

 

Edited June 14, 2017 by martyn668

[Cynic-al]

Yes I can see that a long aerial would be better than a shark fin, the one I had was better than the internal window aerial. I swapped that to the type where you stick an aerial on the outside of the glass and the cable the opposite side of the glass which was an improvement.

Mine drops out from time to time but is a lot better than it was years ago. They seem to have improved local and national ensembles. The only place I've really suffered recently was when I went up to Northumberland, basically nothing. I've streamed radio at home but find it frustrating if you want to flick channels, slow to load and I often have no phone signal at the places I go never mind mobile data. I find DAB is easier to use than phone apps but still isn't as easy to use as FM. On FM you can just keep pressing the retune button as you drive around the country but with DAB you have to either stick with a national ensemble or keep rescanning which I find distracting whilst driving. If you mostly stay in the same area it's less of a problem. 

 

Streaming MP3s is great if you have a music collection, I found mine got to such a size that I couldn't be bothered to organise it and stopped downloading and got bored of the same music going around and around or playing songs that I didn't like any more. It became a job in itself managing it so now I just flick through radio stations until I find something a like.

Edited June 15, 2017 by Cynic-al

[=jon=]

DAB coverage is OK round the south west - there's places where it'll drop out (inc. one section of the M4) if you aren't on the BBC mux though.

One thing that's really annoying is that the bitrate for non-BBC channels is only 96kbit, compared to 128kbit for the BBC channels, which gives a noticeable drop in sound quality, even compared to FM

[GW8IZR]

Yes its hard to define 'better' but in all cases an external antenna of almost any type will be better from a pure radio perspective. Of course more susceptible to physical damage and more likely to draw attention to the fact that the vehicle contains a saleable radio making it worse.

Some sharkfin antennas use a dielectric block to electrically lengthen the physically short antenna element  and tend to work well, they tend to be OEM stuff and not typical ebay fodder. 

Some sharkfin antennas are nothing more than an electrically short probe and an amplifier, they are no better than the very short magnetic antennas.

The short magnetic antennas are not bad if mounted on the roof, in the clear ( away from roof racks etc.. )  and can be stuck to a defender roof with sealer or double sided tape they will work well enough.

A whip antenna cut for DAB will still work well enough on normal FM and will be the 'best' RF performer, They should be mounted to the skin of the vehicle and they are very much better at ignoring the effects of vehicle noise. I always use Panorama antennas - the M8 modular base is practical and there are millions in service throughout the world. I have two GPS mounts on mine, a VHF comms antenna and the same but cut for  DAB. With flexible whips they dont break but I no longer bounce my 90 of trees... or take it out in the rain.....

The stick on windscreen antennas are not poor performers due to being vertical etc but they are poor because the length of the antenna element is closely coupled to the screen frame or bodywork. They are also screened from many directions by bodywork. This makes them poor in absolute terms and In TD5 equipped vehicles they are also more likely to be degraded by virtue of their proximity to the vehicle ECU. There is a significant amount of VHF noise generated by the TD5 ECU which can make any VHF installation a challenge.

That is the single reason that my 90 rebuild has an earlier RF noise free engine, pity its not acoustically silent as I might be able to hear the DAB bitrate limitations ;-)
 

HTH

[GW8IZR]

2 hours ago, Cynic-al said:

 the one I had was better than the internal window aerial. I swapped that to the type where you stick an aerial on the outside of the glass and the cable the opposite side of the glass which was an improvement.

 

Yes I think Procom sold a great many of those in the 90's when 200MHz trunked radio systems were nearly popular enough to make a living out of them. Thats the same spectrum that was sold off to make the DAB allocation. I probably have one of those antennas in the shed somewhere ;-)

 

You have done exactly the right thing, get the probe outside and clear of the tinwork.

 

[Peaklander]

Don't 1/4 wave verticals need the metallic surface of the mount area to act as a virtual image and so the antenna acts as if it's a proper 1/2 wave with the correct match at the cable join? This implies a good ground connection to plenty of metal is needed!

[GW8IZR]

Its more related to impedance matching but yes a connection to a 'ground plane' is required. It does NOT need to be a DC connection, the connection is an RF connection which can be a capacitive connection. That's why a magnetic antenna will work just as well with an insulated cover on the magnet or as suggested .. with double sided tape or glue.

 

(edit) lots of urban mith and folklore round this, often you will read things like connecting an earth wire direct to the chassis etc.. which are always masking another issue not a requirement for the function of the antenna..

[nickwilliams]

I've fitted one of these http://www.dabonwheels.co.uk/Kinetic_DRA-6001_FM-AM_DAB_car_aerial.html which seems to work very well. it's mounted towards the rear of the roof. It's feeding a Blaupunkt radio/amplifier (http://www.blaupunkt.com/en/nc/products/car-multimedia/car-radio/products/single/7589/). The installation works at least as well as the factory fit system in my Peugeot estate. 

Edited June 16, 2017 by nickwilliams
Typo

[GBMUD]

I thought I should provide an update to this topic.

Thanks everyone for the responses and ideas.

I returned to Halfrauds to ask their advice on whether I had installed the window aerial properly.  The response was that I should have bared the paint back from the windscreen surround before sticking the earth foil.  Also, fitting the earth foil absolutely smooth with no creases or bubbles is important.  They gave me a new aerial FOC which I fitted as they suggested and lo, it was no better.  Then I had a thought.  I disconnected the two USB chargers that were on in the car and immediately Radio 4 started playing clearly.  The RF output from the cheap USB chargers was upsetting it.

After a couple of days DABing I was finding that there were still a great many drop outs and it was not really satisfactory.  After several visits to Halfrauds and failed attempts to 'Click and collect' I was able to buy a magnetic DAB aerial from them - £14.99.  I know what you are thinking, but I already have a galvanised steel plate stuck to my roof from a past project, so I was able to install the magnetic aerial on the back of my roof.  Instant improvement, I no longer get regular dropouts of signal, though I have not used the Defender a lot since so there is more testing to be done.  The magnetic aerial will be vulnerable off-road, but hopefully it will just hang off the back of the car when going under low trees etc. and will not get damaged.  Time will tell.

Once again, thanks for the suggestions.

Chris

[SPendrey]

I found this weekend that my Bearmach boost pack (much like one of these, but not in a blue box) ruins DAB reception when plugged into the cigarette lighter to charge.  I also learned that it loses 25% charge (judging by the 4 LEDs on it) over a period of about 3 months.

[SteveG]

Sorry Chris, I've only just seen this thread. When looking at an aerial for the RRC, this is supposed to be best for DAB reception...

http://www.dabonwheels.co.uk/Kinetic_DRA-6003_FM-AM_DAB_car_aerial.html

pricey, but constantly comes up as offering best performance. 

Cheers, Steve 

[V8 Freak]

52 minutes ago, SteveG said:

Sorry Chris, I've only just seen this thread. When looking at an aerial for the RRC, this is supposed to be best for DAB reception...

http://www.dabonwheels.co.uk/Kinetic_DRA-6003_FM-AM_DAB_car_aerial.html

pricey, but constantly comes up as offering best performance. 

Cheers, Steve 

and if strategically placed to avoid damage coupled with the the mast being removable for off-roading / bushes and obstacles.... nice find Steve...

[GBMUD]

On 7/11/2017 at 9:15 AM, SteveG said:

Sorry Chris, I've only just seen this thread. When looking at an aerial for the RRC, this is supposed to be best for DAB reception...

http://www.dabonwheels.co.uk/Kinetic_DRA-6003_FM-AM_DAB_car_aerial.html

pricey, but constantly comes up as offering best performance. 

 

Thanks Steve.  I saw that one but found the price to be unpalatable.  I am pleased to have found a solution which I am happy with for now.  If it turns out to be a dud long term I will reconsider.

Chris