How to add perfect DAB reception to original aerial, easy and reversible

[neuerberli]

I've been toying around with the idea of installing the perfect dab and FM aerial ever sind I bought my Berli in 2009. Exchanging the stick, either FM was ok and DAB lousy or vice versa. Finally I found the solution that works. FM reception with the "long" aerial remains unchanged but DAB will be as good as possible. "Station count" is up from 45 stations to 74 now. everything is quite easy to do an it's reversible.

You need:

- sticky (Scotch) tape
- shrink tube (I bought a refill for "Set 2000" at "Conrad")
- about 50cm of wire, preferably the core of a coaxial cable for TV
- scissors
- soldering iron or something else to "shrink the tube"

Since the FM aerial doesnt work for DAB and vice versa, what will work is when you simply "glue" the two aerials together at the base. You will need a wire 41.5 cm in length measured parallel to the original stick down to the thread at the base. Remove the last few cm of insulation and wrap the wire 2-3 times around the thread.
It's important, that there is a connection at the base and that the overall lenght is 41.5 cm.

Now "glue" the wire to the original aerial in a few places with stick tape. Then use shrink tube over the whole 42cm, so everything is well attached.
Now you'll have a 2in1 - FM and DAB antenna with great reception and without compromising. It really is this easy..

   

Original "long" aerial, presented by my czech work buddy

   

both aerials parallel

   

base

   

final result

   

shrink tube

[3rensho]

Ausgezeichnet!! Vielen Dank neuerberli.

[BigC]

Sounds Interesting lol....might try this...
Thank you
Regards
C

[Henk50]

Great idea! I will also have to switch to DAB. How did you calculate the length of 41.5mm? On most places they are talking about 31.5 - 35mm
I suppose you have a combined DAB/FM connector on your radio? JVC has 2 connectors, in that case I think I should not connect to the areal-thread, but make a small hole and connect it to a separate coax-cable?

[neuerberli]

Great idea! I will also have to switch to DAB. How did you calculate the length of 41.5mm? On most places they are talking about 31.5 - 35mm
I suppose you have a combined DAB/FM connector on your radio? JVC has 2 connectors, in that case I think I should not connect to the areal-thread, but make a small hole and connect it to a separate coax-cable?

Thank to all of you. I really didn't expect it to work, but it does. I believe you can wire as many antennas together as you like if only they are tuned to different frequencies. I added an aerial 10.4 cm long for DVB and one 4cm long for UMTS/whatever. Didn't test those two by now, but DAB and FM reception is still unchanged, despite this further modifiction.

I didn't calculate the length, I unsed trial and error. My aim was to receive one or both of the very weak transmiters in dontown Augsburg (channel 9C, 10 KW, distance about 60km) an in Pfaffenhofen (channel 11a, 10KW, located close to Ingolstadt, about 60km too)

Both were non existant in my channel lineup before, only the 46 stations transmitted from Munich were recievable. I wanted to optimise the aerial to those channels and expected the lenght to be around 36cm (1/4 of the wavelength)but 36 cm resulted in very poor reception. The optimum for both transmitters together was round 41.3 to 41.5 cm, while the local stations reception remaind unchanged at 100% .

I have a Sony 2-DIN radio for FM and a Pure Highway DAB+ reciever. I soldered an aerial input to the Pure Highway and glued it to the left of the radio with superglue    Sticks perfectly. I have made some photos in my other thread. I used a very common 2 way splitter for cable TV/radio 5-900 Mhz with f-Sockets for about 3€ hidden in the dashboard. I also had the option to mount a frequency selective (FM-DAB) splitter, but the result wasn't as good.

You should be able to use the original cable. It will work fine at DAB an FM, all you need is the spitter and the correct adapter cables for the radios. Get a soldering iron and DIY, doesn't cost a lot. Don't make extra holes but use the aerial-thread. For perfect results, mount a VHF amplifier as close to the aerial as possible inside the car.  Can be any amplifier up to 30db for cable TV/radio (FM and Band III) , that is small enough, has decent sockets and works on 12 Volts.
DAB is broadcast on former TV band III.

[neuerberli]

https://adko.eu/Antenne-Verstaerker-mit-...il-AWS-03F

This is the amplifier I use in my Berlingo. Works on 12 Volts, 2 outputs, one combined input for FM and DAB and one for DVB.
DVB will be used later, so far I just don't connect the input. Amplification around 28 DB, 40-230 Mhz (FM, DAB but no AM...)

cost 19€. I'm still looking for something "even better" from China, preferably 1-2000 Mhz with low, low, low noise.
Just added a BNC-outlet on the plastic covering the "A pillar" in front of the passengers seat and connected it to the aerial.
Now all the goodies of "software defind radio" are accessible in my car on my smartphone. Just need a driver..

[Henk50]

This weekend I followed the DIY tutorial.  First I added the 41.5mm wire (1,5mm2) to the existing aerial:

[Image: IMG_7921_zpsiwubvtbk.jpg]

I split the connector to a AM/FM plug and SMB-F DAB+ connector. The result was poor, too weak signal for DAB+.
Somewhere I found a 18db TV-amplifier with 2 outputs.  After some soldering, I connected the AM/FM and DAB to the two outputs. The result is acceptable, but not perfect.
Because the amplifier is for high frequencies, you're unable to receive AM-signals now!
For the time, it's OK.
Thanks Neuerberli!

EDIT: I have changed my conclusion! After some testing today, this aerial is better than my (expensive) Calearo 16V COMBI 7677932 in my other car with nearly the  same radio (JVC KD-DB97BT). The sometimes weak signal is related to the fact that my area is not optimal covered for some transmitter-stations.

[neuerberli]

   
Looking good. :-)

3 days ago my 6,99€ broadband amplifier from china arrived. Bought from ebay it claims to include AM down to one MHZ and everything up to 2000 mhz. Tried it last night. 1 MHZ is about right. Many AM stations between 1-1.6 MHZ were receivable but not much below 1 MHZ
DAB and FM is good and unchanged. Wil be trying some more SDR soon, maybe hook up my old shortwave receiver too.

Tested DVB today... DVB-T in Munich was switched off in mid April and replaced by DVB-T2 so  I expected no DVB-T receptions at all, yet I receive 12 channels threefold from 3 different locations 1) Hohenpeissenberg, 2) Ausgburg and Pfaffenhofen and 3) Grünten. I'm amazed! 

This amp IS recommended.