IM DOING THIS POST FOR ANOTHER FORUM, UNFORTUNATELY THEY CANT SEE THE PHOTO LINKS SO ILL JUST GIVE THEM A LINK DIRECTLY TO THIS POST SO THEY CAN SEE THE PHOTOS. MIGHT ALSO COME IN HANDY FOR YOU GUYS.........
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Done lots of searching on the internet for DAB antenna designs for cars and whats being sold in stores and on line. Im a licenced radio amateur and done lots of studying and field work on how antennas work, dont get me wrong Im no expert but alot better than these store fraud assistants.
Anyway lots of people advising on what to buy and why, a bit like amateur radio lots of amazing claims of high gains from these antennas, I would say 99.9% of them lies, no video or photo evidence so I thought I would do just that to help those looking to purchase these antennas.
The story so far and from the beginning.
I bought a pioneer DEH-6500DAB radio from Halfords, next I needed an antenna now this is where I didnt use my instincts or my brains, Im a licenced radio amateur and studied antenna design for many years, the guy in Halfords told me they have had no problems with the Autoleads DAB Film Antenna SMB - DAB-AA1 a windscreen type antenna@ £19.99 and that its the only antenna they fit although they do sell others.
I told the guy that surely a body mounted antenna or magnetic antenna at the correct length would be a better option, his reply was because of the signal strengths that he would still go with the windscreen antenna as its more pleasing on the eye and that I wont experience any problems at all, my mistake was I listened to him.
Anyway got back home and fitted the stereo and the antenna hiding all the cables, fitting the 12 volt supply to the antenna and fired it up and yes we have DAB maybe the guy was right after all, driving around I soon found that he was wrong, the signal kept dropping out I was furious after all the work pulling the pillar panel off and getting everything neat and tidy.
I went back and told the guy how I felt about it all and asked for a replacement, a magnetic antenna, Sonichi Magnetic Roof Mount DAB Antenna @ £14.99 as this had to be better and is what I wanted in the first place although still sceptical looking at the coax and how light and bendy this antenna could be in the wind.
I drove home thinking why didnt I just get my money back and make my own.
Anyway once home I got the camera and started taking some photos as I tested this magnetic antenna against the stick on screen power assisted rubbish.
Here was my findings...........
The first test was with the autoleads dab film antenna smb-dab-aa1 stuck on the windscreen, the first one I purchased .....
You can see in this photo the lead is plugged in
And here is the signal
Now for the second test using the Sonichi Magnetic Roof Mount DAB Antenna, you can see its plugged in, the tape is only there to show its the other antenna, I hadnt even wired it through the car it was just to test first as I had already made that mistake once lol
You can see here I wanted the antenna to be mounted in such a way that it wouldnt have an advantage over the on screen antenna, Ive stuck it on the wing low down, lower than the on screen antenna, and my car was parked on the drive facing the wall of our house, trying to block the signal here as much as possible.
Here is a view from inside the car, this shows Im not giving it much of a chance to work.
But here is the signal, a full signal.
I didnt want the cable going through the door so thought I would feed it through the boot and into the car, I also wanted the antenna on the roof, any radio amateur will tell you if you want an omni directional antenna, that means an even signal no matter which way you are facing then stick the antenna in the centre of the roof as high up as you can, if you stick the antenna at one end of the roof or one end of the car then it will become a directional antenna.
The centre of the roof is always the best but unfortunately the cable was not long enough so I thought I would give it a go on the boot lid, now again the centre is better but I wanted my antenna to work harder lol, so I stuck it on the end as close to the back window as possible, again I had full signal and the antenna looked more tidy.
So whats the best sort of antenna you can get ..............
Well I think a body mounted antenna cut at the correct length using good coax of 50ohms but this means drilling your car, you also need as good an earth as possible so after drilling sand down the paint on the inside of your car not the outside lol so lets say its on your boot lid, drill through sand the inside.
Or go for a magnetic mounted antenna, the larger the magnet the better chance of a good earth although this tiny magnetic antenna is working fine for me.
DO NOT USE THE WINDSCREEN TYPE ANTENNA, THE LAW OF PHYSICS SAYS IT WONT WORK VERY WELL. YES I SUPPOSE IF THE SIGNAL STRENGTH IS AMAZINGLY STRONG IN YOUR AREA THEN IT WILL WORK BUT SO WOULD A PIECE OF WIRE TBH.
I am going to make my own antenna, a good strong antenna that wont bend in the wind so even less chance of drop outs, it will have a larger magmount so will withstand high speed driving without the worry of it blowing off and will be checked on my antenna analyzer to see what sort of SWR reading I get, it wont have any curly base or anything like that to make it look fancy, it will be a straight whip measured and cut to the correct length.
Come back and check out my next tests to see if I get any drop outs at speed, and to see if the antenna stays on lol.