Andy7 wrote:
Magmounts !!! ??? Do you recommend these?
Here's a question Radioman. Why do we have to get rid of our 3/4 and full wave aerials if we go data?
Is it an interference problem or something else?
Hello Andy,
I dont recommend magmounts. The best antenna to fit to a vehicle is a bodymount antenna on the roof of the vehicle. This gives you the best earth and also the best signal from the vehicle, BUT, some drivers dont like holes being drilled in thier cars so we have too look at other types of antennas:
Bootclip - This will fit on the lip of most car boots. The antenna base has a small "U" type lip which fits over the cars boot edge and then secured by screwing in two small screws. The problem with this antenna is that the cable bends round the bootlip and eventually the cable can get breaks in it. It is also fitted at the back of the vehilce and as such does not give the best signal pattern. Good point is that you dont have to drill vehicle and if you change vehicle you can take it with you.
Glassmount - Two part antenna which sticks on the car window (either read or side window). Its the same idea as you see with the mobile phone antennas. Problems is that it can fall off if it is not correctly fitted. Good points is that it can be used on fiberglass vehicles as it does not need an earth. You can only get them for Midband/Highband/UHF. They are also exspensive compared to other types of antennas.
Magmount- The drivers mate. The main problem is that the cable has to pass through either the door of the vehicle or the boot. This is where the cable can get broken and once you get water into the cable then the antenna is no good at all. It can also cause problems to the paintwork with stratching and if you leave it in the same place for long enough it will discolour the paintwork.
Bodymount - This is the best antenna that you can fit to a vehicle as long as its fitted in the correct place. Best place is on the roof. Good signal pattern from it. Downside is that you have too drill a hole in your car but you can easily put a small mobile phone antenna on the mount when you come to sell the car as the majority of drilled mobile phone antennas use the same mounts. Some people drill the back wing of the vhehicles. This is the WORSE place to put your bodymount antenna.
I hope that gives you an idea about the various antennas on the market.
As for 3/4 lenght antennas. I dont like these types of antennas. THey are supposed to have a "gain" on them but if they do then if you follow your radio licence scheudle to the letter, the radio used in these vehciles should have their power turned down to composate for the gain in the antenna.
Next, a bodymount antenna installed properly on the roof (16 1/2 inch for high band and 17 1/2 for midband) will work just as well if not better than a 3/4 wave antenna stuck on the roof. I have changed a lot of cars over from these so called HIGH Gain antennas to the 1/4 antennas and the results have been very good.
I personally dont like these types of high gain antennas and I beleive that radio dealers are just trying too get a little more out of the driver. If a company is having to use these antennas then they are trying too compensate for a badly engineered radio system. They would be better spending money on the main radio site and proper installations of the vehicles.
Well Andy, I hope that this has answered your questions.
Radioman