Glass Antenna - Is it effective ?

[mclaren1885]

Originally Posted by Sam Kapasi

However in the case of the verna, the antenna is on the roof rear, where the shark should be.

If I replace my existing antenna with the shark kind, do you think that will affect my reception? Or should I try it and let you guys know?

Its funny that ICE guru is asking us this rather than giving us the solution. Comeon yeti.

[BUSA]

@ Sam - The reception would be the same but you would have to make the shark antenna replace the stock one.

[navin]

Originally Posted by Sam Kapasi

However in the case of the verna, the antenna is on the roof rear, where the shark should be.

same as in opel and skoda. No it wont affect your reception atleast it did not make a difference in a opel corsa someone from my family had. the original antenna was stolen so we installed a shark and it works as good as the original. BTW it is better described as a shark fin (no not the vodka).

[abhilashvk]

[huge, motorized, extending above boot in sedans. A few high end cars have it tilted backward; what purpose doest it serve?]

Should be tilted so that there is no air resistance at high speeds. My Accent's motorized antenna have tilted outwards with time because of air resistance, so for many other Accents, I have noticed.

[tsk1979]

Sam, a long straight wire(4-5 feet long is a good idea) makes a Decent FM antenna for strong stations. Thats why your Nokia phone, or non creative nano players etc., which have FM use the earphone cable as an antenna.
However if the reception is not very good, or there are lots of reflections, in lets say a street with high rise buildings etc., you need to go a little technical. But still nothing you cannot DIY
The glass antenna, the rabbit ear antenna(Remember old TVs?), the Tata indica antenna are all "Dipole antennas".
Below I will try to explain to you how to make a nice dipole antenna. Its similar to the glass antenna, but design is better. You will find the design on numerous websites too, each having a different goal(HAM etc.,). Below is what was tried way back in college.
1. Take a 300ohm wire. In Radioshack USA it was called the lead in wire. I am sure you audio shoudio guys will know the exact terminology. Its basically two copper wires running parallel to each other Cut it to 4 feet 11" length. At both the ends cut away 1" of insulation. So now you have a 4'9" length of wire covered in insluation and 1 inch exposed at each end. Tie the wires at the end together and cover with tape. You have your dipole now.
2.Now cut the dipole in the middle as shown in figure, and this goes to HU, see figure



There, you have a nice antenna.
Now lets talk about manufacturers.
First Tata indica. The dipole antenna is very very small. FM is 3(98MHz) meter wave,
Without going into technicalities, you need to take 468 and divide by freq in MHz(Taken from TV engineers handbook). So if you listen more to 91, 92Mhz you can make your antenna longer(5 feet) but if you listen to FEVER 104 and only fever 104, then make it 4 feet 6 inches. Make sure you leave one inch at each end, we folded that remember.
Thats the reason when I switch on the AC, 104FM plays okay but the 95FM is patch, 91FM is even worse sometimes. That antenna is good for 300Mhz I think.
Then the glass antennas. Since they are part of the heating mechanism(I salute that engineer) everything gets messed up.

So sam you are a DIY guy go ahead and make it.
As for omni-directional antenna you can make a folded dipole antenna or turnstile antenna, but they are not conducive in a car, unless you want it too look like a bat mobile.
Last but not the least, remember those old TV antenna's with rods parallel to each other, that is a Yagi antenna, and very good directional antenna(useless in a car, but best for your home FM)
And many people use a cycle tires in areas of strong reception to make good omni directional antenna

[tsk1979]

another thing I forgot the add, remember the days before satellite TV when you had that black ribbon cable doing to antenna? Thats a 300 ohm lead in cable. Cost is around 5rs a meter.

[navin]

TSK, I can see that now. Sam in his jeep with one hand holding the 5 foot long antenna like the Statue of Liberty. If that dont get him arrested nothing will.

[tsk1979]

Originally Posted by navin

TSK, I can see that now. Sam in his jeep with one hand holding the 5 foot long antenna like the Statue of Liberty. If that dont get him arrested nothing will.

Navin ji, you can mount it on the windshield, just like in the indica, only thing is that instead of extending half a feet on each side, it will extend 5 feet, almost to the end of the windshield.

[anonymous]

Originally Posted by kartikkumar

Good question. I had problems with the glass antenna on my Indica. Even on open roads the signal for certain FM channels was weak and I would get a lot of crackle. While it may allow for no protrusions, I think the external antenna on the Swift (which I drive now) looks great and works well too.

Any expert views on this?

I have experienced it. When I am far away from delhi, lets say around 100 KM, my indica's internal antenna doesn't not catch any signal of any FM but at the same location, other cars, which have external antennas, pick up singals for every FM. Also in delhi, sometime the reception quality is not very good.

[tsk1979]

Originally Posted by rlather

I have experienced it. When I am far away from delhi, lets say around 100 KM, my indica's internal antenna doesn't not catch any signal of any FM but at the same location, other cars, which have external antennas, pick up singals for every FM. Also in delhi, sometime the reception quality is not very good.

Thats because the indica antenna is too small, you need something atleast 4'6" long. With a big antenna you will be able to get FM even in Panipat and Karnal.

[anonymous]

Originally Posted by tsk1979

Thats because the indica antenna is too small, you need something atleast 4'6" long. With a big antenna you will be able to get FM even in Panipat and Karnal.

Hi tsk,
How can I get this one fitted in indica. Does it have to be internal or external one?

[tsk1979]

See my post, after you make it with your TV antenna wire, just stick it to your windshield, disconnect the old antenna and connect the leads to this one. It is just like your original antenna, but much longer, will run end to end on the windshield

[clipto333]

hi,

nice work there tsk. i have a problem. my OE antena in my accent has conked off(the motor). i hav to get it replaced. with the aftermarket antenna. will the reception be ok? my wife drives the car(i only get the car when i come back form work :((. ) if the reception aint good, she'll force me to buy the OE antenna which is for 5600/- . so what im planning to do is to buy the after market power antenna and diy the antenna you mentioned above(only if it'll work throughout the fm band) and use it instead of the after market antenna. what do you suggest??

cheers
clip

[santosh.s]

Originally Posted by clipto333

hi,

and diy the antenna you mentioned above(only if it'll work throughout the fm band)
clip

To make it work reasonably across the whole FM band, antennae are tuned to the frequency corresponding to the center of the band.

Making an FM antenna is probably the easiest DIY... but wouldn't it look plain ugly?

Another doubt, since glass antenna is surrounded by metal all around (worst in case of defoggers), wouldn't it deteriorate it's performance?

[tsk1979]

The dimensions I have given are for around 98MHz, i.e. bang center of band, 20MHz is fairly narrow, so this antenna will work.
As for the metal part, its better to mount it on front windscreen, but if you use a high end car or have a anti Infrared sun film, it may not work. Reason, many modern high end glass as well as films have lot of metal in them. Thats the reason windshield mounted GPS antennas also do not work well in these cars.
But since mostly people going in for such contraptions drive normal cars, you can just use what I listed.

Now comparing OEM, Aftermarket and DIY antennas, well its just a wire. OEM antennas take aesthetics into play, so they are usually worse off. For example a 1 meter long straight wire will work as a good enough antenna too if you are near a FM station.

So just buy that TV antenna wire, make this antenna, stick it on the windshield. In case of cars like indica which already have a windscreen mounted antenna, all you need to do is disconnect that, and connect the 2 wires to this DIY antenna.