Car mounted antenna

drnazo · 06-01-2002

Lullabud told me that he was buying an outside mountable car antenna. Well, it got me thinking. Why buy an outside mountable antenna when you can build your own?
I've had nothing but good results from the pringles can antenna I made and I had been planning on mounting it outside of my car. My first I idea was to mount it on the passenger side window outside of the car. I then threw that idea away, or at least postponed it for now.

The new design that I have is to mount it on top of my car magnetically. Not original but practical I guess you could say. I just bought the stuff I need today at Home Depot and soon I will be putting it together. I'm going to include it to my current web journal for the pringles antenna when I'm done. It's quite a stretch from what I originally thought that it would be but when you start modifing the design based on materials that you see while walking through the store it can evolve. Kind of big but I figure that if people are willing to drive tiny hondas with spoilers half the size of their cars and neon green rims with lights on them, I'll do just fine.

My main reason for starting this thread is because I want to know what kind of antenna mountings that you guys have on your cars. I'm also quite interested in the homebrew car mountings and how you built them.

lincomatic · 06-01-2002

the pringles is too directional for stumbling though...you'll miss tons of AP's w/ its tight beam. you're better off using an omni to find the AP's and using the pringles to zero in on a particular one.

anyway, if you want to mount it in the car, having it inside shouldn't degrade your gain too badly since it's so directional...unless you have a windshield that blocks microwaves like some of the benz's have.

just point it thru your windshield.

drnazo · 06-01-2002

Actually, the pringles can antenna is more omni directional then what I thought it was going to be. I would say that it is 30% omni and 70% uni. I think it's because the inside wall of the can is not real metal or metal foil so it absorbs more from the sides then if it was metal. The cantenna is quite uni-directional because it's all metal and I wouldn't suggest that for wardriving. I've tried basic omni's vs. the pringles can, depending how it's angled, can pick up more APs. If you angle the pringles can at 45 degrees from the center of your car towards the right (depending on what country you're from) with the collector element horizontal you can pick up a lot of APs on either side of the road.

There is quite a bit of signal degradation if it's inside of the car rather then on the outside. I tried connecting to an AP 3 ways. The first way is Winter style, that is with all of the windows up and inside of the car. This proved to provide the lowest of the three signals. The second was having it propped between the headrest and seat as with the "Winter style" but this way is with the passenger window opened. This is much more effective. I tried the opened and closed window techniques in a buick, honda, and mercury all with similar results. The third was having Lullabud driving and me sticking the antenna out of the window about a foot or so away from the car and holding it by hand. This was the best one. I found 30% more APs doing this.

I've been experimenting with other stumblers on what materials degrade the signal. Metal is one of the big ones for obvious reasons. The second is glass. I noticed that both auto glass and building glass degraded the signal. The bad thing is that while in a car, this is what you're surrounded with.

I don't have exact records of this but I will once I build the outdoor car mount and when I get a new pigtail since the pigtail I have now had detached from the n-connector and hasn't been the same since.

lincomatic · 06-01-2002

i've never tried the pringles myself, but i'd heard that yagis are very directional...that's supposed to be why they have such good gain.

that must look pretty weird w/ you sticking your antenna out the window. wonder what a gendarme would think if they saw you...

drnazo · 06-01-2002

I considered it a yagi at first too but after talking to old wise men of antennas and also from reading what they have written about this I don't consider it a yagi anymore. Well, they don't consider it a true yagi. They said that it was yagi-like but the way that it's built keeps it from being a yagi. I'm new to all of this so I can't really tell you why it's not. If I had the url still I would post it because I would even like to read it over again.

I do think that if you were to use a real yagi built by the pros it would be almost completely uni-directional.

Funny thing you mention that it looks funny with my arm holding what many have described to look like as a pipe bomb. I was latching onto a network from a parking lot outlet in the winter and was trying to get a good signal. Here I was in a buick that looks like an undercover police car with a round black object pointed towards the street from my windshield. I couldn't believe all of the people driving past that immediately hit their breaks to slow down to the posted speed limit once they seen me.

lincomatic · 06-02-2002

how about strapping the antenna to a speaker magnet and mounting it on your roof? they are pretty powerful. of course you now you have a missile launcher on your roof...still looks kind of suspicious. a more discreet way would be to get one of those fiberglass cases people use to store things on their roofs (man that word doesn't look right ... "rooves?" LOL) and use that as a radome.

drnazo · 06-02-2002

Oh, it really will look missle like. In fact I'm going to glue a black funnel to the front of it to make it more aerodynamic. I hope people don't think that I've gone JIHAD or something.

ZipperSeven · 06-02-2002

I have to agree with drnazo, when stumbling with the pringles, we found that we can pick up an AP at alomst any angle, though it really is stronger (but only by a little) from the front, and oddly, from the back as well. It's starting to make me wonder if that design really works because there's just a piece of copper plugged into the pigtail, or the internal structure really does tune the signal.

As to car mounts: personally I would think that if you're going to mount something outside, why not just build an omni? A little piece of metal sticking up with a twist in it looks like a cell antenna and less threatening than a black can. Perhaps the LEO's are more lenient where you are, but here we have the Campus police, Capitol police, sheriffs dept., local city police, DOT officers, and highway patrol. Whew!

drnazo · 06-02-2002

We have a lot of law enforcement here too. I just won't go on a millitary base with it. I was thinking about building an omni. I might still. I've wanted to make a car mount for the pringles can antenna for some time now so I figured I would do that and then take what I learned from that to build an omni.

06-01-2002	#1 (permalink)
drnazo I'm special Join Date: May 2002 Location: CO / Springs Posts: 29	Car mounted antenna Lullabud told me that he was buying an outside mountable car antenna. Well, it got me thinking. Why buy an outside mountable antenna when you can build your own? I've had nothing but good results from the pringles can antenna I made and I had been planning on mounting it outside of my car. My first I idea was to mount it on the passenger side window outside of the car. I then threw that idea away, or at least postponed it for now. The new design that I have is to mount it on top of my car magnetically. Not original but practical I guess you could say. I just bought the stuff I need today at Home Depot and soon I will be putting it together. I'm going to include it to my current web journal for the pringles antenna when I'm done. It's quite a stretch from what I originally thought that it would be but when you start modifing the design based on materials that you see while walking through the store it can evolve. Kind of big but I figure that if people are willing to drive tiny hondas with spoilers half the size of their cars and neon green rims with lights on them, I'll do just fine. My main reason for starting this thread is because I want to know what kind of antenna mountings that you guys have on your cars. I'm also quite interested in the homebrew car mountings and how you built them.

06-01-2002	#2 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	the pringles is too directional for stumbling though...you'll miss tons of AP's w/ its tight beam. you're better off using an omni to find the AP's and using the pringles to zero in on a particular one. anyway, if you want to mount it in the car, having it inside shouldn't degrade your gain too badly since it's so directional...unless you have a windshield that blocks microwaves like some of the benz's have. just point it thru your windshield. __________________ ~lincomatic

06-01-2002	#4 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	that's interesting info i've never tried the pringles myself, but i'd heard that yagis are very directional...that's supposed to be why they have such good gain. that must look pretty weird w/ you sticking your antenna out the window. wonder what a gendarme would think if they saw you... __________________ ~lincomatic

06-02-2002	#6 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	how about strapping the antenna to a speaker magnet and mounting it on your roof? they are pretty powerful. of course you now you have a missile launcher on your roof...still looks kind of suspicious. a more discreet way would be to get one of those fiberglass cases people use to store things on their roofs (man that word doesn't look right ... "rooves?" LOL) and use that as a radome. __________________ ~lincomatic

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06-01-2002	#3 (permalink)
drnazo I'm special Join Date: May 2002 Location: CO / Springs Posts: 29	Actually, the pringles can antenna is more omni directional then what I thought it was going to be. I would say that it is 30% omni and 70% uni. I think it's because the inside wall of the can is not real metal or metal foil so it absorbs more from the sides then if it was metal. The cantenna is quite uni-directional because it's all metal and I wouldn't suggest that for wardriving. I've tried basic omni's vs. the pringles can, depending how it's angled, can pick up more APs. If you angle the pringles can at 45 degrees from the center of your car towards the right (depending on what country you're from) with the collector element horizontal you can pick up a lot of APs on either side of the road. There is quite a bit of signal degradation if it's inside of the car rather then on the outside. I tried connecting to an AP 3 ways. The first way is Winter style, that is with all of the windows up and inside of the car. This proved to provide the lowest of the three signals. The second was having it propped between the headrest and seat as with the "Winter style" but this way is with the passenger window opened. This is much more effective. I tried the opened and closed window techniques in a buick, honda, and mercury all with similar results. The third was having Lullabud driving and me sticking the antenna out of the window about a foot or so away from the car and holding it by hand. This was the best one. I found 30% more APs doing this. I've been experimenting with other stumblers on what materials degrade the signal. Metal is one of the big ones for obvious reasons. The second is glass. I noticed that both auto glass and building glass degraded the signal. The bad thing is that while in a car, this is what you're surrounded with. I don't have exact records of this but I will once I build the outdoor car mount and when I get a new pigtail since the pigtail I have now had detached from the n-connector and hasn't been the same since.

06-01-2002	#5 (permalink)
drnazo I'm special Join Date: May 2002 Location: CO / Springs Posts: 29	I considered it a yagi at first too but after talking to old wise men of antennas and also from reading what they have written about this I don't consider it a yagi anymore. Well, they don't consider it a true yagi. They said that it was yagi-like but the way that it's built keeps it from being a yagi. I'm new to all of this so I can't really tell you why it's not. If I had the url still I would post it because I would even like to read it over again. I do think that if you were to use a real yagi built by the pros it would be almost completely uni-directional. Funny thing you mention that it looks funny with my arm holding what many have described to look like as a pipe bomb. I was latching onto a network from a parking lot outlet in the winter and was trying to get a good signal. Here I was in a buick that looks like an undercover police car with a round black object pointed towards the street from my windshield. I couldn't believe all of the people driving past that immediately hit their breaks to slow down to the posted speed limit once they seen me.

06-02-2002	#7 (permalink)
drnazo I'm special Join Date: May 2002 Location: CO / Springs Posts: 29	Oh, it really will look missle like. In fact I'm going to glue a black funnel to the front of it to make it more aerodynamic. I hope people don't think that I've gone JIHAD or something.

06-02-2002	#9 (permalink)
drnazo I'm special Join Date: May 2002 Location: CO / Springs Posts: 29	We have a lot of law enforcement here too. I just won't go on a millitary base with it. I was thinking about building an omni. I might still. I've wanted to make a car mount for the pringles can antenna for some time now so I figured I would do that and then take what I learned from that to build an omni.