What type of antenna?

Ok i've read all these posts and still a lil confused. I have a radio shack multitrunking scanner that came with the rubber antenna. The only time that antenna is on the scanner is if im out walking around with the camera. Other then that the scanne is in my cupholder with a magnet antenna on my roof. The antenna barely screwed into the base and is about 8" long. I bought a new antenna from radio shack that mounts to the window/windshield. Im not sure how exactly it sends the signal thru the glass to the other piece with the wiring for the scanner. But the antenna itself is about 2 feet long, give or take a few. Will I notice a big difference once I hook this antenna up and have it mounted to the top most portion of my trucks rear window?

Your mag mount will have a LOT better ground plane on the roof than ANY window mount antenna.

no the thru the glass antennas, suck. buy a radio shack adjustable (adjust it to about 17", more or less is not good), on a mag mount, put it in the center of the metal roof. Most or many of the posts are only semi-accurate.. The best antenna is a dipole which is 1/2 wave long and fed in the center. The 17" "antenna" is 1/2 of that dipole, and requires a 17" long radio or the roof of a car to complete the dipole. Anything else will work "no so well".. The 5/8 antenna is somewhat better, but starts to degrade when trying to recieve signals arriving from above the horizon. The thru the glass antennas have considerable loss thru the glass and rely on the coax (inside the vehicle) for the other half of the antenna. There is no silver bullet or majic manufacturer.. Ed

well this sucks. I wish i had checked on here first before I mounted the window antenna on my rear window. The mast is 24" long if that makes any difference.

Window mounts just plain suck, no ground plane. Go back to the mag mount, place it dead center on roof or trunk lid and you'll be just fine. (Authorized Motorola radio Dealer)

out of curiosity, why do the window mounts suck?

Steve F45 wrote:out of curiosity, why do the window mounts suck?

Three reasons come to mind.

(1) capacitive coupling through the glass has some loss.
(2a) effective groundplane is directional, better in the direction of the adjoining roof, worse in the other directions.
(2b) in the directions without a groundplane, the radiation/reception pattern is a very high angle. Good for listening to airplanes in flight and space satellites, but not for terrestrial stations like railroads.

Ken is of coarse correct, but it is not so much that they suck, they do work. It is just that they are so far inferior to a simple 17" in the center of the roof . Years ago I bought one since I had a conversion van without a metal roof. I replaced it with a mag mount on the hood of the van, and then tried a hustler on the rear ladder, and finally ended up with a jpole growing out of the top of the ladder, the best so far, but they all, basically, suck compaired to the simple 17" thingy in the center of the metal roof I dont have...

Greeeeaaaaaaaaaaat. Now I wish I didn't throw away the mag base. Looks like I'll be checking out some new mag base. One of hte reasons I bought the glass mount was, 1. Thought it was better then my mag base. 2. Didn't have to remove it everytime I went into low clearence places or car washes 3. longer antenna.

Actually, you can go one better. DRILL a hole in the center of the metal roof of your car and mount an "NMO" into it. NOW, you can "borrow" an antenna from just about any of the police cars in the country, they are cut to about 155mHz and will work just fine for you on 162... (they just unscrew, dont forget to return it)... GBG................. actually, if you are a purist, the 17" number may be a little off depending on they physical construction of the mag mount. Locate a local ham who can measure the VSWR of the thing, you may want to do some trimming. Word of caution from one who has been there: cutting it longer doesnt work too well..... BTW, longer is not gooder, antennas are freq sensitive devices, making it longer, or shorter, than the 1/4 wave 17" will degrade its proformance..preformance??? whatever.... Ed

No drilling in my roof. I'll have to check out a few radio stores for a decent mag mount. It does seem that my reception actually has gotten worse. I wasn't to far away from a local train crew drilling some cars when I started to loose reception whereas the roof mount i would hear them from where I was.

Popular thought not withstanding: Drilling a hole in the roof of a car is NOT the same a raping a virgin, and one who thinks it is should leave technology for the arts or somewhere. I drilled a 3" hold in the roof of my brand new (for me) '57 Chevy for the mast of a hidden transmitter antenna to grow out of, and started winning the hunts.. But that was before I was married and was still capably of logical thought.. GBG
Ed

here's a question. What about using the original car antenna? I have satellite radio and dont listen to the regular radio anymore. Is it possible to use the original antenna or atleast hook it up to a scanners antenna wire? would this work?

they are "cut" for the broadcast band, most have some kinda micky mouse inductance in their coax, and they have a motorola male plug on 'em. try it, the worst it can do is not work . . . . why are you guys fighting this?? you can use a 17" wet noodle.. Ed

not trying to fight it. my roof already got scratched to hell from the last roof mount antenna. It never stayed in the place I put it. So i didn't want to have to go that route again, hence why i got the window mount and then asked about using the original radio antenna. i'll just give in and get a new roof mount, hopefully find one a little stronger that wont slide around and chew up the paint.