I've seen these scanners in radio shack. Would getting a corded model and a HUGE ass antenna, let you scan across town/s ?
Longer antennas don't necessarily mean better reception. It's far more important that the antenna be the
proper length for the frequencies you're working. Antennas perform at optimal efficiency when they're "tuned" to the wavelength you operate on.
Tuning means cutting or fashioning the antenna to a length that is directly proportional to the wavelength you're trying to receive or transmit, or some fraction thereof. There are full-wave antennas, half-wave, quarter-wave antennas, etc.
Probably the single most important factor in antenna performance however, is elevation. VHF and UHF frequencies' wave propagation is "line-of-sight," which means that the radio waves must have a relatively unobstrcuted path between the source and the receiver. For this reason, VHF and UHF cannot propagate very far beyond the horizion. Therefore, the higher your antenna is placed, and the more in-the-open it is, the better your receptions and transmissions will be.
For a cheap, easy-to-construct antenna for scanner and ham radio operations, you'd most likely be using a "dipole" design. Dipoles are very simple, basically just a couple pieces of copper wire cut to the proper lengths and attached to a shielded feed cable in the center to form a "
T" shape.
This Wikipedia page describes dipole antennas and includes a diagram illustrating their construction as well as the formula for calculating the lengths of the elements. As you can see, these are very simple to make.
You can also make a shorter "monopole" antenna by eliminating one of the elements of the dipole and in its place soldering on a "ground plane" which consists of few square inches of 1/16" thick copper sheeting. The remaining element should be arranged in the center of the ground-plane and at a right angle to it.
If you want to operate on more than one band you'll need to have either a different antenna for each band, or a dual- or multi-band antenna. Building a multiband antenna can get rather complicated. For more detailed information on antennas including some plans for their construction, visit:
http://www.antennex.com/guests.html. (You'll need to register an email addy with them before you can access any of their information).
Once you've fashioned the antenna, you want to install it in a very high place. The higher the better. An optimum situation is a point high above any other large structures in your area. The most common method for ham radio antennas is to mount them atop a tall mast or tower. Some other good, practical options are to hang it inside your attic, lay it across the roof and secure the ends or suspend it from the highest tree in your yard.
To hang the antenna in a high tree, get a roll of twine or clothesline, attach a rock or weight and throw it as high as you can over the top branches of the tree. It may take a few tries, but the idea is to loop it over the highest sturdy tree branch that you can manage, yet still allowing it to fall back within grabbing range. Then simply attach one end of the cord to your antenna element, grab the opposite end of the cord and use the branch as a pulley to hoist the antenna way up into the tree. You'll probably have to do some creative maneuvering to get the antenna properly arranged in a high tree, but it's well worth the effort if the antenna is successfully placed way up in the air.
A well-tuned antenna placed very high above its surroundings will give you the best possible reception and the best range for the wattage of your transmitter.
