J-pole, Yagi, Groundplane?
Brian, All,
The "antenna" you want is a matter of taste. If most of the signals you wish to receive are in a certain direction and no other, then a Yagi-Uda (the REAL name of a yagi) or "beam" antenna is what you want. You can buy these antennas through reputable antenna dealers or amateur radio supply stores. As before, it depends on the frequency you wish to monitor. If it's 800 mhz trunked, the antenna elements (both sides) will be about 6" in length. LTR (400 mhz-trunked) are about 12" long, total and hi-band FM (150-174mhz) will be about 38" long.
Since most of your monitoring, I'm sure, will be in the 800-900 mhz range, you can "Google" to find what you are LQ^QKing for. You won't need "power dividers" or such, as they are used to transmit.
A good, all-around antenna is a "J-pole". Again, GOOGLE is your friend, and there are plenty of plans to build one on the I-net and some are sold by major antenna manufacturers.
A good "groundplane" is another omni-directional antenna and can be made from a UHF, SO-239 female jack. This, as well as the "J-pole" needs to be as high as possible, as they are low-angle receiving antennas (ie. long distance)
The ground plane is very simple to build using an SO-239 UHF socket, some 4/40 hardware, soldering lugs and some #14 guage, solid, insulated wire, although a wire coathanger works well.
I have plans for a "Double-grounded ground plane, which drops the "take-off" angle from the normal 18 degrees to 5 degrees over the horizon. This gives you a greater range distance, but is omni-directional. It picks up signals from all-@round, sometimes not such a good thing. I don't build them to sell them and postal cost being what they are and the lousy service, I can send you a file (no drawings) on how to make one.
My e-mail address is: KA5(dot)LQJ(@)gmail(dot)com <--remove and place the appropiate symbols...used to prevent SPAM, and NOT the "Mystery meat", LOL! SPAM - *Stuff* Posing As Meat...The Society for the Preservation of Amplitude Modulation.
Respectfull submitted,
73,
Don/KA5-LQJ
Grid Sq: EM-32cl
"Downtown Cedar Grove, LA."
