Specifications
- Antennas should be single band, narrow bandwidth, and tuned to 161 MHz. Typical wideband scanner antennas, such as discones, allow far too much of the radio spectrum in.
- A properly tuned, narrow bandwidth antenna not only increases reception on the intended frequencies, it also helps reject nearby strong signals on other frequencies.
- Commercial-grade antennas are preferred. Amateur radio, scanner, & many home-built antennas do not have the same performance or longevity as commercial-grade antennas.
- Builders of amateur radio, scanner & many home-built antennas tend to exaggerate their gain figures, whereas commercial builders tend to be more conservative – ensuring you get the performance you paid for.
- Commercial builders use better quality materials & design a more durable product, ensuring that the antenna performs as intended for much longer.
- Commercial builders have better quality control procedures in place and test their products more thoroughly.
Preferred Models
|
Model |
Usage |
|---|---|
|
Preferred omnidirectional model. |
|
|
Alternate omnidirectional model. Can be hard to find. |
|
|
Indoor omnidirectional model, when mounting outdoors is impossible. |
|
|
Used when broad directional or bi-directional gain pattern is desired. Multiple possible configurations. |
|
|
Moderate gain in one specific direction. |
|
|
High gain in one specific direction. |
Antenna Principles
- Height is might.
- Increasing the height of an antenna is the single best way to improve reception. While a higher gain antenna can help, simply increasing the height of the existing antenna even just 10′ often makes a bigger improvement.
- Do not rely on preamplifiers to increase reception. They often do more harm than good, and should not be viewed as a “quick fix” to increase reception.
- Make the gain pattern work for you.
- While omnidirectional antennas have their place, do not automatically purchase them without giving it any thought. Directional & bidirectional antennas can yield more gain for the same relative size, providing better reception for the subjects you want to listen to (the trains).
- If only listening to one specific direction, a Yagi antenna pointed in that direction will be the most effective.
- For feeds along a rail line that need coverage in both directions, a folded dipole antenna set to a bidirectional pattern will be most effective. Many Class I railroads use these antennas on their dispatcher bases and defect detectors for this exact reason.