Close Call™ RF Capture Technology: An Overview with Launceston Signal Examples

Close Call™ RF Capture Technology is a Uniden-specific feature designed to instantly detect and tune into nearby radio signals. This feature works by identifying signals from transmitters in close proximity and can run on its own or in the background while scanning. Close Call is similar to the Signal Stalker feature on some Radio Shack (RS) models and acts almost like a frequency counter, tuning into strong signals that are detected above a certain threshold.

The main idea behind Close Call is to capture signals that are “close” in distance to the user. While it may not detect signals frequently, any hit received is likely from a nearby transmitter, making it particularly valuable for hobbyists tracking down local transmissions.

How Close Call Works
For Close Call to pick up a signal, the signal strength needs to be approximately 15–18 dB above the RF noise floor of the specific band. Various factors influence the range within which a signal might be detected, including:

• RF Noise Floor: Lower noise floors generally increase range, as they make it easier to pick up weaker signals.
• Transmitter Power: Higher power output typically increases the range of detection.
• Antenna Quality and Placement: An optimized antenna can improve Close Call’s effectiveness by preselecting within the desired band and reducing interference from other bands.

In practice, here’s what Close Call might pick up:

• A 1W portable transmitter could be captured up to about 30 meters.
• A 4W portable transmitter might be detected around 75 meters.
• A 25W mobile transmitter may be detected up to 1 - 2km away.
• A 100W base station could be captured from up to 5km away, depending on conditions.

The specific range Close Call can achieve is influenced by environmental factors, antenna tuning, and signal power. For example, in high-traffic RF environments like busy airports, the feature may struggle to distinguish between overlapping signals.

Examples of Signals Detected with Close Call in Launceston, Tasmania
In Launceston, Tasmania, Close Call has proven to be an effective tool for picking up a range of interesting signals from nearby sources. Here are a few examples of signals logged recently:

Railway Maintenance Crew – A signal around 157 MHz revealed a brief transmission from railway maintenance workers operating near Launceston’s rail yards.

Local Events and Venues – While scanning in the vicinity of a local stadium, Close Call picked up security and event staff communications on UHF frequencies, adding an extra layer of situational awareness.

Using Close Call in Launceston has enabled a more in-depth exploration of nearby signals, giving insight into local communication networks and activities. This tool can help monitor and analyse nearby broadcasts, especially when combined with knowledge of typical frequencies used by various services.