This type of crossband system consists of two transceivers in a Daniels subrack. Receiver A keys Transmitter B only and Receiver B keys Transmitter A only

Frequencies which are within two defined limits. These groupings of frequencies are often referred to by name e.g. 29-50 MHz is called low band. Daniels manufactures radios for the following bands:

The amount of frequency spectrum required to transmit the desired information. Daniels currently manufactures products for two bandwidths.

A transmitter / receiver unit located in a fixed location. Term is often shortened to "base".

A rugged, protective, fiberglass structure built to house the radio equipment and antenna. Due to their ability to withstand strong winds and radial ice build-up, Comshel's ™ are designed for use at mountaintop sites.

A device that causes the repeater to transmit in response to a received signal.

The ability to receive on one band and transmit on another. As an example one could receive on a VHF frequency and transmit on a UHF frequency.

A thin slab of natural or man-made quartz which, when subjected to the proper electrical excitation, will vibrate or oscillate at a specific frequency. A quartz crystal is a major component in oscillators used in radio transmitters and receivers. Crystal oscillators are typically used for low current applications.

Continuous Tone Controlled Signaling System allows a given tone to remotely control radio functions. In some configurations this allows for selective broadcasting. This is accomplished by transmitting an encoded signal with a given tone and decoding it with the receiver. Also known as “PL (Private Line) or Channel Guard”

Digitally Encoded Squelch, a digital version of CTCSS tones.

A device that translates coded tones into usable form.

This type of crossband system consists of two transceivers in a Daniels subrack. Receiver A keys both Transmitter A and Transmitter B and Receiver B keys Transmitter A only. This is a repeater (in the A side) with a switched link (in the B side).

This type of crossband system consists of two transceivers in a Daniels subrack. Receiver A keys both Transmitter A and Transmitter B and Receiver B keys both Transmitter A and Transmitter B. This is a repeater (in the A side) with a repeating link (in the B side).

Dual Tone Multi Frequency. A DTMF keypad allows you to make and receive phone calls through your radio system.

A device that allows users to receive and transmit at the same time.

Ear & Mouth: Separate signal lines for receiver (ear) and transmitter (mouth).

A device that translates tones into a form easier to transmit over a radio system.

A continuous range of frequencies extending between two frequency limits. Common frequency bands in two-way radio are 29-50 MHz (low band), 132-174 MHz (VHF or High Band), 406-470 MHz (UHF), 806 - 869 MHz (800 MHz) and 896 - 960 MHz (900 MHz).

A frequency band including the frequencies at which a system is able to transmit, receive or amplify power.

Facility incorporated in radio receivers to disable their signal output while the received carrier signal level is less than a preset value.

The frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception.

The product of two waves beating together and producing other interfering waves. Sometimes called "intermod" or "IM".

A repeater used to link two or more repeater sites together.

A filter that passes all frequencies below a specified frequency with little or no loss, but strongly attenuates higher frequencies.

The Network Access Code (NAC) is a 12-bit field embedded within every P25 voice call. NACs are primarily used for two purposes:

1. They allow large system coverage areas to be serviced by separate repeaters.

2. They allow multiple repeaters to service multiple systems with overlapping coverage areas.

12.5 kHz bandwidth

A circuit that produces an alternating output current of a certain frequency determined by the characteristics of the circuit components.

Project 25 is a public safety-driven effort to develop digital standards for wireless communications users developed by the Association of Public Safety Communications Officials (APCO) in conjunction with a group of manufacturers including Daniels Electronics. These standards enable critical communications for the safety and security of communities across North America and the world. In emergency situations, Project 25 users can communicate with other agencies and mutual aid response teams. Project 25 wireless mission critical communications user needs include three key digital standard attributes:

Backward compatibility and graceful migration

Project 25 enables system migration which is backward compatible with existing systems, and allows forward compatibility with next-generation radios.

Interoperability

Project 25 enables communication between neighboring systems. This is important for mutual aid where resources are gathered from many different locations.

Spectral efficiency

Project 25 enables 12.5 kHz system migration to 6.25 kHz or equivalent spectral efficiency performance.

P25 Training Guide

In two-way radio systems, the method of communication over a speech circuit in which the talker is required to keep a switch operated while talking. In two-way radio, push-to-talk operation must be used when the same frequency is employed by both transmitters.

A radio station that automatically re-broadcasts radio signals that are received on a specific frequency.

Software used to test and tune the Daniels digital radio modules.

Linear output from the receiver indicating received signal strength as a voltage level.

Squelching mutes the audio output of a receiver. Signal strengths weaker than the squelch threshold are muted in order to exclude undesired lower-power input signals that may be present at or near the frequency of the desired signal. After a receiver has been unsquelched, the audio remains unmuted until the signal strength drops below an even lower level. This is to prevent the audio from cutting in and out. The difference between the squelch threshold level and the lower level is called the squelch hysteresis window.

In a Daniels radio system, Transmitter and Receiver A are on the left side of the subrack, next to the audio control card.

In a Daniels radio system, Transmitter and Receiver B are on the right side of the subrack, next to the system regulator module.

A computer controlled radio system in which many users can share multiple switched repeater equipment while retaining privacy.

25 kHz bandwidth.

A yagi or "beam" antenna is usually used for linking purposes. You may see it polarized in a horizontal or vertical position. A yagi provides increased gain in one direction. See picture above.