Astronics Test Systems

APPLICATION NOTE

Setting up Astronics R8x00 P25 Trunking Simulator for Motorola Radios

STEP 1 – BANDPLAN SETUP (THIS STEP APPLIES ONLY IF BS MODE SET TO IMPLICIT)

Navigation: P25 Trunk Zone > More > More > Bandplan Table...

P25 Trunk Bandplan Configuration

Parameter	Value	Parameter	Value
BS Mode	Implicit	Gen Mod Type	C4FM
WACN ID	BEE07 H	Voice Call	Idle
WUID	000001 H	SYSTEM ID	40F H
WGID	0001 H	RFSS ID	04 H
Band	800 MHz	SITE ID	04 H
CCTX	1513 860.462500	Iden Update	OFF
VCTX	1293 859.087500	Sym Dev	2681.4 Hz
Mod Fidelity	33.22%	Sym Rate Err	0.37 mHz

Bandplan Setup Parameters:

Band: Select Band, then "Set Band Plan to Defaults".
Bandwidth: Navigate via CPS > Trunking System > Astro 25 Channel ID > Channel Bandwidth.
Base Frequency: Navigate via CPS > Trunking System > Astro 25 Channel ID > Base Frequency.
Channel Spacing: Navigate via CPS > Trunking System > Astro 25 Channel ID > Channel Spacing.
TX Offset: Navigate via CPS > Trunking System > Astro 25 Channel ID > TX Offset.
Channel ID: Navigate via CPS > Trunking System > Astro 25 Channel ID > Position: Channel ID #.

ASTRO 25 Channel ID Configuration

A table detailing channel IDs, frequencies, and spacing:

Site Alias	Advanced	Channel ID Number	Transmit Offset (MHz)	Channel Spacing (kHz)	Base Frequency (MHz)
700_800_900 Control	700_800_900 ASTR	1	45.00000	6.250	851.00625
700_800_900 Control	700_800_900 ASTR	2	30.00000	6.250	762.00625
700_800_900 Control	700_800_900 ASTR	3	45.00000	6.250	851.00625

Press the ESC key to exit the Bandplan Table.

STEP 2 – TX FREQUENCIES SETUP

Configure Control Channel and Voice TX Frequencies. If BS Mode is set to Explicit, setup RX frequencies as well.

P25 Trunk Band Plan Summary:

Band	800 MHz
Bandwidth	6.25 kHz
Base Frequency	851.006250 MHz
Channel Spacing	6.250 kHz
TX Offset	-45.000000 MHz
Channel Identifier	1

Control Channel and Voice Channel Configuration

CCTX: Navigate via CPS > Trunking System > 700_800_900 ASTRO 25 Control Channels.
VCTX: Navigate via CPS > Trunking System > 700_800_900 ASTRO 25 Control Channels or set to any value in the bandplan.

Once TX frequencies are entered, the corresponding channel number is calculated. Alternatively, you can enter the channel number and the frequency will be calculated.

Formula: Frequency = Base Frequency + ( Channel Number X Channel Spacing )

Example: 860.4625 MHz = 851.00625 MHz + ( 1513 x 6.25 kHz)

The simulator automatically sets the Mon Freq and Gen Freq in the RF Zone. The simulator generates the control channel signal at Gen Freq and listens for a radio's affiliation request at Mon Freq. When a radio is keyed, these frequencies change to the Voice Channel for the call duration. This behavior can also be observed when a Voice Call is manually initiated from the analyzer.

RF Zone Frequencies:

Control Channel	Mon Freq: 815.462500 MHz	Gen Freq: 860.462500 MHz
Voice Channel	Mon Freq: 814.087500 MHz	Gen Freq: 859.087500 MHz

STEP 3 – ID SETUP

System and Network Identification:

System ID: Navigate via CPS > Trunking System > General > Home System ID.
WACN ID: Navigate via CPS > Trunking System > General > Home WACN ID.
NAC: Same as System ID (for Motorola systems).
RFSS ID: Navigate via CPS > Trunking System > ASTRO 25 Site Alias > Rfss Alias Num.
SITE ID: Navigate via CPS > Trunking System > ASTRO 25 Site Alias > Site Alias Num.

ASTRO 25 Site Alias Configuration

A table detailing site aliases and associated IDs:

Site Alias	Advanced	Site Alias Num	Site Alias Txt
FREEPORT	Site	00001	001
GLENWOOD	Site	00001	001
HOFFMAN	Site	00001	001
KIMBALL	Site	00001	001
FINIGOL		00001	004

Meter Zone Status and Call Initiation

Once the analyzer is set up, the status is visible in the Meter Zone. 'Idle Control Channel' is displayed until a radio attempts to affiliate. A rapid sequence of status messages will appear. Radio ID information, such as Unit ID and Group ID, will be displayed in the Meter Zone. The squelch level may require adjustment.

Meter Zone P25 Trunking:

Status	Idle Control Channel
WACN ID	00001 H
SYSTEM ID	001 H
UID	000001 H
GID	0001 H
WUID	000001 H
WGID	0001 H

A call alert can be initiated to the radio, or a voice call can be started/stopped. A 1 kHz tone will be heard from the radio.

Call Control: [Voice Call Button] [Stop Button] [Start Button] OR [Send Call Alert Button]

When the radio is keyed for several seconds, it moves to a voice channel and the signal is recorded. Upon unkeying, the analyzer transmits the signal back to the radio, allowing you to hear your voice in the radio. This "Voice Loopback" functionality works even if the channel is encrypted. After the call, the simulator returns to Idle Control Channel mode, awaiting the next call.

The analyzer supports three modulation types: C4FM, LSM, and WCQPSK. LSM and WCQPSK are used in simulcast systems.

It is recommended to save your configuration as a PRESET (Test > Presets) for easy access by technicians.

EXPLICIT MODE

When P25 trunking system channels do not fit a bandplan, radios must be pre-programmed with a channel list, as frequencies cannot be computed from a base frequency and offset multiplier. This is common for P25 systems in VHF and UHF bands where frequencies are scarce.

To simulate such a system, the analyzer's Base Station Mode must be set to Explicit, requiring additional setup. Since TX and RX frequencies cannot be defined as offset pairs, Control and Voice Channel RX frequencies must be provided along with TX frequencies.

By reducing the Output Level in the RF Zone, radios can be tested in a weak signal environment to determine their affiliation threshold.