User's Manual

When examining large frequency segments, it is common to find that 90% of the

frequencies are inactive and only a small number of the remaining constitute what

you really want. Searching still remains the best way to initially locate active and

interesting transmissions (in conjunction with a good frequency listing and band

plan).

SCAN: Once active transmissions have been identified (either by searching or by

using a good frequency guide), it is more efficient to store the data into memories

which can be rapidly and automatically monitored in succession, stopping when

activity is encountered. This is a much more efficient means of monitoring the

most wanted frequencies as you have targeted 100% of what you most want to hear.

By contrast, searching is very inefficient for day-to-day monitoring.

Note: For the search & scan functions to operate properly, it is very important

to advance the squelch to cancel background noise. This is because the

AR5001D believes that it has found an active frequency when the squelch opens

and the “BUSY” indicator lights up. Advance the squelch control clockwise until

the background noise is just cancelled; this is known as the “threshold” position.

If the squelch control is advanced too far, weaker signals may be missed.

More details about the remarkable features of the AR5001D

High frequency (45.05 MHz) IF output

The AR5001D has a 45.05 MHz analog IF output with 15 MHz bandwidth. The input signal to the 45.05

MHz IF stage is directly sent to the A/D converter for digital processing. This IF output signal may be

suitable as an RF front end for radio signal analysis applications. By utilizing this feature, no image signal

will be present. With an optional interface unit, a USB 2.0 interface digital I/Q output is also available. The

raw data of the I/Q output may be recorded on a PC for future analysis.

High Stability Frequency Standard

When an optional GPS unit is connected, the internal reference oscillator (10 MHz) will be locked by the

GPS receiver, and the highest stability reference signal (0.01 ppm) will be obtained. This is ideal for

frequency coherent operation and DF (Direction Finding) applications.

DDS (Direct Digital Synthesizer)

The AR5001D uses a high speed DDS for the 1

local oscillator. Unlike a standard PLL (Phased Locked

Loop) circuit for the local oscillator, the DDS enables very high speed scanning as it generates signals

instantaneously, controlled by the CPU (Micro Processor).