The Sagax SRT-3000 VHF/UHF tuner is a modular building block, which can be used for high-performance surveillance, monitoring receiver applications. The tuner can be used as a stand-alone wide-band front-end for an digital IF software-defined receiver.
The incoming frequency band down-converted to a standard 70MHz IF output. 21.4MHz or 140MHz IF output frequencies are available as an option. The actual frequency and gain can be controlled trough the multi-drop RS-232 interface with some simple published command. (API) The tuner is housed as 1U height standard 19” unit with external 115/230 VAC power supply.

Typical applications

Spectrum monitoring and management systems

Signal intelligence and surveillance systems

Wideband intercepting and monitoring receiver systems

Functional block diagram

The offered VHF/UHF tuner is based on a well proved high-side first IF architecture used by high-grade receivers and measurements devices to provide excellent spectral purity. The triple conversion architecture ensures the usage of lower IF frequencies too. The bandwidth of the modern digital tuners enables to use the standard 21.4MHz/70MHz/140MHz IF frequencies. The choice of used IF frequency depends on the applications. When wide instantaneous bandwidth is required in scanning receiver the 140MHz is available to use the maximum bandwidth, which is available. When narrow bandwidth monitoring reception is required the lower 21.4MHz can be used to implement the bandwidth limitation before the digital filtering to increase the dynamic range.

The input (RF) and output (IF) attenuation can be used for dynamically change the amplification to move the available instantaneous dynamic range in the desired region. The front-end could contain a wide-band pre-filtering for wide-band fast-scanning application or sub-octave, tuned pre-selector for narrow-band monitoring applications. All of the synthesized local oscillator could be locked to an external 10MHz reference frequency to provide a phase synchronous receiving system. The locking time of the high-speed phased locked loops offer as low as 100us frequency step tuning speed for fast scanning applications. The control of the front-end is implemented as multi-drop asynchronous serial interface, but twisted pair Ethernet based IP connection also could be provided.

Product fotos

Typical performance

Performance data

Frequency control
Frequency range	20 – 3000MHz (VHF/UHF version)
Tuning resolution	1MHz synthesized
Internal reference accuracy	+/50 part in 10E6 (-10°C to +55°C)
Internal reference aging	+/10 part in 10E6 /year
External reference frequency	10MHz, 0dBm nominal input level
Local Oscillator Phase noise at 10KHz offset 20-520MHz 20-3000MHz	-90dBc/Hz -85dBc/Hz
Synthesizer settling time	1ms
Antenna input
RF input impedance	50 ohm, nominal
Input VSWR	2.0:1 typical
Sensitivity
Noise figure	12dB typical 20-3000MHz full band

Nonlinearities
Intermodulation 2^nd order intercept point	Typ. +24dBm
Intermodulation 3^rd order intercept point	Typ. +6dBm

Interference rejection
Spurious frequency rejection	70dB, typ. 80dB 20-6000MHz range
Internal spurious signals	-100dBm equivalent input

Gain control
RF gain control	0dB/10dB/20dB
IF gain control	0dB/10dB/20dB

IF output
Output frequency	60MHz (10.7MHz, 21.4MHz, 70MHz and 140MHz are optional)
Output bandwidth	26 MHz (any other optional)
IF output impedance	50 ohm, nominal
Output VSWR	2.0:1 typical

General data

Interfaces
Data interfaces	Multidrop RS-232 or USB
User interface	Published API command set
Operating system	Any

General data
Power supply	External 12VDC 115/230 VAC 50Hz
Power consumption	15W
Packaging	1U 19” (H44mm, W440mm, L260mm)
Weight	3.5kg
Operating temperature	-10°C to +55°C
Storage temperature	-20°C to +65°C