Dual IF/L-Band Satellite Modem


The Q-Flex™ modem embodies a new concept in satellite modem technology - a flexible soft- ware-defined modem that does what you want, now and in the future.

The Q-Flex™ modem’s flexible hardware platform provides IF and L-band operation in one unit. While its powerful processor makes it ideal for handling IP traffic, the Q-Flex™ modem can be fitted with virtually any type of terrestrial interface and will operate at data rates up to 160Mbps.

Flexible pricing is achieved by enabling only the features you need at any time. Future- proofing is assured by convenient software up- grades via Ethernet or a memory stick.


The Q-Flex™ modem supports the most power- ful bandwidth-saving technology available.

Paired Carrier™ overlays transmit and receive carriers reducing satellite bandwidth by 50% (using ViaSat’s patented PCMA technology).

Both DVB-S2, renowned for its robustness and bandwidth efficiency, and its successor, DVB- S2X are supported.

FastLink™ low-latency LDPC is optimised for latency-sensitive applications while giving coding gain that is close to the theoretical limits.

Bandwidth-saving IP features include acceleration and header and payload compression.


Dual IF/L-band operation

Data rates to 160Mbps

XStream IP™ is an integrated suite of ad- vanced IP optimization & traffic management features including TCP acceleration, header & payload compression, dynamic routing, traffic shaping, encryption & ACM

DVB-S2X, FastLink™ LDPC & TPC

Terrestrial interfaces include Ethernet & optical Ethernet, EIA-530, G.703, ASI, OC-3 & STM-1

Optimized spectral roll-offs, including 5%

Paired Carrier™ carrier overlay

LinkGuard™ signal-under-carrier interference detection

Built-in spectrum & constellation monitors

New! DVB-S2X!

New! DVB Carrier ID! Fully compliant with DVB-CID standard!

New! Secure AAA RADIUS login using your normal company network login credentials


Main Specifications




IF: 50 to 90MHz & 100 to 180MHz

(resolution 100Hz) (BNC connector) L-band: 950 to 2050MHz (resolution 100Hz) (N-type connector)

L-band option: Extends L-band operation to 2150MHz

Data Rate

Operation to 2,048kbps provided as standard

Extension options: 5Mbps, 10Mbps, 25Mbps, 60Mbps, 100Mbps and 160Mbps


Data Rate Limits

DVB-S2X: 100kbps to 160Mbps

DVB-S2: 350kbps to 132Mbps FastLink™ LDPC: 18kbps to 100Mbps TPC: 4.8kbps to 60Mbps

1bps resolution


Symbol Rate Limits

DVB-S2X: 100ksps to 50Msps

DVB-S2: 350ksps to 37.5Msps FastLink™ LDPC: 18ksps to 40Msps TPC: 9ksps to 40Msps


Operating Modes

DVB-S2X (EN 302 307-2) option

DVB-S2 (EN 302 307-1) option

Closed Network (+ ESC) (IESS-315)

IBS/IDR (IESS-308/309/310/314) options



DVB-S2/DVB-S2X: As per EN 302 307

IBS: As per IESS-309

Closed Network + ESC: Synchronised to ESC overhead


IF: 50Ω/75Ω

L-band: 50Ω

Return Loss

IF: >18dB

L-band: >15dB


1:1 or up to 1:16 redundancy