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Frequency Hopping System

HAVE QUICK is the codename of an American Frequency Hopping system. It is used for the protection of military UHF radio traffic, such as air-to-air and ground-to-air communications in the 225-400 MHz band. It was introduced in 1980 as an Electronic Counter Counter-Measure (ECCM) after it became clear in the 1970s that aircraft communication could easily be intercepted and jammed by a third party with inexpensive means.

As most of the radios used in aircraft communication were already synthesizer-based, it was relatively easy to add frequency hopping to it. As of 2007, nearly all US military aircraft use HAVE QUICK frequency hopping. HAVE QUICK was later improved to HAVE QUICK II and is now in use by both the US and the UK. HAVE QUICK II is also used by the Second generation Anti-jamming Tactical UHF Radio for Nato (SATURN).

Please note that HAVE QUICK is not an integrated radio system like SINCGARS and that the method used for frequency hopping is not compatible with SINCGARS frequency hopping either. The SINCGARS radios work on a different radio band and use a different frequency hopping method. There are, however, radios that have both methods implemented.

The new Joint Tactical Radio System or JTRS (pronounced jitters) is based on Software Defined Radio (SDR) and supports both SINCGARS and HAVE QUICK frequency hopping.

HAVE QUICK radios use a very complex frequency hopping scheme that is extermely difficult to predict. It is linked to the actual time of day (TOD) and requires a very accurate clock. Usually, a GPS receiver is used for this. At the heart of the system is a microprocessor-based cryptogpaphic pseudo-random number generator that is initiated with:

  • TOD - Time of Day
  • WOD - Word of Day
  • NET - Net number
The WOD is used as a key and the NET number allows multiple nets to use the same WOD. Together, TOD, WOD and NET are used as input (seed) to the pseudo-random number generator that controls the frequency changes. Please note that HAVE QUICK itself is not an encryption system, but an ECCM (electronic counter counter-measure). It can, however, be used in combination with encryption systems, such as the KY-57 (Vinson), the KY-58 (Vinson), the KY-99 (MINTERM) or the KY-100 (AIRTERM).

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Crypto Museum. Created: Wednesday 31 March 2010. Last changed: Sunday, 25 February 2018 - 18:03 CET.
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