ICAS vs. CCS in BALUN or LINE ISOLATOR power specifications

ICAS = Intermittent Commercial and Amateur Service

as compared to

CCS (Continuous Commercial Service).

These two service types were first defined in the power-tube industry. The classical definitions are as follows:

Continuous Commercial Service (CCS) is defined as that type of service in which long life and reliability of performance under continuous operating conditions are the prime considerations.

Intermittent Commercial and Amateur Service (ICAS) is defined to include the many applications where the transmitter design factors of minimum size, light weight and considerably increased power output are more important than long tube life. In this service, life expectancy may be one-half that obtained in Continuous Commercial Service.

Under the ICAS classification are such applications as amateur transmitters, and the use of devices in equipment where transmissions are of intermittent nature. Intermittent operation implies that no operating or ‘on’ period exceeds 3 minutes, and every ‘on’ period is followed by an ‘off’ or standby period of at least the same or longer duration.

As applied to passive amateur radio products like BALUNs, LINE ISOLATORS, FILTERS, POWER ATTENUATORS, COAXIAL CABLES and ANTENNAS, ICAS does not imply reduced device life, as these devices are not regarded as consumables. Rather, ICAS in such an environment implies de-rating to keep the product’s  temperatures within its maximum ratings. Thus, ICAS suggests a limited operating or ‘on’ period followed by an ‘off’ or standby period of at least the same or longer duration, whilst CCS assumes extended periods of continous operation, at reduced output . As such, appropriate de-rating not only concerns VSWR, but also modulation type, TX/RX duty cycle and environmental conditions.

For amateur radio use, the following recommendations apply:

Apply ICAS values for general SSB and low duty cycle CW use.

Apply CCS values for contest style SSB, high duty cycle CW, RTTY and FT8 use.

Remark: ON7FU products are labelled with worst case (CCS) values.

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