CLOVER2000
Higher-rate HF waveform developed in 1995.
CLOVER-2000 is a higher-rate and wider bandwidth version of the CLOVER series of modem modulation techniques designed for use over high frequency (HF) radio systems. It was developed in 1995 as an evolution of the earlier CLOVER-II waveform.
- Developed
- 1995
- Type
- higher-rate and wider bandwidth version of CLOVER
- Modulation schemes
- BPSK, QPSK, 8PSK, 8P2A, 16P4A
- Data block size
- 255-byte blocks
- Fec broadcast mode
- usually disabled
Lore & Background
CLOVER-2000 was developed in 1995 as a higher-rate and wider bandwidth version of the CLOVER waveform, which was originally created by Ray Petit, W7GHM, and HAL Communications in 1990–92. The CLOVER series is specifically designed for use over HF radio communications links. In ARQ mode, all CLOVER Control Blocks (CCBs) use BPSK modulation, while data blocks may be sent using BPSK, QPSK, 8PSK, 8P2A, or 16P4A modulation. Data is transmitted in 255-byte blocks. The FEC broadcast mode of CLOVER-2000 is usually disabled, although special formats are available for specific applications.
Reader's Guide
CLOVER-2000 represents a significant advancement in HF data communications, offering higher data rates and wider bandwidth compared to its predecessor. Its use of multiple modulation schemes—including BPSK, QPSK, 8PSK, 8P2A, and 16P4A—allows flexible trade-offs between speed and robustness. The waveform is designed to work with virtually any modern HF SSB radio, though special setup and adjustment techniques are required for maximum performance. The FEC broadcast mode is typically disabled, indicating that the primary application is ARQ-based error-free communication. CLOVER-2000's spectral efficiency and error correction capabilities make it notable among HF waveforms, though its adoption has been shaped by the specific needs of HF radio operators and commercial users such as Globe Wireless, for whom a special 400 Hz wide variant (CLOVER-400) was developed.
Did You Know?
- Data blocks in CLOVER-2000 can use BPSK, QPSK, 8PSK, 8P2A, or 16P4A modulation.
- CLOVER-400 is a special 400 Hz wide waveform developed for Globe Wireless.
Frequently Asked Questions
What is CLOVER-2000?
CLOVER-2000 is a higher-rate, wider-bandwidth HF modem waveform that was created as an evolution of the earlier CLOVER-II design. It sits within the broader CLOVER family of modulation techniques built for high-frequency radio links.
When was CLOVER-2000 developed and what prompted it?
It was developed in 1995 as a next-step refinement of the CLOVER-II waveform, aimed at pushing throughput and bandwidth further on HF channels.
Which modulation schemes can CLOVER-2000 use?
The waveform supports BPSK, QPSK, 8PSK, 8P2A, and 16P4A, giving operators a range of spectral-efficiency options depending on channel conditions.
How is data organized in CLOVER-2000 transmissions?
Payload is carried in 255-byte blocks, a fixed framing size that the modem uses for encoding and error-control processing.
Is the FEC broadcast mode typically active in CLOVER-2000?
No—FEC broadcast mode is usually left disabled in standard CLOVER-2000 operation, meaning the forward-error-correction broadcast channel is not routinely transmitted.
More in Radio Modulation Modes, Part 2 1-24
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