Sunair F-9810B Pre/Postselector

The Sunair F-9810B Pre-selector/Post-selector permits operating collocated Sunair 8400 Series radios, whether transceivers, transmitters, or receivers, on frequencies
with as small as a 10% separation.

The Sunair F-9810B HF Pre-selector/Post-selector is a professional , high performance HF multicoupler.

The Sunair F-9810B HF Pre-selector/Post-selector is controlled by the 8400 Series radio it serves.
When used with the various models of the Sunair R-8400 HF Receiver, Wideband, Sunair RT-8500WB HF Transceiver, Wideband, T-10000 HP 10kW HF Transmitter, Wideband, Sunair 8220WB 1 kW HF Transmitter, Wideband, Sunair 8220WB 1 kW Transceiver, Wideband, Sunair 5 kW HF Transmitter, Wideband.

The Sunair F-9810B HF Pre-selector/Post-selector functions as a pre-selector and provides an additional front end selectivity stage, thus reducing the receiver desensitization and overload that normally occurs in the presence of strong adjacent RF transmissions.
When used with the T-8400 Software-Defined HF/ISB Transmitter, the Sunair F-9810B Pre-selector/Post-selector functions as a post-selector, rejecting spurious outputs and broadband noise in the transmit signal before it reaches the Sunair LPA power amplifiers, thereby limiting interference to collocated receivers.
A separate transmit antenna port provides the flexibility of using either a single antenna or separate transmit and receive antennas.

In addition, the keyline over coax feature prevents damage to the unit from high power RF transmission by reducing the control time delay of transmitto-receive switching.
The Sunair F-9810B HF Pre-selector/Post-selector offers a selectivity of 35 dB minimum (±10%), 40 dB typical, from the nominal tune frequency, with an ultimate rejection of 70 dB minimum.

The unit tunes in 10 Hz increments, and tuning time is 10 ms maximum, making the Sunair F-9810B Pre-selector/Post-selector suitable for ALE applications. Furthermore, the Sunair F-9810B Pre-selector/Post-selector offers two levels of gain.
The Sunair F-9810B Pre-selector/Post-selector’s intuitive modular design allows for ease of maintenance and upgrade throughout the equipment life cycle at minimal expense.

• Improves Cosite Performance
• Attenuation 40 dB Typical / 70 dB Maximum
• Selectable Gain
• Individual Transmit and Receive Antenna Ports
• Automatic Tracking 10 ms Tuning
• Automatic RF Overload Protection
• Automatic Bypass

• MIL-STD 810F, Method 516.5, Procedure 1
• MIL-STD 810F, Method 514.5 & MIL-STD-167-1

HF pre/postselector

HF pre/postselectors are specialized filtering units used in high-frequency (1.5–30 MHz) communication systems to improve signal quality and prevent interference, particularly in environments where multiple radios are operating in close proximity (cosite locations).

• Preselector (Receive Mode): Functions as a highly selective band-pass filter between the antenna and receiver. It blocks strong out-of-band signals that would otherwise cause receiver desensitization, cross-modulation, or intermodulation distortion.
• Postselector (Transmit Mode): Acts as a filter between the transmitter and antenna to suppress spurious emissions, harmonics, and broadband noise. This prevents the transmitter from interfering with nearby receivers on adjacent frequencies.