Note
QST, Jun 1974, p.140.
QST, Jan 1975, p. 148.
QST, Apr 1976, p. 102.
Ham Radio, Jun 1977, p. 96.
QST, Nov 1977, p. 110.
The SABA-5 pre-amplifier used a MOSFET device and had band-switched coverage of 80–10 meters. It provided more than 20 dB gain with a noise figure less than 2.5 dB.
The SABA-5 (Symtek Automatic Broadband Amplifier) provides low-noise and high useful gain for amateur communications receivers. This new amplifier, which covers 80, 40, 20, 15 and 10 meters with no tuning has a typical noise figure of 2.5 dB and gain of 20 dB (minimum). Input and output impedance is 50 ohms.
The SABA-5 uses a dual-gate, diode- protected MOSFET to take advantage of its low noise characteristics as well as its inherent protection against strong RF fields. The Qs of the tuned circuits are engineered for high gain and adequate bandwidth to cover the entire amateur bands with MARS overlap. Insertion loss, when the amplifier is turned off, is kept to a minimum through the use of a straight-through coaxial loop and low-loss ceramic switches.
Biasing of the amplifier is optimized for best gain, cross-modulation and
noise-figure characteristics. Gain may be adjusted by varying the main supply voltage +3 volts. The amplifier is easily installed on any communications receiver by simply inserting it between the receiver and the antenna. Transceivers may be easily modified by breaking the antenna circuit from the T/R relay to the receive RF amplifier and bringing each end to an external phono jack.
Available in several configurations:
1R – Battery operation, receive only
2R – 120 VAC, receive only
1T – Requires 12–18 VDC @ 100 mA, has T/R switch
2T – Externally gated operation for 120 VAC, has T/R switch
3T – Automatically gated operation for 120 VAC, has T/R switch
2MM – 2 Meters, mobile DC operation, has T/R switch
2MB – 2 Meters, base unit, has T/R switch