2m · 70cm
Bands
5 dBi
Gain
2010
Introduced
Frequency144-148 MHz, 430-450 MHz
Typemobile whip
Gain5 dBi (5.0 dBi on 2m, 7.6 dBi on 70cm)
Polarizationvertical
ModesFM, SSB, CW, digital
Length157 cm
Weight400 g (14.1 oz)
ConnectorUHF (PL-259 base) — direct mobile mount
MountUHF mobile mount (lip mount, hole mount, or body mount — NOT magnetic mount)
Year2010
Connectors
feedpointUHF (PL-259) base mount. NOT recommended for magnetic mount.
highest-gain Diamond dual-band mobile 62 inches (157cm) 5.0 dBi VHF (2×1/4 wave + 1×3/8 wave) 7.6 dBi UHF (3×5/8 wave) 150W (not 200) fold-over hinge 24Kt gold plated connector pin factory pre-tuned NOT for magnetic mount
Strengths

Diamond's highest-gain dual-band mobile antenna: 5.0 dBi on VHF and 7.6 dBi on UHF from 62 inches, using a C-Load structure. It is factory pre-tuned with wideband performance, with a gold-plated connector pin and a fold-over hinge for garages. It noticeably outperforms shorter dual-band antennas for reaching distant repeaters, with Diamond Supergainer build quality.

Weaknesses

62 inches is tall (the fold-over hinge is essential). It is not recommended for a magnetic mount (too tall and heavy) and needs a proper UHF mobile mount (lip, hole, or body). 150W. It is conspicuous.

Verdict

Diamond's highest-gain dual-band mobile. When range matters more than stealth, the SG-7900A offers the most gain in Diamond's mobile line. The height is the point, and the fold-over handles the garage.

The Diamond SG7900A is a high-gain dual-band mobile antenna — a long, flexible whip for 2 meters and 70 centimeters designed to get the most reach from a vehicle. At 62 inches it is among the taller mobile antennas, and that length buys real gain: about 5.0 dBi on 2 meters and 7.6 dBi on 70 centimeters, noticeably better than a short stubby mobile whip.

It is a radialless design that uses the vehicle body as its ground plane, includes a fold-over joint so it can be laid down for garages and car washes, and handles up to 150 watts. The standard version uses a PL-259/UHF mount; an NMO variant is also made. Its height is the main caveat — it is tall enough to catch on low obstructions, which is exactly why the fold-over feature exists.

It is a current product and a popular high-performance mobile stick. For a base-station antenna in the same band pairing, the Diamond X50A is the entry base vertical, and for a handheld the Diamond SRH77CA is the matching HT whip.