The Radio Source 630PD Lowdown 630-Meter Vertical Antennas provide Amateur Radio operators with an efficient and practical solution for operating on the 630-meter band in locations where space is limited. Compact, lightweight, and easy to install, these antennas deliver impressive performance without requiring a large area or tall support structures.

Designed for installation above a horizontal ground radial system, the 630PD utilizes an inductively center-loaded, base-fed configuration with a capacitive top hat to maximize efficiency while maintaining a remarkably small footprint. Its rugged yet lightweight construction makes setup, takedown, transportation, and storage simple.

The antenna is intended for ground-level installation over a horizontal radial field consisting of radials approximately 10 to 25 feet in length. When used with a ground system of 32 radials measuring 25 feet each and operated at typical input power levels of 100 to 200 watts, the antenna can produce an effective radiated power (EIRP) of approximately 2 to 4 watts, depending on local ground conductivity. At its maximum rated input power of 250 watts, EIRP can reach or exceed the FCC's 5-watt limit for the 630-meter band.

The Lowdown 630PD is mounted to a ground support using insulated block clamps that secure the lower antenna section at two points approximately 18 to 24 inches apart. Installation is typically accomplished using a treated 4x4 or 6x6 wooden post set into the ground, leaving 3 to 4 feet exposed above grade. The upper clamp is mounted near the top of the post, with the lower clamp positioned at least 24 inches below to provide secure vertical support.

For easier tuning and maintenance, a tilt-over mounting arrangement may also be used. An optional transmission line impedance transformer can be attached directly to the mounting post, with a short jumper connecting the transformer to the antenna feed point. Ground radial connections can be made conveniently using a copper or aluminum grounding ring installed around the mounting post, providing a simple and cost-effective method for attaching the required radial system.

The result is a highly efficient, mechanically durable, and exceptionally compact antenna system that makes 630-meter operation practical for stations with limited space.

Key Features

• Designed specifically for operation on the 630-meter amateur band

• Compact footprint ideal for small properties and restricted installations

• Inductively center-loaded, base-fed design with capacitive top hat

• Rugged yet lightweight construction

• Easy setup, transport, storage, and maintenance

• Ground-level installation requiring no tall support structures

• Compatible with radial systems using 10 to 25 foot radials

• Supports up to 200 watts input power

• Can achieve FCC-legal 5-watt EIRP when properly installed

• Suitable for both permanent and portable applications

Additional Features & Specifications:

• Type: LF base, vertical, whip, omnidirectional

• Feedpoint Impedance: 20-33 ohms with 25 ft. & 10 ft. radius ground planes, respectively

• Matching: Transmission line transformer may be used to match impedance for best efficiency

• Efficiency: Up to 2.5%

• Power Rating (Approx.): 200-watt carrier

• Frequency Coverage: Tunable 472-479 kHz (630-meter band)

• Operating Height AGL: 24 ft. nominal

• Assembled Length: 21.54 ft.

• Element Diameters: Base: 1.5 in. Coil: 3.75 in., Midtip/Tip: 1.5 in./1.0 in.

• Capacitive Hat: 120 in. diameter (maximum)

• Breakdown: 4 pieces plus 6-element capacitive top hat; longest element 94 in.

• Tuning Adjustments: Capacitive top hat diameter (spoke length)

• Weight: 18.9 lbs.

• Material: Anodized aluminum and fiberglass-reinforced PVC

• Hardware: Stainless steel

• Feed Line Connector: 1/4 in. screw stud

• Recommended Mounting Type: 1.5 in. insulated block mounts

• Mounting Format: Top of mast or pole

• Mounting Structure: 4 × 4 in. wood post (typical)

• Wind Surface Area: 3.15 sq. ft.

• Wind Survivability Rating: 140 mph guyed; 100 mph un-guyed (48 in. mount separation)

• Bandwidth: 3 kHz (3:1 SWR); 2 kHz (2:1 SWR)