Spooltenna ULTRA-4010 End Fed Half Wave Portable Wire Antennas are a 40-10M end fed half wave antenna in an ultra-compact form that is small enough to fit right into your pocket. Optimized for size and weight without compromising performance, it is ideal for POTA, SOTA, backpacking, and travel.

Antenna tuner not required.

Theory of Operation

The end fed half wave antenna has become a popular option for portable station operating due to its simplicity and ease of deployment. Feeding the antenna from one end reduces the number of support structures required to elevate the radiating element compared to a traditional dipole. This antenna design has a higher impedance at the feed point of approximately 2500 ohms compared to 50 ohms for a dipole antenna, which necessitates the use of an impedance matching circuit. In this case feeding the antenna using unbalanced coax cable to an unbalanced (single ended) radiating element calls for an UNUN impedance matching circuit. This circuit consists of a 49:1 impedance ratio transformer achieved through a 7:1 turns ratio. A 100pF, 3kV capacitor is also included across the feed point of the antenna to further impedance match to the radio.

What's In The Box

Includes:

• SPOOLTENNA ULTRA-EFHW4010

• Field Testing Report for that serial number

• Quick Start Guide with link to Owners' Manual

Features:

• Center hole - 8mm (approximately 5/16in.) for quick deployment using a standard screwdriver as an axle (screwdriver not provided)

• Low-profile winding knob for easy set up and tear down

• Thermal venting on back for high-duty cycle operation

• 4mm banana jack for quick connection/disconnection of radiating element

• 8mm mounting holes on face and back side of the product for mounting or hanging flexibility

• Right-angle BNC connector to align with feedline direction

• Matching circuit captive within the barrel of the spool to protect circuit components

• Strain relief loop on both ends of the radiating element

• Supplied with BongoTies® tie for retaining wire on the spool

• Designed for use with lightweight coax such as DX Engineering RG-8X Hi-Viz coax feedline (sold separately)

Specifications:

Frequency Range:

• 7.0 - 7.3 MHz (40M)

• 14.1 - 14.35 MHz (20M)

• 21.0 – 21.45 MHz (15M)

• 28.0 – 29.7 MHz (10M)

Power: 100W SSB, 50W CW & Digital

Dimensions:

• Diameter: 3.0in. (76mm)

• Thickness: ~0.98in. (25mm) (minus the BNC connector and knob protrusions)

Weight: 5.7oz.

Length: 65ft. of insulated 26AWG high strength, high conductivity Copper Clad Steel (BCCS), UV resistant polyethylene jacket

Note: Antenna is factory-tuned, with additional length available for end-user final tuning.

RF Connection: Right-angle BNC female