Comet Antenna HFJ-350M User Manual

Instruction Manual
MODEL
【 Features 】
● It is a 3-division structure that is convenient to carry.
● Telescopic antenna for multi-band HF to 50 MHz band, whose frequency can be easily changed by short plug.
● Round-shape solderless Terminal for counterpoise is included. (Stranded wire: 3.5 sq [AWG12] compatible)
【Product image】
accessories
Short plug
Cautions on installation
◆ This product is not suitable for mobile use. Please do not set it on the vehicle and drive.
◆ If there are other antennas or obstacles such as buildings near this antenna, this will cause
SWR degradation and resonance frequency shift. In that case, please change the mounting
position of the antenna.
!
◆ Make sure that the connector of the connection cable and the antenna connector are of the
same type. If it is a different type, it can not be connected or it may be damaged.
HF-50MHz Portable Telescopic Antenna
For : 3.5 / 7 / 10 / 14 / 18 / 21 / 24 / 28 / 50 MHz
Handling and operation precautions
!
Base Coil
with connector
Product configuration
3.5 MHz expansion coil
connection & Telescopic
element shortest
HFJ-350M
M-P (PL-259)
Connector
3.5MHz
Expansion coil
Telescopic
Element
Thank you for purchasing our products.
For your safety :
Read this manual carefully for proper handling and operation before using.
Keep this manual in a safe place for future reference.
【 Specifications 】
Antenna type : 1/4 λ base loading type antenna
Frequency : 3.5 / 7 / 10 / 14 / 18/ 21 / 24 / 28 / 50 MHz 9-Bands
Max.Input Power : 75W (SSB) [3.5MHz] , 100W (SSB) [7 - 50MHz]
Impedance : 50Ω
Length : Min. 370mm , Max. 1665mm
Weight : approx. 260g (included 3.5MHz expansion coil)
Antenna Connector : M-P (PL-259)
● When installing or removing the antenna or adjusting the element, be careful not to open your
eyes at the end of the rod.
● Do not touch the antenna during and immediately after transmission. The fever can cause burns.
● Tighten the fixing screws firmly so that there are no accidents.
● When extending the rod, always keep in mind that there are no obstacles in the height direction.
● Do not use it outdoors when it is wet, as it is not waterproof.
● Do not use when the surface is wet, and use completely dry.
◆ To use this product, capacitive coupling with grounding or counterpoise is required.
Note that if the ground capacitance is insufficient, the VSWR characteristics will deteriorate,
especially in the low frequency band, and there is a high possibility that adjustment will not be
possible.
◆ On the structure shortened by the loading coil, the tuning band is narrow. If you want to check
where the tuning frequency is, we recommend using an antenna analyzer such as CAA-500Mark II.

Comet Antenna HFJ-350M Specifications

General

Brand	Comet Antenna
Model	HFJ-350M
Category	Antenna
Language	English

Summary

Safety Precautions

Manual Handling and Reference

Read this manual carefully for proper handling and operation before use and keep it for future reference.

Product Features and Specifications

Key Features

Features include a 3-division structure for portability, multi-band HF to 50 MHz capability, and a solderless terminal.

Technical Specifications

Details include 1/4 wave base loading, frequency range, max input power, impedance, length, weight, and connector type.

Installation and Handling Guidelines

Installation Cautions

Requires capacitive coupling, tune band may narrow, check connector compatibility, not for mobile use, avoid obstacles.

Operation Precautions

Handle elements carefully, avoid touching antenna during transmission, secure screws, be aware of extension obstructions, and avoid wet conditions.

Connection and Adjustment Procedures

3.5 MHz Band Connection

Connect the 3.5 MHz expansion coil and adjust telescopic element length without a short plug.

7 to 50 MHz Band Connection

Connect telescopic element directly to base coil. Use short plug for 7 MHz band and higher frequencies.

Frequency Tuning Adjustments

Adjust telescopic element length for tuning frequency. Lower frequency by stretching, increase by shrinking.

Counterpoise Connection

Connect a counterpoise wire (e.g., polyvinyl chloride insulated wire) to the R-shaped terminal for better communication.

Performance and Troubleshooting

SWR Check and Tuning

Check SWR by adjusting telescopic length, counterpoise length, and wire arrangement. Use an antenna tuner if needed.

Environmental Factors

SWR may vary based on grounding and installation position. Antenna tuner is recommended for low frequency bands.

Operational Considerations

Product is for amateur radio only. Stop use if abnormal phenomena occur. Check connector fit and avoid continuous output.