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Station S21AMF

ITU Region 3 · Zone 41

The academy is directed by Dr. Sheikh Md. Mahtabur Rahman, licensed radio amateur and telecommunications specialist.

Official Email: mahtab@s21amf.com

Station QTH: Dhaka, Bangladesh

Grid Locator: NL53er

HF Monitor: 14.200 MHz · 7.100 MHz

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Amateur Radio Glossary

ITU, RF & Technical Definitions

SWR / VSWR Voltage Standing Wave Ratio

A measure of impedance matching between the transmission line and the antenna. An SWR of 1.0:1 is a perfect match.

CW Continuous Wave

The transmission of International Morse Code by keying an unmodulated RF carrier wave.

QRP Low Power Radio Operation

Operating with 5 Watts RF output or less on CW, and 10 Watts PEP or less on SSB.

SSB Single Sideband

An efficient form of amplitude modulation where the carrier and one of the sidebands are filtered out.

DX Distance Transmission

Amateur radio communication over long distances, typically between different continents or rare countries.

Balun Balanced to Unbalanced

An impedance or isolation transformer connecting a balanced antenna (like a dipole) to unbalanced coax.

Yagi-Uda Directional Beam Antenna

A multi-element directional antenna using a driven element, a reflector, and one or more directors for high forward gain.

Dipole Half-Wave Wire Antenna

The fundamental resonant antenna measuring approximately 468/f(MHz) in feet, fed at the center.

Maidenhead QTH Grid Locator

A worldwide coordinate locator system encoding latitude and longitude into 4 or 6 alphanumeric characters.

UTC / Zulu Coordinated Universal Time

The international astronomical time standard used for all amateur radio logs to avoid time zone ambiguity.

Attenuation Signal Loss in Transmission

The reduction in signal strength that occurs as radio frequency power passes through coax or filters.

BTRC Bangladesh Telecom Regulatory Commission

The statutory regulatory authority responsible for administering Amateur Radio licensing exams and callsigns.

ITU International Telecommunication Union

United Nations specialized agency that coordinates the global shared use of the radio spectrum.

Dr. Mahtabur Rahman S21AMF · Cadet Glossary