Operating Activities: Hunting, Contesting, and Linking

Radio direction finding

Which of the following methods is used to locate sources of noise interference or jamming?

Radio direction finding.

Which of these items would be useful for a hidden transmitter hunt?

A directional antenna.

The method is the same whether the target is a deliberately hidden transmitter in a park or a failing power-line insulator interfering with your receiver: take bearings from several places and triangulate.

A directional antenna is the essential tool because it tells you where, not just how strong. In practice you also want an attenuator — close to the source everything reads full scale, and without attenuation the bearing disappears exactly when you need it most.

This is the most useful amateur skill for a real problem: when something is interfering with you, direction finding is how you find it rather than guess.

Contesting

What operating activity involves contacting as many stations as possible during a specified period?

Contesting.

Which of the following is good practice when contacting another station in a contest?

Sending only the minimum information needed for proper identification and the contest exchange.

Contest style is terse to the point of curtness, and that is correct rather than rude: with a thousand stations calling, every extra word costs someone else a contact. Call sign, exchange, acknowledgement, next.

Grid locator — a letter-number designator assigned to a geographic location — is the exchange in most VHF and UHF contests. Maidenhead grid squares like EN82 cover about 1° by 2°, and a six-character version narrows it further. It is also the position format FT8 uses.

Internet linking

Three systems that connect radio to the internet, and the pool distinguishes them.

VoIP — a method of delivering voice communications over the internet using digital techniques. The underlying technology, not an amateur system.

IRLP — the Internet Radio Linking Project — a technique to connect amateur radio systems, such as repeaters, via the internet using VoIP. Access is by using DTMF signals: you key in a node number from your radio and the repeater connects to a distant one.

Note what IRLP is not: it is radio at both ends. Every participant is on the air through a repeater somewhere.

EchoLink — enables an amateur station to transmit through a repeater without using a radio. It permits connection from a computer or phone, which is the significant difference from IRLP.

Because a non-radio connection needs verifying, EchoLink requires that you register your call sign and provide proof of licence before use. The system enforces what the rules require: only licensed amateurs on amateur frequencies.

Gateway — an amateur radio station that connects other amateur stations to the internet. The generic term for the station at the boundary.

Check yourself

1. A neighbour’s device is interfering with 2 metres. What technique finds it, and what equipment do you need?
2. What is the difference between IRLP and EchoLink?
3. Why must you register before using EchoLink?