science

LowFER

LowFER is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand LowFER rather than just read about it. In short: LowFER (Low-Frequency Experimental Radio) refers to experimental radio communication practiced by hobbyists on frequencies below 300 kHz, a part of the radio spectrum known as low frequency. The practitioners are known as "LowFERs".

Key takeaways

LowFER belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect LowFER to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of LowFER from memory before moving on to harder problems.

Reference excerpt

LowFER (Low-Frequency Experimental Radio) refers to experimental radio communication practiced by hobbyists on frequencies below 300 kHz, a part of the radio spectrum known as low frequency. The practitioners are known as "LowFERs".

Practices LowFER operation is practiced in the United States and Canada on radio frequencies between 160 kHz and 190 kHz which is sometimes referred to as the 1750-meter band, and in the past as the 1875-meter band. In much of the world, including the U.S., there is an adjacent amateur radio band at 136–138 kHz with a number of U.S. amateur radio operators authorized to transmit on that band (notification and lack of objection from power utilities is required). Radio operators who conduct low-frequency experimental operations on the LowFER band are known as LowFERs (pronounced "loafers"). Many LowFERs are also licensed radio amateurs, although an amateur radio license is not required for LowFER communications in those countries in Region 2, as long as the power is below a nationally prescribed limit, often 1 W.

Equipment Practical antennas at these frequencies are much shorter than the wavelength, making it difficult to efficiently radiate much useful power. By current U.S. and Canadian regulations, LowFER transmitters may not have antenna and feed line lengths longer than 15 metres (49 ft), or final RF stage input powers that exceed 1 watt. Telegraphy and digital modes are the most commonly used for communications, but speech transmission via amplitude modulation (AM) or single-sideband modulation (SSB) is also allowed. Even with such short antennas and low transmit power, LowFER stations have been heard at distances approaching 1,000 miles by listeners using sophisticated receiving setups.

Similar activities

LF amateur radio allocation

In Europe, and generally in ITU Region 1, the LowFER frequency range (160–190 kHz) is used for broadcasting and is unavailable for two-way communications use. In the United Kingdom there was an allocation for radio amateurs at 73 kHz between 1998 and 2002. The International Telecommunication Union's 2007 World Radiocommunication Conference (WRC-07) in Geneva agreed a secondary allocation 135.7–137.8 kHz (the 2200-meter band) to the Amateur Service on 9 November 2007, marking the first time since amateur allocations began that there has been an amateur band below the medium wave broadcast band. Transmitter power is limited to one watt ERP (meaning an inefficient antenna can be fed a higher power).

MedFER In the U.S., license-free operation is also allowed on the medium frequency band, also known as the AM broadcast band. Similar to LowFER, MedFER is medium-frequency experimental radio. MedFER enthusiasts operate under FCC Part 15 rules using 0.1 W (a tenth of a watt) and a three-meter-long antenna between 510 kHz and 1705 kHz, coinciding with the U.S. AM radio band.

HiFER HiFER is high-frequency experimental radio operating within a 14 kHz-wide band centered at 13.56 MHz. This frequency range is allocated to industrial, scientific and medical uses as well as low-power communication devices under FCC Part 15 rules, where a small level of radio frequency radiation is allowed without licensing. (See RFID for other uses of this frequency.)

Worked examples

Example 1 — a first encounter with LowFER

Start with the simplest possible case. Write down what LowFER claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to LowFER before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about LowFER ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of LowFER

In research: LowFER appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses LowFER in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: LowFER is common in secondary-school and first-year university syllabi. It links to neighbouring topics Amateur radio, Radio hobbies, so understanding it makes those chapters shorter.
In everyday life: Look for LowFER outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study LowFER in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LowFER means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain LowFER out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LowFER in simple terms?

Why does LowFER matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study LowFER?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on LowFER.