Intermediate Sample Questions

Three questions from each section of the Intermediate syllabus. Pick an answer to see whether you're right, how everyone else did, and why.

Intermediate exam guide

1 Licensing conditions and station identification

On which of these frequency bands must an Intermediate licensee accept interference from ISM users?

  1. 2400 to 2450 MHz
  2. 144 to 146 MHz
  3. 7000 to 7100 kHz
  4. 28.0 to 29.7 MHz

Answer: A, 2400 to 2450 MHz. Per Schedule 1 (EX308, Jan 2026), 2400–2450 MHz is Secondary with an explicit note that users must accept interference from ISM users. Both amateur and amateur satellite entries carry this ISM condition.

When operating a station by remote control, what must be displayed on or next to unattended Radio Equipment located away from the licence address?

  1. The RSGB membership number
  2. The radio's serial number
  3. The operator's name and address
  4. The Licence Number

Answer: D, The Licence Number. Syllabus 1E1 requires the Licence Number to be displayed on or next to unattended Radio Equipment located other than at the address shown in the licence. Name, serial number, or RSGB membership number do not satisfy this condition.

An Intermediate licensee wants to operate amateur radio from a UK-registered aircraft in international airspace. What restriction applies?

  1. They may only use 2m FM
  2. They must use primary allocations only and limited power
  3. Operation is not permitted from aircraft at any time
  4. They need a Full licence to operate from aircraft

Answer: B, They must use primary allocations only and limited power. Syllabus 1A2 (Intermediate) states airborne operation is restricted to primary allocations only, with a maximum of 500 mW EIRP airborne, per Intermediate Licence Schedule 1 (EX308 Jan 2026).

2 Technical aspects

If the Peak-to-Peak voltage is 20V, what is the Peak voltage?

  1. 20 V
  2. 7.07 V
  3. 10 V
  4. 14.14 V

Answer: C, 10 V. Peak-to-peak voltage is measured from the negative peak to the positive peak, so it is twice the peak value. A 20 V peak-to-peak waveform therefore has a peak voltage of 10 V (Intermediate syllabus 2E3).

At resonance, a series tuned circuit presents:

  1. Infinite impedance
  2. Very high impedance
  3. An impedance equal to the supply voltage
  4. Very low impedance

Answer: D, Very low impedance. At resonance XL = XC; they cancel, leaving only the series resistance. A series tuned circuit therefore presents very low (near-zero) impedance at its resonant frequency, per syllabus 2H2.

Two capacitors of 100 pF each are connected in series. What is the total capacitance?

  1. 200 pF
  2. 25 pF
  3. 50 pF
  4. 100 pF

Answer: C, 50 pF. Series capacitance: 1/C_total = 1/C1+1/C2. For two equal 100 pF: C_total = 100/2 = 50 pF (per syllabus 2D2). Series always yields less than the smallest individual value.

3 Transmitters and receivers

An oscillator produces a signal at 7.1 MHz. If this signal passes through a non-linear stage, which of the following frequencies could appear as an unwanted harmonic?

  1. 10.65 MHz
  2. 14.2 MHz
  3. 21.0 MHz
  4. 3.55 MHz

Answer: B, 14.2 MHz. Intermediate syllabus 3G2: harmonics are whole-number multiples of the fundamental. Twice 7.1 MHz is 14.2 MHz, the second harmonic, which could be radiated into another amateur band unless filtered.

An RF power amplifier stage has a DC input power of 100 W and an efficiency of 60%. What is the RF output power?

  1. 40 W
  2. 100 W
  3. 60 W
  4. 160 W

Answer: C, 60 W. Efficiency is the fraction of DC input power that comes out as RF. So 60% of 100 W gives 60 W of RF output, and the other 40 W is lost as heat in the stage (Intermediate syllabus 3F1).

Interference to a radio receiver from a nearby transmitter on a different frequency is often caused by:

  1. The transmitter drifting
  2. Receiver Front-end Overload / Blocking
  3. Atmospheric conditions
  4. The receiver being too sensitive

Answer: B, Receiver Front-end Overload / Blocking. A very strong nearby signal can overload the receiver's front end, even when it is on a different frequency. This causes blocking and distortion. See Intermediate syllabus 3H3 on receiver overload.

4 Feeders and antennas

A 100 W transmitter is connected to an antenna via 20 metres of coaxial cable that has a loss of 1.5 dB per 10 metres at 28 MHz. Ignoring any mismatch effects, approximately what power is delivered to the antenna?

  1. 50 Watts
  2. 100 Watts
  3. 75 Watts
  4. 25 Watts

Answer: A, 50 Watts. 20 m of cable at 1.5 dB/10 m gives 3 dB total loss. 3 dB loss halves the power (per syllabus 9B1 dB rules): 100 W ÷ 2 = 50 W delivered to the antenna. No mismatch effects applied as stated.

If you raise an HF dipole from 0.25 wavelengths to 0.75 wavelengths above ground, how does the radiation pattern primarily change for DX work?

  1. The low angle radiation lobes increase
  2. The take-off angle increases significantly
  3. The high angle lobes disappear completely
  4. The azimuth pattern becomes omnidirectional

Answer: A, The low angle radiation lobes increase. Raising an HF dipole higher above ground lowers its main angle of radiation, so the low-angle lobes get stronger. That is exactly what long-distance (DX) work needs. Intermediate syllabus 4C5 covers how the ground affects the angle of radiation and why longer distances need a lower angle.

If an Antenna Matching Unit (AMU) is located at the transmitter, what effect does it have on the SWR between the AMU and the antenna?

  1. It has no effect on the SWR between the AMU and antenna
  2. It eliminates all standing waves everywhere
  3. It doubles the SWR
  4. It reduces the SWR on the feeder between AMU and antenna

Answer: A, It has no effect on the SWR between the AMU and antenna. Per syllabus 4F1, an AMU at the transmitter matches the transmitter output to the feeder input impedance only. The mismatch at the antenna end is unchanged, so SWR on the feeder between AMU and antenna is unaffected.

5 Propagation

The polarisation of an electromagnetic wave is defined by the orientation of its:

  1. Electric field
  2. Direction of travel
  3. Magnetic field
  4. Frequency

Answer: A, Electric field. Polarisation is defined by the plane of the electric (E) field vector. A vertical antenna produces a vertically polarised wave with E vertical to the ground (syllabus 5A3).

The D layer tends to absorb lower frequency HF signals during the day. At night, it:

  1. Largely disappears
  2. Increases in density
  3. Reflects VHF signals
  4. Moves higher in the atmosphere

Answer: A, Largely disappears. Per syllabus 5B4, the D layer is sustained by solar UV. At night, ionisation rapidly recombines and the layer largely disappears, removing daytime absorption of lower HF frequencies.

At VHF and above, multipath propagation occurs when signals are:

  1. Refracted from the F2 layer and received in place of the direct signal
  2. Attenuated by rain or snow and received via the direct path only
  3. Reflected off buildings or aircraft and received with the direct signal
  4. Bent over a hill by diffraction and received instead of the direct signal

Answer: C, Reflected off buildings or aircraft and received with the direct signal. Multipath at VHF and above happens when signals reflect off objects such as buildings or aircraft and arrive in addition to the direct signal (Intermediate syllabus 5C3). The two can interfere with each other.

6 Electromagnetic compatibility

Solar photovoltaic (PV) inverters can cause interference to amateur radio because:

  1. Their 50 Hz mains output falls inside the HF bands
  2. Their control circuits transmit on amateur band frequencies
  3. Their switching circuits generate wideband RF noise
  4. Their panels absorb RF energy from nearby antennas

Answer: C, Their switching circuits generate wideband RF noise. Solar PV inverters use fast switching circuits that can generate wideband RF noise, heard as buzzing on nearby receivers. Intermediate syllabus 6B2 lists them among non-radio sources of interference.

Which mobile antenna position usually results in the lowest RF field strength inside the vehicle?

  1. On the wing / fender
  2. Centre of the roof
  3. On the glass
  4. On the boot / trunk

Answer: B, Centre of the roof. Centre-roof mounting maximises the metallic ground plane in all directions, symmetrically shielding the vehicle interior and minimising RF field strength inside the cabin (per syllabus 6F3 and FCS Code of Practice).

The purpose of an RF earth connection in an amateur station is to:

  1. Replace the mains safety earth connection
  2. Protect the station from direct lightning strikes
  3. Give RF currents a path to ground, reducing interference
  4. Boost the output power of the transmitter

Answer: C, Give RF currents a path to ground, reducing interference. An RF earth gives RF currents a path to ground, so less RF flows into the mains earth system and causes interference to other equipment. This is covered by Intermediate syllabus 6E2 (Foundation 6E2).

7 Good operating practices and procedures

For amateur satellite operation, the uplink and downlink frequencies are usually:

  1. On the same frequency
  2. On commercial frequencies
  3. Only on 2 metres
  4. In different amateur bands

Answer: D, In different amateur bands. Per syllabus 7G2, amateur satellite uplink and downlink frequencies are in different amateur bands. This prevents the satellite receiver being desensitised by its own transmitter and enables full-duplex operation.

The Q-code "QSY" means:

  1. Please send more slowly
  2. I am increasing power
  3. I am closing down
  4. Change frequency

Answer: D, Change frequency. The Q-code QSY means 'change frequency' (or 'shall I change frequency?'). It is one of the Q codes listed in Intermediate syllabus item 7E1.

Why do band plans include "guard bands" or buffer zones around certain frequencies?

  1. To protect beacons and calling frequencies
  2. To reduce SWR near the edge of each band
  3. To reserve those segments for digital modes
  4. To keep DXpeditions clear of contest stations

Answer: A, To protect beacons and calling frequencies. Band plans keep guard bands around beacon and calling frequencies so ordinary traffic stays clear of them. Transmitting on beacon frequencies should be avoided (7B1), as in the 144.490-144.500MHz beacon guard band.

8 Safety

A gas discharge arrestor fitted in the antenna feeder provides limited protection against:

  1. Receiver overload from strong signals
  2. The build-up of static charge on the antenna
  3. Harmonics from the transmitter
  4. Mains voltage surges

Answer: B, The build-up of static charge on the antenna. Syllabus 8E1 states limited protection against static charge build-up can be obtained from gas discharge arrestors, spark gaps, and bleed resistors. They conduct when static voltage exceeds a threshold but cannot stop a direct lightning strike.

An amateur radio operator is using a 100W transmitter on the 2m band. Compared to using a low-gain antenna, what is the effect on the required EMF compliance distance when a higher-gain antenna is used?

  1. The compliance distance depends only on the transmitter power, not the antenna gain.
  2. The compliance distance decreases because more power is radiated efficiently.
  3. The compliance distance increases because power is focused in a particular direction.
  4. The compliance distance is unchanged because total transmitted power is the same.

Answer: C, The compliance distance increases because power is focused in a particular direction.. Syllabus 8D1 states that at 100W, especially with higher-gain antennas, the EMF compliance distance can be several metres. A higher-gain antenna focuses power in one direction, increasing field strength and therefore the required safe separation distance.

When using a pillar drill, the workpiece should be:

  1. Marked with a centre punch and left unclamped
  2. Held firmly by hand, with fingers clear of the bit
  3. Clamped securely
  4. Rested against the column and drilled slowly

Answer: C, Clamped securely. Intermediate syllabus 8B3: items being drilled must be held securely in a vice or similar device to stop them slipping or rotating. On a pillar drill, that means clamping the workpiece.

9 Measurements and construction

A silver tolerance band on a resistor indicates a tolerance of:

  1. 1%
  2. 5%
  3. 20%
  4. 10%

Answer: D, 10%. The EX308 resistor colour code table lists silver as 10% tolerance. Gold = 5%, no band = 20%, brown = 1%. Per syllabus 9C1, components have tolerances meaning measured values may differ from marked values.

An Intermediate licensee operating on the 20m band measures their transmitter output at 17 dBW. What is the output power in Watts, and is this operation compliant with Intermediate power limits?

  1. 50 Watts, compliant with limits
  2. 100 Watts, exceeds Intermediate limits
  3. 100 Watts, compliant with limits
  4. 50 Watts, exceeds Intermediate limits

Answer: A, 50 Watts, compliant with limits. 17 dBW = 10^(17/10) ≈ 50 W. The Intermediate 20 m limit per Schedule 1 (EX308) is 100 W (20 dBW), so 50 W is well within the permitted level. Conversion: P(W) = 10^(dBW/10).

When measuring voltage, the meter is connected:

  1. In Series
  2. In Parallel
  3. With the circuit switched off and the meter set to ohms
  4. Between the circuit and earth only

Answer: B, In Parallel. A voltmeter measures the potential difference across a component, so it goes in parallel with it. It has a high internal resistance so it draws very little current from the circuit. See Intermediate syllabus 9A2.