A 500 W amplifier, a fortnight in the Netherlands, and a rooftop Yagi
You hold a Greek amateur licence (HAREC-equivalent, call sign SV1ABC) that authorises a maximum transmitter output of 100 W. A friend offers you a 500 W solid-state linear amplifier, CE-marked and covering 144–146 MHz. You have rented a house in the Netherlands for two weeks and plan to enter a 2 m SSB contest running 500 W into a 9 dBi Yagi mounted at 7 m on the roof, with 25 m of RG-213 down to the shack. The roof is not normally accessible to anyone else, but neighbouring houses are 15 m away and their upper windows face your antenna broadside. Contest duty cycle is roughly 40 %.
1. Can you legally run the amplifier? Explain the licence and CEPT constraints that decide it.
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Your licence is the authorisation. It states a maximum transmitter output of 100 W. That figure is a condition of the licence, not a suggestion, and running 500 W puts you outside it whatever the antenna or the country. The amplifier being CE-marked only says it meets EMC and safety requirements as a product; it says nothing about whether you are licensed to use it.
CEPT does not widen your licence. T/R 61-01 lets a visiting amateur operate temporarily in another CEPT country under that country's regulations without a separate national licence. It does not raise your permitted power: you must respect the host country's limit for the band and class, and you cannot exceed the conditions of your own licence either - the more restrictive of the two applies. Before transmitting you must check the Dutch limit for 144 MHz, the band plan and any local restrictions; if it is lower than 100 W, that is your ceiling.
Practical consequences. Operating at 500 W would be an unauthorised transmission, would invalidate any interference or exposure assessment you made, and could not be defended on the grounds that nobody complained. The correct route is either to use the 100 W you are licensed for, or to establish, before you travel, whether your licence can be varied or upgraded - which for a two-week holiday it realistically cannot.
2. Under the CEPT arrangements, what identification, paperwork and pre-departure checks are required before you transmit from the Netherlands?
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Identification. You keep your own call sign but add the host country's prefix in the form the host administration prescribes - for the Netherlands, a call of the PA/SV1ABC type. Check the host's published rule for the exact form, including whether a portable suffix or district indicator is required, and use it every time you identify. Identification must be at the start and end of contacts and at reasonable intervals during long transmissions, and the station must be under your direct control.
Documents. Carry your licence document, together with evidence of the CEPT/HAREC equivalence that T/R 61-01 relies on. Some administrations ask for prior notification even under CEPT, so check the host regulator's website rather than assuming; also confirm that the recommendation covers the licence class you hold and the band you intend to use.
Technical checks before the first transmission. The 144–146 MHz band plan (calling frequency, repeater channels, contest-preferred segments), the host power limit for your class, any restrictions on portable or temporary operation from a rented property, the antenna's planning or landlord constraints, and the RF exposure rules that apply at the site.
Also check your own side. Your Greek licence conditions travel with you; a band or power not permitted at home is not made permissible by going abroad. Log the dates and location of operation, which is useful both for QSLs and for any later query about an interference report.
3. Estimate the RF exposure at the neighbouring windows for 100 W and for 500 W, and give your judgement on the contest plan.
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EIRP. 9 dBi is a factor of 7.94. At 100 W, EIRP = 794 W; at 500 W, EIRP = 3970 W.
Power density at 7 m on boresight. S = EIRP/(4πd²), with 4π×49 = 616 m².
- 100 W: 794/616 ≈ 1.3 W/m².
- 500 W: 3970/616 ≈ 6.4 W/m².
Comparison. The ICNIRP general-public reference level around 144 MHz is of the order of 2 W/m² (occupational values are roughly five times higher). Confirm the current national implementation in both Greece and the Netherlands, because these values have been revised and some countries apply different averaging. On that basis, 100 W is under the reference level at 7 m, while 500 W is around three times above it - and the neighbouring upper windows, which look straight at the antenna, are well within the distance where the level would exceed 2 W/m². Solving 3970/(4πd²) = 2 gives d ≈ 12.6 m, so the 500 W case would need the antenna kept about 13 m from any accessible point on boresight, which a 15 m row of houses with facing windows does not provide.
Judgement. Use 100 W. The 40 % duty cycle does not rescue the 500 W case, because exposure limits for the public are not something to average away when people can be at the windows for long periods. If higher power were ever contemplated, it would need a documented assessment, a higher antenna with the beam tilted away, and physical restriction of access - not a contest weekend.