Our national legislator proposes to reduce the maximum power output in the high end of 23cm to 20 watts.The high end is the ssb cw digital part. Reason given: possible interference with airport radar above 1300MHz. How is the situation in other countries?  73  Johan  ON4IQ

Consult-2018-D3 arguments against change of maximum power limit on 1260-1300MHz (by ON5GS)

(automatic translation from Dutch message)

Contact point:

Philippe Appeldoorn, First Engineer Adviser (tel 02 226 88 51)
Ben Deschacht, acting advisor (tel 02 226 88 93)

Dear Sir,

Please allow me to comment on the proposal to change the maximum power between 1260 and 1300MHz in the amateur band to 20W.

I am active with moonbounce operation (Earth-Moon-Earth) at 1296MHz, with a maximum power (special permission) of 200w in a self-built dish of 6 meters in diameter.

My arguments against changing the maximum power:

- there is possibility of interference from amateurs in the new military L-band radars at 1300MHz. This is to be prevented by reducing the upper band segment 1260-1300MHz to 20w.

- the CW / SSB (tropo and EME) is around 1296.200MHz. Of these, the amateurs mainly use during weekends, during tropo openings and at good lunar phases.

- The probability that an EME station interferes with a radar is extremely small because the amateur always directs his dish (three meters or more) towards the moon with a large elevation angle; the low opening angle makes the radiation pattern such that there can never be a false signal. My suggestion is to completely exempt the EME stations from this 20 watt rule.

- An amateur who is out for "tropo" connections directs his antenna to the horizon. Yagis or a dish are used here. The probability of malfunctions is greater with poor management, although the probability of exceeding 1300MHz is really small because the amateurs on these bands know what they are doing. The UBA has also been organizing activity contests for the higher amateur bands, including 23cm, since time immemorial (1956 !!). These are usually held in groups by enthusiastic amateurs. Reducing the power to 20w will be the reason for most people to no longer participate, as the distant "DX" stations will no longer be within reach. I therefore propose to exempt these activity weekends (first weekend of March, May, July,October and November Marconi test) from the 20w rule. In the surrounding countries there is also a lot of activity during these weekends.

A proposal may be to grant a special "high power" license to amateurs active on these frequencies as has already been done in a "special permission appendix" so that the maximum power of 200 watts is retained.

This can possibly be linked to a minimum elevation angle of 10 degrees, so that radars remain safe.

Hopefully you keep these arguments before we lose our wonderful hobby.

Kind regards and 73!

ON5GS Dirk Reyners


Note by OK2KKW web page editor (OK1VPZ):

Try to explain them the basic princip of the amateur radio operation -> make a contact with other amateur radio station. In area, where the EMC with radar could be a potential issue, the receiver of the amateur radio station will be overloaded by strong radar pulses. It mean -> in case of impossible reception nobody from amateur radio operators will transmit there, because due to overloading of very sensitive receiver no weak signal amateur radio contact is possible. Such automatic prevention is the best and natural defence of any radar interference -> it mean such interference is by blocking of amateur radio receivers out of possibility. And above it -> such regulator concerns has always simple solution: limit present full legal power to the narrower wide slot - for example from 1296 to 1297MHz only. In such case the possible interference with radar on 1300MHz will be limited almost to zero.