"Antonio" wrote in message
...
I always have wanted to know how much power are stations allowed to
operate.
I remember while living in Mexico, listening to XEWA 540AM, they used
to operate at 150,000 watts day and night, but now they are less than
that, probably 5000 watts or something.

150,000 day and night.

XEW 900 is well known, they use 250,000 watts and say they cover most
of North America.

They say nothing like that. The signal had been dropped to 100 kw for many
years, but due to high man made interference in Mexico City, they upped it
again to provide good coverage of the Mexico City metro area.

American stations use at most 50,000 watts and they are forced to
lower their power at night,

Some US 50's are 50 day and night; a few are non-directional all hours,
others go directional at night, others are directional at all hours. And
then there are many 50's in the daytime, that reduce to lower levels at
night... as low as 250 watts!

while at the same time, one station, I
think is in Mexico City, goes from 5,000 to 150,000 at nights.

Not so. In the 60's, XERF in Cd. Acuña, Coah., on 1570 only operated at
night as it's business was mail order and preachers. This was an exception.
It is now 15 kw day and night.

No Mexico City AM has higher night power than day power.

Any explanation would be appreciated and one question,
Is there any pros and cons of running that much power?
How about other countries, whats the most power a station can have?

Mexico: 250 KW. Most of Central America: 50 kw.
Colombia: 250 kw
Venezuela: 1,000,000 watts.
Chile, Argentina: 100 kw

Many European nations have 1,000,000 stations. Higher power is used in
several of the Arab nations.