Clear Channel Communications, the largest radio station network in the US, today reported lower earnings that it said were due to its deliberate sacrifice of on-air advertising time.

The "Less is More" strategy was introduced last year in a bid to attract listeners who had been turned off by too many adverts.

The group, which also owns a massive billboard business in Britain and a worldwide concert group, said second-quarter earnings fell to $220.7m (£123.7m) from $253.8m a year earlier.

The advertising climate was "less than ideal", it added.

"With just two complete quarters of 'Less is More' behind us we are seeing positive trends," said Mark Mays, the president and chief executive officer.

"Early ratings results from the important spring ratings book show that ratings and time spent listening are on the rise."

The group reported revenues of $2.46bn in the second quarter, 1% down on the $2.49bn report a year ago.

Clear Channel, based in Texas, said revenue from radio broadcasting fell 6.5%, while billboard and other outdoor advertising rose 7%. Revenue from the live entertainment division, which the company plans to spin off, fell 1%.

The company also boosted its share buyback plan by $692m, meaning by next year it will have bought back shares worth a total of $1bn.

Commercial radio groups in the US are fighting the impact of satellite radio group Sirius, which gives listeners 120 radio stations for $7 a month - all of them advert free.

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