Aug 21 (Reuters) - The rouble weakened past 94 to the dollar on Monday but traded relatively steady after one of its most volatile weeks all year, when an unscheduled rate hike to 12% and support from exporters' foreign currency sales sparked a recovery from beyond the 100 mark.

By 1126 GMT, the rouble was 0.6% weaker against the dollar at 94.30 and had lost 0.9% to trade at 102.81 versus the euro. It had shed 0.5% against the yuan to 12.89.

The Bank of Russia's 350-basis-point hike followed the rouble's slide to a near 17-month low of 101.75 to the dollar, hit last Monday. The currency strengthened to an over two-week high of 92.55 on Thursday.

Analysts said more measures may be needed to return the rouble to the 80-90 range authorities have deemed acceptable, but subsequent reports that capital controls may be reintroduced seemed to be having the desired effect.

Authorities were discussing bringing back the compulsory sale of foreign currency revenues for exporters, five sources told Reuters. Two sources subsequently said FX sales were being increased informally, with exporters being told to sell as much as possible and provide weekly updates.

Russia could support the rouble in other ways, though none are particularly favourable.

"The authorities are clearly pursuing a goal of 'knocking down' the dollar exchange rate, which has gone far beyond reason, understanding that the people will not like double-digit inflation or lower living standards and other 'delights' that inevitably follow the devaluation of the national currency," said Evgeny Kogan, professor at Russia's Higher School of Economics.

As the end of the month approaches, the rouble also has the support of tax payments, where exporters usually convert foreign revenues into roubles to meet local liabilities.

"The rouble will be supported by the approaching peak of the tax period," said Alor Broker's Alexey Antonov in a note. "However, it's not worth hanging especially strong hopes on that, as the nature of trading clearly showed that exporters increased their FX sales last week."

Brent crude oil, a global benchmark for Russia's main export, was up 1.1% at $85.745 a barrel.

Russian stock indexes were higher.

The dollar-denominated RTS index was up 0.5% to 1,052.3 points. The rouble-based MOEX Russian index was 1.2% higher at 3,148.5 points.

(Reporting by Alexander Marrow; Editing by Angus MacSwan)