* Deal would help KPN cut debt
* KPN hopes to find buyer for BASE in September
* Five companies submitted non-binding bids-sources
* KPN could keep BASE if bids are too low
By Sophie Sassard and Simon Meads
LONDON, Aug 9 (Reuters) - KPN, the struggling Dutch telecom operator in the sights of Mexican tycoon Carlos Slim, has drawn a string of bids for its Belgian mobile unit BASE, which could help it raise up to 1.7 billion euros crucial to cutting its debt.
Belgium's media group De Persgroep, cable company Telenet and private equity firms Blackstone, Providence and Cinven all submitted non-binding bids last week, people familiar with the process said.
KPN is hoping to find a buyer in September although the sale could be called off if no satisfactory bid was received, Chief Executive Eelco Blok recently said.
"It's been my worry since the beginning", said a person close to one of the bidders.
KPN kicked off the sale of BASE, the smallest of Belgium's three main operators behind Belgacom and Mobistar , in July when it also cut its 2012 dividend by more than half and set about tackling its debts.
KPN's new 28-percent shareholder America Movil, which belongs to Carlos Slim, has also expressed its preference to keep BASE under KPN's umbrella.
Private equity firms could find it hard to meet KPN's price expectations as BASE was relatively well-managed compared to other sector peers and offers limited growth prospects, leaving little room for manoeuvre to make it more profitable.
Bidders said BASE could fetch between 1.4 billion and 1.7 billion euros ($1.7-2.10 billion) or 5-6 times its estimated earnings before interest, tax, depreciation and amortisation of 280 million euros for 2012, the sources said.
This would be lower than recent deals such as Orange Switzerland's sale to Apax for 6.5 times 2011 EBITDA in February or CVC's acquisition of Swiss rival Sunrise the previous year for about 6 times EBITDA, deals which have stood out as some of largest buyouts since the credit crisis.
Telenet, Belgium's largest cable operator, is hoping to team up with a private equity firm in the coming weeks in order to share the investment, two of the people said.
Telenet held constructive talks with Blackstone but did not have time to broker a partnership by the August 1 bidding deadline, those people added.
The Dutch telecoms group, in which Carlos Slim's America Movil owns a near-28 percent stake, is suffering a decline in revenues in its home market because customers are sending fewer high-margin text messages, using the Internet to do this instead.
The trend is sweeping the industry, brought about by the rise of smartphone device makers like Google and Apple, whose messaging apps allow users to avoid charges for voice and text.
KPN, Providence and Cinven declined to comment, while Blackstone, Telenet and De Persgroep were not available for comment. ($1 = 0.8093 euros)