There are now 18 bidders remaining in Canada's biggest spectrum auction. RuralCom Corp., an upstart from Vancouver, finally reached price exhaustion in Round 182 on Thursday and called it quits.In ownership documents filed with Industry Canada at the application to participate stage, Robert Hillman, chair and CEO, held nearly 69% of the common shares in the company. The firm had deposited $80,000, the equivalent of two eligibility points.RuralCom placed a bid on the set-aside 10 MHz D-band Northwest Territories/Yukon/Nunavut licence in the first round and held that property for 130 rounds until Globalive Communications made a play for the licence. The two companies battled for the property with control seesawing back and forth for about 15 rounds until RuralCom reached price exhaustion at $80,000.Not wanting to leave the auction empty handed, the company shifted to the 5 MHz I-band licence in Northwest Territories/Yukon/Nunavut. Initially, RuralCom faced some opposition for this licence against SSI Micro Ltd., another provider intent on getting bandwidth in the Far North.After 40 rounds of fighting with SSI, the licence had topped the $90,000-mark, seemingly too rich for RuralCom.Meanwhile, SaskTel continues to battle hard for 40 MHz of bandwidth in its home province. The company currently has standing on bids on the A-band 20 MHz licences of Regina and Moose Jaw as well as the 20 MHz B-band provincial licence.Globalive also remains committed to filling out its spectrum portfolio with properties in British Columbia, Alberta and Ontario, with more recent plays for the Pembroke and Cornwall 10 MHz D-band licences.It's possible the auction could end as early as today. Thursday's last two rounds saw the number of new bids dip into single-digit range.After 27 days of bidding in the Advanced Wireless Services auction, total standing high bids have topped $4.19 billion. Vidéotron leads the new entrants with nearly $550 million in standing high bids. Globalive is second with $443 million and Data & Audio-Visual Enterprises Wireless (DAVE) has committed $242 million in standing high bids for third place. Rogers Communications tops the Big Three with nearly $950 million.