Creating an Ascending Clock Auction (ACA)


TagsAuction software, help

Common features

The ACA shares several common features with the other auction types:

  • Title
  • Description
  • Auction start time
  • Price units
  • Bidders
  • Round duration
  • Break duration
Setting these up is described in the Common features page.

Specific requirements of the ACA

The ACA has specific features as well as a particular way of using common features:

Assignment stage duration

assignment stage

As the clock stage of the ACA sells generic rather than specific lots these is usually an assignment round to see if any bidder wishes to pay more to acquire a licence in a specific frequency range.

This box allows the administrator to specify the length, in minutes, of that assignment round. If you are only selling a single lot there is no need for an assignment round


ACA lots



Here you should give a name to each generic lot, specify how many lots are available and give the start price, increment and eligibility points. In the first example above there are three 800 MHz lots available, bidding will start at 500  and rise at an increment of 75 when there is excess demand.

If you wish to set a spectrum cap then you need to put each generic lot into a category, represented by a letter. In the example above 800 MHz is category A and 2.6 MHz is category B.

Spectrum Caps

ACA caps

A spectrum cap allows the administrator to specify a maximum amount of bandwidth which can be bought in a particular category. This can be expressed as either paired or unpaired spectrum. In the example above bidders can buy a maximum of two category A 800 MHz licences (2 x 10 Mhz paired) or four category B 2.6 MHz licences (4 x 20 Mhz paired).

If a bidder tries to exceed their spectrum cap the software will prevent them making the bid.