Nautel-Transmitters-AM-MDCL-Power-SavingsModulation-Dependent Carrier Level (MDCL) control technologies or algorithms, long used by international broadcasters operating high-powered AM transmitters to reduce transmitter power consumption, is now FCC approved for use by AM stations in the U.S.
To implement MDCL technology, AM licensees need a waiver of rules, but the bureau has set up procedures to seek the waiver and has indicated it would approve requests that use Nautel options. See the FCC Public Notice. In April 2013, the NRSC provided a new AM MDCL Usage Guideline; see NRSC-G101.


Nautel has made this power-saving technology FREE in its NX Series transmitters since the first NX rolled out in 2008.
Tim Hardy, Nautel’s Head of Engineering and a longtime advocate of such power-saving technologies, urged the rest of the Nautel management team not to charge extra for MDCL technology but to include it as a free, standard pre-installed software feature (i.e. not an optional circuit board) in all NX Series transmitters (now available in models from 5 kW up to 2 MW).

Quick & Easy NX Implementation


Enabling MDCL on your NX transmitter takes mere seconds.
Using Nautel’s award-winning Advanced User Interface (AUI):

  • Select ‘Menu’
  • Select ‘Presets’
  • Select ‘Analog Settings’
  • Select ‘Dynamic Carrier Control’
  • Select one of the options (all provide significant power savings but Nautel recommends AMC due to its minimal audible impact) and click ‘Load’

Watch a 1-minute instructional video now >>

Simple Upgrade for XR, XL & ND

For XR Series transmitters – Upgrade to MDCL is quite simple. If your system is operating with HD Radio™ technology, it’s simply a matter of upgrading the Exporter Plus software to include the MDCL package; contact Nautel Customer Service for this »
If your system is using an older version Exporter or NE-IBOC(AM) unit, it may be necessary to upgrade to an Exporter Plus; contact your Nautel Sales Rep for pricing »
For XR Series transmitters that are NOT using HD Radio™ technology – An external DCC (Dynamic Carrier Control) unit will be required. Installation is very simple and cost is minimal; contact your Nautel Sales Rep for pricing »
For older ND and XL Series transmitters – Again if you are operating with HD Radio™ technology, enabling MDCL is the same as with the XR Series (above). It’s simply a matter of ensuring that you are using an Exporter Plus with the proper software loaded, or upgrading the Exporter as required.
For ND and XL Series transmitters that are NOT using HD Radio™ technology – Some upgrades are required. These will involve: replacing the RF Drive and PDM boards in the exciter section of the transmitter; installing an interface board to connect to the DCC unit; then installing (in a separate rack) and connecting the DCC unit. Pricing must be done on a case by case basis for these situation; contact Nautel Customer Service for pricing »

Additional Power Savings

Overall efficiency of the NX25 and NX50 is typically 88% or better. NX100 and above achieve 90% efficiency.
This means less energy is wasted as heat, which reduces cooling and ventilation costs. Savings can amount to tens of thousands or even hundreds of thousands of dollars over the life of your transmitter depending on its size and your local power rates.


MDCL Station Examples

MDCL Operation Is a Winner for High-Power AM, Radio World 4/18/2012
Multiple Customers Use MDCL to Huge Success, Apr 3, 2012
Crawford Sees ‘Very Tangible Savings’ With MDCL, Radio World 3/6/2012
Customer Story: Crawford Saves 21% to over 40% With MDCL
Crawford Saving Money With MDCL, Radio World 02/01/2012
KSPN Is Running MDCL in L.A., Radio World 01/06/2012
KLTT(AM), Denver is Employing MDCL on Nautel NX50, Radio World 01/05/2012
A Break for Your AM Station’s Power Bill, Radio World 9/13/2011
Alaska Test Produces Lower AM Power Costs, Radio World 4/5/2011

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