KFUO: ANALOG VS. IBOC

To illustrate how spectrally inefficient IBOC-DAB is vs. analog, KFUO (850 kHz) Clayton, MO is being used as an example. The following bandscans of the 800-900 kHz portion of the AM dial was taken using consumer-grade analog receivers, instead of an expensive IBOC-DAB receiver.

 

LOCATION: Hazelwood, MO

10 miles northwest of Concordia Seminary

Receiver: General Electric Superadio III

 

Dial       Heard with KFUO in analog mode            Heard with KFUO in IBOC mode

800       KREI Farmington, MO (clear)                  KREI Farmington, MO (clear)

810       WHB Kansas City, MO (clear)                WHB Kansas City, MO (with moderate KFUO interference)

820       WCSN Chicago, IL (weak)                      Wiped out by KFUO’s IBOC sidebands

830       KOTC Kennett, MO (fair in Stereo)           Wiped out by KFUO’s IBOC sidebands

840       In both instances, this frequency is wiped out by KFUO’s sidebands

850       KFUO has excellent sound                     KFUO’s sound quality is tinny, at best

860       In both instances, this frequency is wiped out by KFUO’s sidebands

870       WINU Shelbyville, IL (weak)                    Wiped out by KFUO’s IBOC sidebands

880       WIJR Highland, IL (clear)                        WIJR Highland, IL (with severe KFUO interference)

890       WLS Chicago, IL (good)                          WLS Chicago, IL (very poor with KFUO interference)

900       KFAL Fulton, MO (clear)                         KFAL Fulton, MO (clear)

 

In the case of WHB, WCBW and WLS, KFUO’s IBOC sidebands are interfering with their signals. (QRM is another term for interference.) In this case, the stretch between 820 and 870 kHz is wiped out by the IBOC sidebands.

 

Now, here’s a second location…much closer to KFUO’s transmitter site.

 

LOCATION: 7700 block of Clayton Road, Richmond Heights, MO

One mile west of Concordia Seminary

Receiver: Jensen AM/FM receiver with CD player

 

Dial       Heard with KFUO in analog mode            Heard with KFUO in IBOC mode

800       KREI Farmington, MO (clear)                  KREI Farmington, MO (with interference from KFUO’s IBOC sidebands)

810       WHB Kansas City, MO (clear)                Wiped out by KFUO’s IBOC sidebands

820       Image from KFUO                                  Wiped out by KFUO’s IBOC sidebands

830       KOTC Kennett, MO (fair)                         Wiped out by KFUO’s IBOC sidebands

840       In both cases, KFUO’s sidebands make this frequency unusable

850       KFUO with excellent audio quality           KFUO with tinny audio quality

860       In both cases, KFUO’s sidebands make this frequency unusable

870       In both cases, KFUO’s sidebands make this frequency unusable

880       WIJR Highland, IL (clear)                        WIJR Highland, IL (nearly inaudible due to KFUO’s IBOC sidebands)

890       WLS Chicago, IL (fair)                            Wiped out by KFUO’s IBOC sidebands

900       KFAL Fulton, MO (fair)                           KFAL  Fulton, MO (with severe KFUO interference)

 

In this case, KFUO is wasting more spectrum space at closer range. Analog radio is more efficient, from a spectral point of view, than IBOC (or any other digital form of radio). This proves, once and for all, that AM frequencies are not suited to digital radio (and neither are shortwave and FM, for that matter). For more on the truth about IBOC-DAB, go to the Free Press Web site.

 

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