Re: [IRCA] [ABDX] IBOC carrier precision

[Barry McLarnon <bdm@xxxxxxxxxx>]

On Monday 09 February 2009 19:23, Brandon Jordan wrote:
> I know there are some real IBOC experts on the lists and have a
> question. Are most, if not all, IBOC stations precisely
> on-frequency? I believe I read that IBOC required extreme frequency
> precision of the carrier frequency? I am looking for MW stations to
> help in accurate calibration of SDR receivers in order to measure
> frequency offsets, and am hoping my memory regarding this is
> accurate.
>
> On a positive note, I calibrated the G313e to IBOC WLAC 1510 kHz,
> and was then pleased to note that IBOC KMOX's carrier measured
> exactly 1210.0000 khz.

There are actually two levels of precision specified in the AM IBOC 
standard.  Level I ("network synchronized") assumes the use of GPS 
synchronization, and specifies that the carrier frequency be accurate 
to within +/- 0.02 Hz.  Level II ("non-network synchronized"), on the 
other hand, requires only +/- 2.0 Hz accuracy.  The standard 
recommends that Level I precision be used "to support numerous 
advanced system features", but it is not a requirement.

The majority of AM IBOC stations appear to meet the Level I spec and 
are therefore good frequency references, but there are exceptions.  
One notable exception is WQEW-1560, which is on 1559.9983 or 
thereabouts.

Barry

-- 
Barry McLarnon  VE3JF  Ottawa, ON
_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx