Recordings Of IBOC (In-band, On-Channel) Derived Interference
Recording #1: 850 khz. interference by WWDB IBOC
Recording #2: 870 khz. interference by WWDB IBOC
Recordings #1 and #2 were kindly provided (January, 2005) by Russ Edmunds who indicates:
"These were made on the frequencies noted in the title when WWDB-860 was running demo
IBOC for the NAB convention about a year and a half ago. You can hear it for yourself on FM, as
92.5, 95.7, 96.5, to name a few are all IBOC."
Recording #3: 840 khz. interference by WWDB IBOC
Recording #4: 880 khz. interference by WWDB IBOC
Recordings #3 and #4 were also provided (January, 2005) by Russ Edmunds and demonstrate
the potent reach of IBOC interference, in this case +/- 20 khz. from the carrier signal running
IBOC. From Russ: "Here are a couple of more companion files showing the effects of WWDB's
IBOC on WCBS-880 & WVPO-840."
Recording #5: 1520 khz. interference by WSAI IBOC
Recording #5 was kindly provided (January, 2005) by Brett Saylor. From Brett: "Here's 1520 WKBW
with IBOC noise courtesy of 1530 WSAI (with the phaser on/off several times to show the
difference)."
Recording #6: 940 khz. interference by WPEN IBOC
Recording #7: 960 khz. interference by WPEN IBOC
Recording #8: 960 khz. interference by WPEN IBOC - shut off
Recordings #6, #7 and #8 were kindly provided (February, 2005) by Russ Edmunds. Recording #6 is a
sample of WPEN's IBOC hash on 940 khz. mid-afternoon. Recording #7 is a sample of WPEN's IBOC
hash on 960 khz. during the same time period. Recording #8 captured the cessation of WPEN's IBOC
hash on 960 khz. in the afternoon. This latter event can be seen visually here (image also provided
by Russ).
Recording #9: WOR IBOC
Recording #9, obtained on 10-Sep-05, starts at 1730 local with my receiver set to 730 khz. After 10 seconds
on this frequency, I went down in frequency in 10 khz. steps every 10 seconds until I reached 690 khz. Note
the clear presence of WOR’s IBOC interference (audible white noise) on 720 khz. and 700 khz. After sitting
on 690 khz. for 10 seconds, I then climbed back up to 730 khz. again in 10 khz. steps every 10 seconds.
Some details:
Receiver = Drake R8B
Band width = 6.0 khz.
Mode AM
Antenna = MFJ-1024 Vertical whip with 0 dB attenuation and maximum gain
Recorded using Total Recorder (Version 5.2) on an IBM Thinkpad T30 as a .wav file and converted to an
.mp3 file using MP3 WAV Converter Version 3.05.
Recording #10: KPDQ, 800 khz.
Recording #10 (kindly sent by Dennis Vroomski of Salmon Creek, WA) was recorded at 2132 PDT on 29-Sep-07
and reveals KPDQ (800 khz.; Portland, OR) being noticeably affected by the IBOC hash of KGO (810 khz.; San
Francisco, CA). Note that Dennis is located 18 miles from KPDQ and 563 miles from KGO.
Here’s a screen capture of WILM’s IBOC signal (1450 khz.; Wilmington, DE) from the evening of December 18,
2007. The interference to the first adjacent frequencies can be clearly seen (receiver = RFSpace SDR-IQ).
