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KBAQ Phoenix - is noise due to IBOC from HD Radio?

In Chandler I get a strong signal from both KBAQ and KJZZ but KBAQ is noisier. The noise goes away in mono.

I've experienced this on both tube and solid-state tuners, three of which are freshly aligned. I'm suspecting in-band-own-channel noise due to HD radio, but I don't have the instrumentation to confirm this. If any RF experts out there have data, I'd really like to know. I'm planning on building an FM decoder and the design depends on the answer.

I wasn't listening to FM much when HD radio got turned on; did anyone in the Phoenix area notice a change? Please let me know.

I've volunteered for both stations, they're in the same building; I don't
believe the source quality is different. KBAQ's online stream is quiet but not the high bitrate I would like.

Have others experienced this problem with KBAQ? Another FM user here in the East Valley reports KBAQ is noisier on several tuners he has tried. Another user in Pinnacle Peak says he does not have that problem.

Thanks for your observations!

Regards, HG
hifigeezer
conelrad
1 posts
 
Hi HG,

What you are hearing is most likely multipath noise, caused by slightly different signal paths causing time shift errors at your receiving antenna.

When I moved KBAQ back to South Mountain from the White Tank site many listeners were very happy with the increased signal strength, but many buildings in the Southeast valley caused a noticeable increase in multipath noise.

They are already using a circularly polarized antenna for transmission to minimize this bad effect of the land, and unfortunately, there is nothing more the station can do.

Your best action might be to re-orient your antenna for best quieting on KBAQ. If you do not already have a directional antenna for your receiver, I highly recommend an outdoor one.

Dennis Gilliam
Retired Chief Engineer
KJZZ-KBAQ
hifigeezer OP
37 posts
 
Thank you Mr. Gilliam! I'm sorry I didn't see your reply sooner. I finally bought an oscilloscope to check for mulipath. I don't see much from my attic antenna but I may do some experiments with some rabbit ears.
hifigeezer OP
37 posts
 
Thanks again to Mr. Gilliam. Here's the email I got today (October 25, 20012) from KBAQ:

Dear Sir,

Thank you for your inquiry concerning reception of KBAQ in the Chandler area. KBAQ is located on South Mountain where a new facility was constructed in 2010 and the station went HD at the same time. At your location in Chandler near the 101 and 202 intersection there should be no difficulty in receiving KBAQ in either analog or HD mode. Thank you again for your inquiry and for listening to KBAQ

Best Regards,

--
Dave Atkins
Chief Engineer
KJZZ/KBAQ
Rio Salado College
2323 W. 14th. St,
Tempe, AZ 85281
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