KBRT Nearly Eliminates Upper HD Side Band

[Link]

Is KBRT running the narrow analog bandwidth with their IBOC? I think they must be to decode off one side band. In Chicago I think only Univision ran that narrow bandwidth. The 50KW boys and CC's 1690 seem to run off a wider bandwith setting that requires both sidebands to decode.

 

[davideduardo]

BTW, this frequency changing made me go through some of your
yearbooks and I noticed that after 1450, KFMB first moved to 550,
then 540 (prior to 760). Or was "550" a nefarious typo--as were
known to haunt the Taishoff tomes for years--and it actually was
540 after 1450 and before 760?

I suspect that 550 was a typo. Obviously, it would not have worked with Phoenix and Bakersfield for starters. I remember hearing 540 in Ecuador around '65 when the channel was not in use much in Latin America... that much I can verify myself!

 

[Carmine5]

Just as a follow up to this topic, Crawford's latest newsletter describes in detail how they accomplished eliminating the upper side band (an interesting read if you can get past the newsletter's snideness over KFMB's complaint):

http://www.crawfordbroadcasting.com/~cbc/Local_Oscillator/January 2010 Local Oscillator.pdf

Their conclusion:

"AM HD works just fine with only one set of digital primary carriers," although they did mention a problem with spectral regrowth. BTW, KBRT uses a Nautel XL-series transmitter.

c5

 

[JohnnyElectron]

When I had the pleasure of visiting Catalina Island back in 2000, KBRT has some nice sounding C-Quam AM stereo audio - obviously they now have HD. But, I wonder if they're able to still have stereo audio on HD radio with only 1 sideband at full power or if they can only run mono HD and analog at only 5KHz mono?

 

[Savage]

If I understand it correctly - and I think I do - the DSB arrangement only provides redundancy in the event of loss of one or the other sideband. All the information for stereo HD decode is contained in each sideband.

The analog bandwidth - 5 kHz or otherwise - at least theoretically shouldn't have any effect on stereo. But it will indeed make for a muddy, lackluster sounding AM analog mono product.

 

[Big 121]

Re: KBRT Nearly Eliminates Upper HD Side Band/KFMB in Ecuador?

.

BTW, this frequency changing made me go through some of your.I suspect that 550 was a typo. Obviously, it would not have worked with Phoenix and Bakersfield for starters. I remember hearing 540 in Ecuador around '65 when the channel was not in use much in Latin America... that much I can verify myself!
[/quote]

Ahhh yes, KFMB pounded out. To Yuma AZ. daytime. On Katella , near Disneyland, they had bus bench ads. I could see the tower lights from front porch:
located on Zion Ave, 2 towers in east/west orientation. According to a buddy who worked in their eng. dept., they got many reception reports from Guam,
Australia, HI, and so forth. You see, the DAN pattern dumped maybe 70% directly west into the Pacific, 5 miles away. CBK Canada had the then "Clear
Channel". Also being protected was XEWA, San Luis Potosi, Mex. at over 100kw. Being almost 900 miles closer to Ecuador, XEWA should have overridden
any feeble wayward femtovolts KFMB was leaking off the back of the pattern... Dominican Republic's coastal 540 water path would be a problem also.
MAYBE using a 2000' longwire, and a nuclear powered HQ129, and Professor Browns' Flux capacitor, KFMB could have been heard in Ecuador....
.... Big 121

 

[stacker]

With AM HD performing as poorly as it does, you have to wonder why Crawford just doesn't turn it off and get back to business of serving the listeners with the best signal possible. Hmmm.