Tag Archives: Shortwave Bandwidth

China Radio International’s overwhelming AM bandwidth via Havana

Scott-Marine-SLR-M-Dial

This morning, I listened to Radio Australia on 9,580 kHz with my WWII era Scott Marine Radio SLR-M (above).

Radio Australia provides a reliable, strong signal into North America every morning and it’s where I typically tune for the morning news at the top of the hour.

China Radio International also fires up on the adjacent frequency of 9570 kHz around 1200 UTC–their signal is also incredibly strong here as it’s relayed from Radio Havana Cuba at 250 kW. CRI’s bandwidth is almost always wider than 10 kHz–indeed, it’s often 20 kHz–which means that it completely wipes out any average adjacent signal.

Indeed, when I’m testing selectivity on portable shortwave radios, I’ll often tune to Radio Australia and wait for CRI to fire up on 9570 kHz. If the portable radio can still lock onto Radio Australia after CRI is on the air–or, better yet, if an upper side band sync lock can eliminate all traces of CRI–I know the receiver has decent selectivity.

This morning, when CRI began transmitting at 1200 UTC, their signal completely wiped out every trace of Radio Australia. Though the SLR-M’s narrow AM filter is still quite wide, it can typically cope with the adjacent CRI carrier.

I fired up the TitanSDR to see what CRI’s signal looked like on a spectrum display–here’s what I found:

China-Radio-International-Bandwidth

CRI’s AM bandwidth was 30+ kHz wide! 

In my book, that was an abusive use of the band.

This was, by no means, an isolated event. It was just particularly annoying for me this morning as I was enjoying a good cup of coffee and the morning ABC news.

I’ll send a message to CRI and RHC about this, but I have my doubts anyone will take action.

Okay–sorry about the rant!

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