When The VOA Interferes With Itself On Shortwave

[SomeRadioGuy]

What happens when VOA's Sao Tome & Principe site signs on the Hausa service on 9470khz 2 minutes early while the French service is still kicking on 9470 as well? You get english hit music with a french announcer colliding head on with the "Yankee Doodle" sign on.

Fast forward to 2 minutes 40 seconds and listen for a few seconds to hear it happen, I recorded this a few weeks ago at my Alaska QTH

VOA 9470khz French 2025UTC Sat Oct 14, 2023 BOT collides with STP.MP3

 

[Kelly A]

What happens when VOA's Sao Tome & Principe site signs on the Hausa service on 9470khz 2 minutes early while the French service is still kicking on 9470 as well? You get english hit music with a french announcer colliding head on with the "Yankee Doodle" sign on.

Fast forward to 2 minutes 40 seconds and listen for a few seconds to hear it happen, I recorded this a few weeks ago at my Alaska QTH

VOA 9470khz French 2025UTC Sat Oct 14, 2023 BOT collides with STP.MP3

Somehow I doubt anyone else cares, let alone notices other than DX'ers. And they aren't the target audience anyway so...

 

[SomeRadioGuy]

Somehow I doubt anyone else cares, let alone notices other than DX'ers. And they aren't the target audience anyway so...

I absolutely agree and I was probably the only one listening over the air who heard this.

 

[RadioFan2J3]

What happens when VOA's Sao Tome & Principe site signs on the Hausa service on 9470khz 2 minutes early while the French service is still kicking on 9470 as well? You get english hit music with a french announcer colliding head on with the "Yankee Doodle" sign on.

Fast forward to 2 minutes 40 seconds and listen for a few seconds to hear it happen, I recorded this a few weeks ago at my Alaska QTH

VOA 9470khz French 2025UTC Sat Oct 14, 2023 BOT collides with STP.MP3

Paul, obviously someone made a mistake.

Without seeing the program schedule for that day a few weeks ago, I'd not be able to pinpoint where the error occurred.

Here is my take - the frequency branch in Washington should have noticed the use of 9470 at two sites, back-to-back time slots, one ending the program (assume that was Botswana) and then the beginning of a new program (assume that was Sao Tome.)

Normally, the program charts sent out to the stations should have have an instant-on for 9470 at Sao Tome, no sign-on and very well should have a DCI - drop carrier immediately at Botswana, with no sign-off.

What the casual listener would have heard was the end of the French program, then dead air for perhaps upwards of 30 seconds and then the Hausa program.

The other possibility is that Sao Tome ran a sign-on on 9470, either simply messing up or misreading the program schedule.

Did you notice this program overlap only once or for several days, same time, same frequency?

 

[davideduardo]

Paul, obviously someone made a mistake.

Without seeing the program schedule for that day a few weeks ago, I'd not be able to pinpoint where the error occurred.

Here is my take - the frequency branch in Washington should have noticed the use of 9470 at two sites, back-to-back time slots, one ending the program (assume that was Botswana) and then the beginning of a new program (assume that was Sao Tome.)

Normally, the program charts sent out to the stations should have have an instant-on for 9470 at Sao Tome, no sign-on and very well should have a DCI - drop carrier immediately at Botswana, with no sign-off.

What the casual listener would have heard was the end of the French program, then dead air for perhaps upwards of 30 seconds and then the Hausa program.

The other possibility is that Sao Tome ran a sign-on on 9470, either simply messing up or misreading the program schedule.

Did you notice this program overlap only once or for several days, same time, same frequency?

The real issue is whether the two signals overlap in the intended or "target" zone. I know of some cases where SW broadcasters have used the same frequency for two different zones simultaneously.

 

[SomeRadioGuy]

Paul, obviously someone made a mistake.

Without seeing the program schedule for that day a few weeks ago, I'd not be able to pinpoint where the error occurred.

Here is my take - the frequency branch in Washington should have noticed the use of 9470 at two sites, back-to-back time slots, one ending the program (assume that was Botswana) and then the beginning of a new program (assume that was Sao Tome.)

Normally, the program charts sent out to the stations should have have an instant-on for 9470 at Sao Tome, no sign-on and very well should have a DCI - drop carrier immediately at Botswana, with no sign-off.

What the casual listener would have heard was the end of the French program, then dead air for perhaps upwards of 30 seconds and then the Hausa program.

The other possibility is that Sao Tome ran a sign-on on 9470, either simply messing up or misreading the program schedule.

Did you notice this program overlap only once or for several days, same time, same frequency?

I have actually heard this happen several times, and if i recall correctly... several times in this particular 9470 and timeslot, more then once.

an engineer i know whos done work on the antenna arrays in STP and BOT passed on word of what id heard

I've noticed the yankee doodle sign on/off only form a random smattering of sites.. but im told it gets inserted in the program feed, not at the site. i think ive noticed the sign on/off mostly on french, sometimes on hausa and rarely on english feeds

 

[SomeRadioGuy]

The real issue is whether the two signals overlap in the intended or "target" zone. I know of some cases where SW broadcasters have used the same frequency for two different zones simultaneously.

@DavidEduardo CGTN/CRI has that now.. 11770 at 0100 to 0200
one broadcast from one site is in english
one is in mandarin

one targets "south asia" pone targets "southeast asia"

But in this case, i think its just them being sloppy and not caring or checking, SW beam widths arent usually too tight.. so theres got to be overlap there

 

[Mediafrog+]

But in this case, i think its just them being sloppy and not caring or checking, SW beam widths arent usually too tight.. so theres got to be overlap there

Poor coordination among transmitter sites is the culprit here.

OTOH the BBC owned facilities on Ascension Island and Oman have been very good about precise frequency changes and site handoffs. Other leased sites used by the BBC can sometimes have similar issues to what you heard with VOA.

More recently designed SW transmitter sites are fully automated, with program feed switching, transmitter power ups and downs, frequency changes, and antenna azimuth changes all driven by computers at precise times. Such facilities often don’t require any human staff to be present while in operation. Of course everything has to be properly programmed and coordinated.

 

[Kelly A]

Paul, obviously someone made a mistake.

Oh, blame it on 'Golden Eagle'.

 

[SomeRadioGuy]

Poor coordination among transmitter sites is the culprit here.

OTOH the BBC owned facilities on Ascension Island and Oman have been very good about precise frequency changes and site handoffs. Other leased sites used by the BBC can sometimes have similar issues to what you heard with VOA.

More recently designed SW transmitter sites are fully automated, with program feed switching, transmitter power ups and downs, frequency changes, and antenna azimuth changes all driven by computers at precise times. Such facilities often don’t require any human staff to be present while in operation. Of course everything has to be properly programmed and coordinated.

Once in a blue moon, I've heard the BBC goof it up when a frequency is used at another site the next hour, with it being the same frequency as the last.. but the few times ive heard it, its been a carrier coming up like 20-30 seconds early, but no audio until 00:00

ive heard SEAMLESS transitions from one site to another on the same frequency with not a blip of interuption in audio

 

[boombox4]

@DavidEduardo CGTN/CRI has that now.. 11770 at 0100 to 0200
one broadcast from one site is in english
one is in mandarin

one targets "south asia" pone targets "southeast asia"

But in this case, i think its just them being sloppy and not caring or checking, SW beam widths arent usually too tight.. so theres got to be overlap there

There probably is little to no overlap in the actual target areas. If you're in South Asia you're probably going to hear the English one quite well, and if you're in SE Asia, you'd probably hear the Mandarin broadcast clearly enough. The two transmitter sites (Kashgar in far Western China, and Nanning in SW China) are roughly 1000-1500 miles from each other.

Our distance from both transmitters (you're in AK, I'm in WA) makes it easier for us to hear both transmissions at the same time.

So I wouldn't bet on them being too sloppy about this. At the same time, one wonders why they wouldn't just find a separate frequency for both, but it's probably not necessary.

As you said, there probably is some overlap in places like Burma or Laos, and other regions out of the target zones, but the targetted audiences probably don't hear much, if any overlap, especially when the transmissions are 100KW.

 

[RadioFan2J3]

I have actually heard this happen several times, and if i recall correctly... several times in this particular 9470 and timeslot, more then once.

Okay, well, that is interesting.

I've noticed the yankee doodle sign on/off only form a random smattering of sites.. but im told it gets inserted in the program feed, not at the site. i think ive noticed the sign on/off mostly on french, sometimes on hausa and rarely on english feeds

To the best of my knowledge, those Yankee sign-on and sign-off segments are not part of the program feed from Washington. It is all a function at the local transmitter site.

 

[SomeRadioGuy]

Okay, well, that is interesting.




To the best of my knowledge, those Yankee sign-on and sign-off segments are not part of the program feed from Washington. It is all a function at the local transmitter site.

I was told the opposite BUT ... while i havent taken note of what sites ive heard them on, memory seems to recall its mostly botswana and i think.. Sao tome

 

[RadioFan2J3]

Oh, blame it on 'Golden Eagle'.

Ah, now I understand the reference!!