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Frequency deviation world record?

simsnet

simsnet

One of my local translators runs modulation on full blast, stepping on 99.7 and 100.1 all the time.

Could this be a record? 🙃

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We hear a translator here in SW Florida that sounds awful too but it's because the audio feed is so high it clips not over modulation. It's a talk format. Nothing as bad as yours
 
When testing modulation you need to be very careful that the signal going into the modulation analyser is good. Low level (or excessive level) will make the modulation look very high because of noise/distortion. Likewise, high levels on nearby channels can also make the modulation look high. Anything that degrades the signal into the analyser will make the modulation appear high. The only certain way to measure deviation is to directly connect to the transmitters RF monitor port with a suitable attenuator/pad. Having said that, there are plenty of stations in the world that have crazy high level modulation.
 
Just curious, In the event, when the FCC does a "field" check of stations, what do they use. Is the "van" a myth now? The last write up of a station I saw on the site, the FCC inspector saw they had a 3 bay instead of a 2 bay antenna. Easily done with binoculars or a camera with proper lens.

I never worried about the Commission because I worked for folks who felt staying legal was a cost of doing business. Except for the license test, I never met a FFC employee.
 
I have seen stations with higher modulation levels on my country. That one is around 260%. Here i have seen a high power big station working from 180 to 300% of modulation. I've never ever seen something so wideband. Of course it was introducing a lot of noise on other channels... interesting exciter to handle that much signal.
 
DaveSt said:
When testing modulation you need to be very careful that the signal going into the modulation analyser is good. Low level (or excessive level) will make the modulation look very high because of noise/distortion. Likewise, high levels on nearby channels can also make the modulation look high. Anything that degrades the signal into the analyser will make the modulation appear high. The only certain way to measure deviation is to directly connect to the transmitters RF monitor port with a suitable attenuator/pad. Having said that, there are plenty of stations in the world that have crazy high level modulation.
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You're absolutely right. I checked it with my analyzer here, plus an SDR, a portable stereo, and two vehicle radios with a variety of antennas. I can hear signal bleedover on 100.1 on all of them. The station also has audio balance issues, often switching from mono to a louder left channel on its own. Definitely seems like they don't have a limiter or compressor to knock down the audio peaks.
 


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