Being a ham radio operator, I posed a query to Google (AU) “how long can you transmit on AM”. For anyone interested, a ham transmitter cannot transmit continuously, as our conversations tend to be short “overs”, back and forth, allowing the radio to cool down in-between the overs. AM (amplitude modulation) heats up “the finals” (the hard-working end of the transmitter) more than SSB (single sideband), which is the more common form of communication we use on HF (high frequency, also known as shortwave). In radio broadcasting, the transmitter is working continuously.
Here is the result:
The background to this was a rather naive question posed in an amateur radio group on Facebook by someone who would like to broadcast on shortwave. He could not find any solution at ACMA, the government site that manages the radio spectrum in Australia.
I tried a more explicit term “AM transmitter duty cycle“, but barely one result is relevant. (Expanding AM to Amplitude Modulation made it worse). Trying the more collquial ham language “rig overheats duty cycle” (as hams are likely to discuss such topics, whereas broadcast engineers already know their stuff) brought up oil rig hydraulics. Mentioning my rig model helped, but not many useful results: “ft-991a overheats duty cycle“. The one that worked in the end was “ham radio overheats duty cycle“, with most results being relevant. So I needed to know most of the solution to frame the correct query! Up to this point, I got Google onto the correct topic, but not about broadcasting equipment. Ham radios are not built to transmit for hours without a break. The old valve (tube)-based models were better for longer transmisions; however, broadcast transmitters need significant cooling solutions, such as water cooling.
So why does Google fail to know much about this topic? It was put to me that ham radio is a rather obscure niche within geekdom, which is a niche to begin with. Cool people do not venture in these parts. To be honest, not many hams have used AM since SSB began to appear on ham radios in the 1970s. I have not used it, even though the mode exists on my Yaesu FT-991A transceiver. Although “ACMA” is probably as well-known as “Ofcom” or “FCC” are known, I could not find its home page on the first page of Google – but that might be the lack of SEO on ACMA’s part? That naive user trying to learn about shortwave broadcasting would have no hope of finding the answer.
That disappoints me — about Google. Surely its crawlers can find numerous ham radio websites outside of Facebook and learn that transmitters have duty cycles and “transmission” is not restricted to a disease? I did not see results about car transmissions either, so it seems that the year-long pandemic has overwhelmed Google’s AI into thinking there is nothing else on people’s minds.
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Are Other Search Engines Any Better?
To be fair, I checked the query in Bing: How long can you transmit on AM? In the top 50 results, barely a couple were about radio and almost all the others were about Covid-19, colds and other diseases. DuckDuckGo was just as bad. WolfRamAlpha first thought Transmit is a software product, but allowed me to change the definition to a Word, after which it spewed out a lot of definitions.
Sometimes, Ask a Human Instead
So my original query, “How long can you transmit on AM?” would be perfectly understood by a fellow ham, or a broadcast engineer, and a useful conversation with some confirmation questions would rapidly lead to the answer. Sometimes, there are answers outside search engines.