I know that 144-148 and 156-157 mhz ranges are in use, and various fire/ems/police, but outside of that, I see a lot of earth-to-space, weather stuff and space research allotments (talking about Canada here). Outside of using a scanner, is there any way to know if the metrology / space / satellite allotments are in actual use in a particular area?
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1What do you mean by "in use"? Someone is transmitting on that frequency, right now? Someone is monitoring it, right now? It's allocated to someone? – Phil Frost - W8II Jan 07 '21 at 14:21
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1Hi Peggy, and welcome to ham.stackexchange.com! – rclocher3 Jan 08 '21 at 01:09
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1@PhilFrost-W8II I'd guess that she looked at a frequency allocation chart like [this one](https://www.ntia.doc.gov/files/ntia/publications/january_2016_spectrum_wall_chart.pdf), but for Canada. – rclocher3 Jan 08 '21 at 01:15
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In my experience the parts allocated to PMR are extremely busy, it's the most popular band for walkie talkies and car radios, best compromise between antenna length (60 MHz is quite bulky) and path loss + diffraction (450 MHz is not as nice).
But busy doesn't mean 0.5 Erlang, because analog FM and Push To Talk are so inefficient.
Without actually analysing the traffic yourself, you could:
- look for research papers that do just that, in a similar city
- try to find the allocations from the spectrum management authority. If they're not already public information, It's possible you could retrieve the entire list of allocations, perhaps anonymised, with an FOIA request or similar. Bear in mind that allocated will just mean someone is paying for their spectrum license, not necessarily using it.
tomnexus
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I'm wondering what sort of space, satellite or weather / meteorology communications might be happening (or might have happened in the past if not happening now) if those are the uses identified in the various tables for these frequencies? – Peggy Schafer Jan 08 '21 at 00:56
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1I'm under the vague impression, not supported by any solid facts, that many allocations are agreed to at international conferences and then written into treaties, and then written into law by legislatures in support of the treaties, whether or not such activity actually takes place in a given country or not. Just a guess. – rclocher3 Jan 08 '21 at 01:24
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I'm pretty sure there's weather fax downlinks from satellites in the 137MHz area, but I haven't found a list of specific frequencies. – Duston Jan 08 '21 at 14:58
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@PeggySchafer You didn't say, but if you are interested in listening there then a tall, properly installed metal tower with a suitable, rotatable antenna on top might pick up many more signals than a typical antenna that's mounted on a scanner. – Mike Waters Jan 08 '21 at 21:58
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Canadian frequency spectrum allocations can be found here: http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf10759.html#t2 Hope this helps.
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Yes, seeing how various sub-bands are allocated does not tell me if those frequencies are or ever have been in regular use for those purposes. I was thinking that it should be "common knowledge" among radio amateurs how the spectrum nearby the amateur bands are used, or perhaps I'm over-estimating their knowledge or familiarity with radio communications in general. – Peggy Schafer Jan 08 '21 at 14:20
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@PeggySchafer below 1GHz, it's a safe bet that if it's allocated, people are using it, a lot :) – hobbs - KC2G Jan 08 '21 at 19:11
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@PeggySchafer *Some* amateurs are likely familiar with and interested in non-amateur In my case, in my 44 years of being licensed, I *usually* wasnt. But I tend to agree with hobbs-KC2G: even if you can't hear anything with your existing antenna, perhaps there are radio transmissions just out of your reception range. – Mike Waters Jan 08 '21 at 21:50