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From this poster, http://info.tek.com/AM-RSA306-Spectrum-Poster.html, enter image description here

it indicates that a band around 433 MHz is globally-accepted for use as an amateur band.

Can this same band be used for industrial-scientific-medical (ISM) purposes?


Pertaining to North America some more info can be found here.

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    $\begingroup$ Please do not put "EDIT" sections in your posts. Instead, fully incorporate the new text as if it was always there. $\endgroup$ – Kevin Reid AG6YO Mar 5 '18 at 3:21
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    $\begingroup$ Is there any reason for this rule? I was actually trying to clearly indicate to others that the extra piece of info was not always there. I also couldn't find any such rule from the FAQ (meta.stackexchange.com/questions/7931/…), nor from a post (meta.stackexchange.com/questions/11474/…). However if such a rule exists, I'll comply with it for the future. $\endgroup$ – plu Mar 6 '18 at 22:38
  • $\begingroup$ meta.stackexchange.com/a/127655/159388 "For future readers, posts need to be standalone, without any history. These sites are not forums, but intend to be libraries of canonical, high-quality, questions and answers. Future readers are not helped by seeing all kind of history." And edit history is automatically recorded for reference if there is any confusion. $\endgroup$ – Kevin Reid AG6YO Mar 6 '18 at 22:53
  • $\begingroup$ @plu It's OK put the EDIT in as you have done temporarily. :-) $\endgroup$ – Mike Waters Mar 6 '18 at 22:56
  • $\begingroup$ Okay, after reading that post, I agree; "EDIT" tag removed. $\endgroup$ – plu Mar 7 '18 at 4:53
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ISM (Industrial, Scientific, Medical) is a pretty broad umbrella. It is possible for devices to send data automatically on the ham 70cm band that you're talking about, but transmissions have to conform to the law. The law varies somewhat from country to country, but there are certain rules in common:

  • The sender must have a ham license
  • The transmissions must be identified by call sign periodically (every 10 minutes in the US)
  • Transmissions for pecuniary interest (for profitable or business purposes) are not allowed
  • Encrypted transmissions aren't allowed
  • Cursing isn't allowed
  • International third-party traffic (messages on behalf of someone in another country) are not allowed between some countries

With all those rules, there isn't much legal use of ham bands as an ISM-band alternative.

EDIT: it turns out that some countries in ITU region 1 (Europe, Africa, the Middle East west of the Persian Gulf including Iraq, the former Soviet Union, and Mongolia) do have a small ISM band allocation from 433.05 MHz to 434.79 MHz, according to Wikipedia, which would seem to overlap the amateur radio 70cm band. In countries that do have that ISM band allocation, then the answer to the question is yes: that narrow part of the ham band can be used for ISM purposes according to the laws that govern ISM operation. So those ISM band users wouldn't need to identify with a call sign, but they would need to abide by ISM power limits and other rules.

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    $\begingroup$ Sender must have ham license. What? The whole point of ISM is that it's not ham radio and doesn't require individual licrnse. $\endgroup$ – AndrejaKo Jan 20 '17 at 18:46
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There is a very narrow sliver of bandwidth at 433MHz that is designated as an ISM band that overlaps the ham band, however the power limitations are quite severe, as are antenna and bandwidth limitations. Nearly all off-the-shelf ham gear would be out of specs for ISM use, and as such would have to operate under Part 97. Depending on what you want to do, it may well be legal and possible to use ham equipment to perform the same tasks, but not under the same rules.

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Since I cannot post a comment - ISM and ham radio - apples and oranges. They both have their rules and frequencies. Just because there is ISM in 433 MHz we do not need to know that cursing is not allowed on ham bands.

ISM has regulations, licensing is not one of them!

Your mileage will vary , from region to region, from country to country, that about all.

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There is (In many countries) a small slice of the 70cms band that is allowed to be used for LPD use (The name varies), basically low power, low duty cycle things like door openers, car alarm keyfobs, smart meters, and other similar applications in the (usually 10mW) power class and at low duty cycle. This is NOT ISM in the 13.6MHz, or 2.4GHz sense, the devices need type approval.

These devices must accept interference from the other band users, who can be running 40+dB more power, and while nobody tries to communicate on 433.05 (The QRM makes it pretty hopeless) interference with LPD systems on that frequency is not uncommon, mostly because they tend to use rather heavily 'cost optimised' receivers that do not react well to a signal 50dB stronger only a few KHz away.

A 70cm repeater next to a used car lot is a thing of beauty and joy.

Basically many countries allow the use of very low power things near 433MHz without a license, but the devices must have some form of type approval and must accept interference from licensed users of the band, that allocation is now so over used that where available you are smarter to use the 868MHz allocation instead.

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In simple terms, there are some devices that simply cannot help but generate RF interference when they are being used. So, it was long ago agreed that this RFI is legal, provided that they only radiate on certain frequencies.

The Industrial, Scientific and Medical ("ISM") frequency bands are reserved for the use of such high-power radio frequency (RF) energy radiated as a consequence of industrial, scientific and medical purposes other than radio communications such as amateur radio.

An amateur or other radio communications license is not needed by operators of ISM equipment.

Some of these devices include RF induction heating and welding machines, microwave ovens, and some medical equipment. The RF emissions of these devices --which in some cases can be transmitted very long distances-- can completely disrupt legal radio communications using the same frequency. Therefore, these ISM devices were limited to certain bands of frequencies by international treaties.

Some of the ISM bands overlap amateur radio frequencies and CB channels. Regardless of that, communications operating in these bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation.

https://www.techopedia.com/definition/27785/industrial-scientific-and-medical-radio-band-ism-band

https://en.m.wikipedia.org/wiki/ISM_band

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  • $\begingroup$ Many years ago (around 1970) I thought I heard that the three ISM bands below 30 MHz had no power or ERP limit. I couldn't find any information today, does anyone recall anything about that? In theory (so we thought) we could legally build a large transmitter and maybe even communicate there without a license. Just curious. $\endgroup$ – Mike Waters Jan 26 '17 at 17:27

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