David3D
Newbie
Hey guys,
Brand new to the forum and the colosal deep dive that radio communication has taken me on. With that in mind, my questions or understanding may seem stupid or downright ignorant of rules and regulations at best, or the laws of physics at worst, so my apologies in advance.
I'm designing a tracker designed to use GPS, GSM and the SigFox/IOT network to keep expensive equipment locatable in the event of said equipment being stolen. Could I buy an off the shelf product? Probably. Would that be nearly as fun? Probably not. Anyway, I want to implement a radio transmitter capable of transmitting a pulse to a directional or omni-directional antenna in the event I have to turn the recovery of the equipment in to a fox hunt if it goes missing. The questions I have are regarding power output, antenna types/gain and optimal performance for certain situations.
In my case a battery operated device which would otherwise be dormant is awoken with a text message and the beacon starts transmitting. But I'm anticipating the likes of garages, shipping containers and the like getting in the way. Shipping containers are of particular concern.
Question one: "What would be the optimal frequency to consider if I wanted the beacon to penetrate solid objects to ensure a strong signal in urban environments?"
From what I understand, the lower the frequency the better penetrative power it has due to it's longer wave. I'm not against licensing a particular part of the spectrum to get the best range capabilites and penatritive properties possible. It would be nice if that could be avoided, but needs must.
Question two: "At what point does a beacon's power become too powerful and the correct size antenna/gain become more important for my particular usecase?"
If my limited research has taught me anything, it's that I can make the beacon so powerful, it's almost impossible to narrow down exaclty where it is, because directional antenna don't work nearly as well when close to the source. Is this true?
Question three: "Is the ISM band too (high frequency wise) to be able to transmit effectively over long distances?"
I know this question is so dependant on so many variables that it's almost impossible to answer. But I guess what I'm asking is if anything in the ISM band is remotely useful for my usecase.
Question four: "What specifically is the difference between say a $160 - $300 Marshall transmitter beacon and a $5.00 ebay special when both communicate on the 433MHz band at 500mw?"
There are YouTube videos of people using LoRA modules to communicate 2 or more kilometers away. This is more than enough range in terms of what I'm looking for, but they are using their equipment line of sight. I'm certainly not doing that. So would that make this technology irrelivent for me specifically? Or would I just need an order of magnitude more power to get the same range.
Question five: "Would implementing multiple beacons that transmit at different frequencies be the solution to my problem?"
Would transmitting at variable power limits across different areas of the spectrum be a catch all to make sure the device can be contactable in a broader range of scenarios?
Sorry if any of these questions come off a bit silly. I'm trying to get a better understanding of the ISM band, what constitutes high power or not enough in the kind of scenarios not a lot of people utilise the band for. Maybe I'm asking too much of the technology, I don't know.
I was thinking, should I get a rough idea as to where the tracker was via the mobile network, but no GPS location, a drone with a suitable antenna array attached to the bottom would be my best way to achieve a better line of sight. But those rules and regulations are for a different forum, haha.
Very much looking forward to the discussion.
Cheers!
David
Brand new to the forum and the colosal deep dive that radio communication has taken me on. With that in mind, my questions or understanding may seem stupid or downright ignorant of rules and regulations at best, or the laws of physics at worst, so my apologies in advance.
I'm designing a tracker designed to use GPS, GSM and the SigFox/IOT network to keep expensive equipment locatable in the event of said equipment being stolen. Could I buy an off the shelf product? Probably. Would that be nearly as fun? Probably not. Anyway, I want to implement a radio transmitter capable of transmitting a pulse to a directional or omni-directional antenna in the event I have to turn the recovery of the equipment in to a fox hunt if it goes missing. The questions I have are regarding power output, antenna types/gain and optimal performance for certain situations.
In my case a battery operated device which would otherwise be dormant is awoken with a text message and the beacon starts transmitting. But I'm anticipating the likes of garages, shipping containers and the like getting in the way. Shipping containers are of particular concern.
Question one: "What would be the optimal frequency to consider if I wanted the beacon to penetrate solid objects to ensure a strong signal in urban environments?"
From what I understand, the lower the frequency the better penetrative power it has due to it's longer wave. I'm not against licensing a particular part of the spectrum to get the best range capabilites and penatritive properties possible. It would be nice if that could be avoided, but needs must.
Question two: "At what point does a beacon's power become too powerful and the correct size antenna/gain become more important for my particular usecase?"
If my limited research has taught me anything, it's that I can make the beacon so powerful, it's almost impossible to narrow down exaclty where it is, because directional antenna don't work nearly as well when close to the source. Is this true?
Question three: "Is the ISM band too (high frequency wise) to be able to transmit effectively over long distances?"
I know this question is so dependant on so many variables that it's almost impossible to answer. But I guess what I'm asking is if anything in the ISM band is remotely useful for my usecase.
Question four: "What specifically is the difference between say a $160 - $300 Marshall transmitter beacon and a $5.00 ebay special when both communicate on the 433MHz band at 500mw?"
There are YouTube videos of people using LoRA modules to communicate 2 or more kilometers away. This is more than enough range in terms of what I'm looking for, but they are using their equipment line of sight. I'm certainly not doing that. So would that make this technology irrelivent for me specifically? Or would I just need an order of magnitude more power to get the same range.
Question five: "Would implementing multiple beacons that transmit at different frequencies be the solution to my problem?"
Would transmitting at variable power limits across different areas of the spectrum be a catch all to make sure the device can be contactable in a broader range of scenarios?
Sorry if any of these questions come off a bit silly. I'm trying to get a better understanding of the ISM band, what constitutes high power or not enough in the kind of scenarios not a lot of people utilise the band for. Maybe I'm asking too much of the technology, I don't know.
I was thinking, should I get a rough idea as to where the tracker was via the mobile network, but no GPS location, a drone with a suitable antenna array attached to the bottom would be my best way to achieve a better line of sight. But those rules and regulations are for a different forum, haha.
Very much looking forward to the discussion.
Cheers!
David