dhays
Guru
- Joined
- May 26, 2015
- Messages
- 9,435
- Location
- Gig Harbor, WA
- Vessel Name
- Kinship
- Vessel Make
- 2010 North Pacific 43
I blame SHASHA III.
Vic mentioned in a thread about SPOT and Delorme Inreach that he was going to install a Dual band Ham radio with internal gps and integrated TNC (Terminal Node Controller?). He explained that with that equipment he can update his position for others to follow on the the aprs.fi website and it has the capability to send and receive text messages from outside the Ham network.
I didn't (and don't) understand any of that. However, I have been using a SPOT on the boat. While the SPOT is a nifty tool, the $150/yr subscription is annoying and it will do little but provide location information and contact emergency services in case of an emergency. I thought I would try and figure out what Vic was talking about.
So, since I know nothing about amateur radio (other than it is a bunch of old guys who were geeks before "geeks" was even a thing) I tried to do a little checking. This is what I think I have learned so far. I would love it if those of you who actually know this stuff, and help me in my understanding.
Dual Band: In this case I believe this means VHF and UHF. Here is where terminology confuses me but another way to think of this band range is the 2M and 70CM bands. Not sure if these radios will transmit and receive on the marine VHF bands even though the receivers cover the 156-157MHz frequencies.
GPS: yeah, even I know what is. Like AIS, the radio will take positional information from its gps and include that information in the packets that the radio sends out.
APRS: Automatic Packet Reporting System. This is where my head starts to hurt. As near as I can tell, the APRS radios simply send out data packets which contain a whole host of possible digital information. This can be gps positions, weather, object icons, and text information. These packets are sent out on 144.390 MHz in the US and Canada.
TNC: I really have no idea what this is other than I think it translates the packet received by the receiver to a format that can be read by a computer. In this way it can be output to a computer display. The reverse would be true as well, convert digital data into a format that the radio can send as packet.
Not sure if I understand all the pieces but the thing that intrigues me is that a couple manufacturers, such as Kenwood, have put all those pieces together in a single unit.
I am not exactly sure how APRS works, but here is my very simplified understanding, again please help me get this right. An APRS radio will send out a data packet on the 144.390 MHz frequency. This data packet isn't directed at any receiving station but just broadcast generally. This packet is picked up by other APRS radio stations that are setup as repeaters. These stations add their own call sign to the packet and rebroadcast it. There is a limit to the number of times a packet will be broadcast and this is determined by coding contained within the packet that direction that behavior but that is all beyond me.
Eventually, the packet will be picked by a station that is an internet gateway. These stations take the data from the packet and send it off to APRS servers that aggregate and disseminate all this information to other servers around the world.
So how does that help me on a boat?
Vessel Tracking: A APRS capable radio could send out a packet with my call sign, vessel name and information, as well as position and heading. This works much like AIS does. The packet is repeated until it is added to the information on the servers. Friends and family can then see where I am by simply looking on the website. This is much like SPOT does for me now but without an annual fee.
Messaging: Here is where it gets really cool. I am often out of cell range. It is possible to create a text or email message addressed to a cell phone and that gets included in a packet. That text is broadcast with the packet and sent to the internet gateway. There are servers that magically send those messages as emails or as an email text message to the persons cell carrier. This would be a huge boon to my wife and I as we still like to be able to keep with touch with family and me with work.
So, what have I got wrong?
What have I gotten right?
What are the practical problems or advantages to doing something like this?
How easy/difficult is it to install a ham radio on a boat that already has two VHF radios, GPS antenna, radar, and two VHF antennas?
Vic mentioned in a thread about SPOT and Delorme Inreach that he was going to install a Dual band Ham radio with internal gps and integrated TNC (Terminal Node Controller?). He explained that with that equipment he can update his position for others to follow on the the aprs.fi website and it has the capability to send and receive text messages from outside the Ham network.
I didn't (and don't) understand any of that. However, I have been using a SPOT on the boat. While the SPOT is a nifty tool, the $150/yr subscription is annoying and it will do little but provide location information and contact emergency services in case of an emergency. I thought I would try and figure out what Vic was talking about.
So, since I know nothing about amateur radio (other than it is a bunch of old guys who were geeks before "geeks" was even a thing) I tried to do a little checking. This is what I think I have learned so far. I would love it if those of you who actually know this stuff, and help me in my understanding.
Dual Band: In this case I believe this means VHF and UHF. Here is where terminology confuses me but another way to think of this band range is the 2M and 70CM bands. Not sure if these radios will transmit and receive on the marine VHF bands even though the receivers cover the 156-157MHz frequencies.
GPS: yeah, even I know what is. Like AIS, the radio will take positional information from its gps and include that information in the packets that the radio sends out.
APRS: Automatic Packet Reporting System. This is where my head starts to hurt. As near as I can tell, the APRS radios simply send out data packets which contain a whole host of possible digital information. This can be gps positions, weather, object icons, and text information. These packets are sent out on 144.390 MHz in the US and Canada.
TNC: I really have no idea what this is other than I think it translates the packet received by the receiver to a format that can be read by a computer. In this way it can be output to a computer display. The reverse would be true as well, convert digital data into a format that the radio can send as packet.
Not sure if I understand all the pieces but the thing that intrigues me is that a couple manufacturers, such as Kenwood, have put all those pieces together in a single unit.
I am not exactly sure how APRS works, but here is my very simplified understanding, again please help me get this right. An APRS radio will send out a data packet on the 144.390 MHz frequency. This data packet isn't directed at any receiving station but just broadcast generally. This packet is picked up by other APRS radio stations that are setup as repeaters. These stations add their own call sign to the packet and rebroadcast it. There is a limit to the number of times a packet will be broadcast and this is determined by coding contained within the packet that direction that behavior but that is all beyond me.
Eventually, the packet will be picked by a station that is an internet gateway. These stations take the data from the packet and send it off to APRS servers that aggregate and disseminate all this information to other servers around the world.
So how does that help me on a boat?
Vessel Tracking: A APRS capable radio could send out a packet with my call sign, vessel name and information, as well as position and heading. This works much like AIS does. The packet is repeated until it is added to the information on the servers. Friends and family can then see where I am by simply looking on the website. This is much like SPOT does for me now but without an annual fee.
Messaging: Here is where it gets really cool. I am often out of cell range. It is possible to create a text or email message addressed to a cell phone and that gets included in a packet. That text is broadcast with the packet and sent to the internet gateway. There are servers that magically send those messages as emails or as an email text message to the persons cell carrier. This would be a huge boon to my wife and I as we still like to be able to keep with touch with family and me with work.
So, what have I got wrong?
What have I gotten right?
What are the practical problems or advantages to doing something like this?
How easy/difficult is it to install a ham radio on a boat that already has two VHF radios, GPS antenna, radar, and two VHF antennas?