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Firstly what is a spot? Well in it's simplest form it is a personal tracker. This is a small handheld, or belt worn, device that well acquire it's position from a the GPS satellites and relay this on command back via the Globalstar network. It can also provide an automated position fix every 10 minutes as well as having assistance and emergency messages available. To have a look at these things try the spot webpage.

Now as can be seen from the above we have two systems here that are involved in the reporting and display of positions so it seems natural that the two should get together. From an amateur's perspective here are a few of reasons why we did this:

  1. While most of the reports from mobiles are done on VHF it has the least amount of coverage of all of the possible options. A spot will provide almost global coverage.

  2. APRS messages can be submitted via HF however the radio you are using for this becomes dedicated to the task if you are looking to run the tracking full time. A spot frees up this radio needed to transmit the APRS data meaning you can operate HF mobile while still letting people know where you are.

  3. Size and power requirements for a spot are considerably less than those for a HF / Tiny Trak combination. This makes it a viable option for those hiking or just pedestrian mobile. A spot will run for days on a single set of batteries.

Operation is fairly straight forward and occurs in 2 steps.

We collect the data from the SPOT servers.

We submit it to the APRS network under the users callsign.

This system is still in the development stage however is showing a lot of promise. If you're an amateur, even a foundation call, and have a spot feel free to contact me with your email address and callsign and we'll add you to the list of units we're watching.

Here's a few we have running:

VK2JAP-13 This Gunter who may or may not be out and about.

VK2BOS-13 Steve with some occasional use.

VK2US-13 My own SPOT with some occasional use.

Recently 2 changes have been made to the core application. Firstly the system has now been se to handle multiple APRS servers and cycle between these two until a successful connection is made as well as in the event that an established connection to an APRS server is lost.

The other change was to send a message twice at 60 second intervals. It was noticed that a number of reports correctly captured from the SPOT site failed to appear on the network even though there was a connection to the server and it appears that the message had been send. This second send appears to have solved this. I’m investigating a more eloquent solution such as monitoring the second server to see if it sends out the report but this will take time.

Regards & 73's


Contact Peter VK2US


APRS <> Email/SMS



APRS Messages can be sent to EMail addresses and Mobile Phones.

Here's how you can do this using the SAMAIL server at VK3JFK-5;

A gateway server called SAMAIL supports a method of sending EMail and SMSs from APRS as outlined below. 

Note: all examples below are case Insensitive, either upper or lower case will work!

For example, you can simply send an email to me like this:

SAMAIL:VK3TBN@HOTMAIL.COM Hi Pete contact me on VK3RHF urgently!



SAMAIL will then send you an acknowledgement that it has sent the messages as an email to VK3TBN@HOTMAIL.COM





If you want to send me a number of emails you can set my Callsign up as a ShortKey set up with the server, this is to allow you to have up to a 3 letter abbreviation, rather than have to enter the whole call sign.

To set up your ShortKey list for me you would enter the following


Syntax is SAMAIL: (Shortkeycode) (Space) (Email Address)

ShortKeys are great for when you are sending messages with your Kenwood D7 or D700 radio.


Set up your own email address as a ShortKey like this, this will be useful later:

SAMAIL:me vk3???@????.com

Now go ahead and set up your other ShortKey addresses… Each short key entry will be acknowledged by SAMAIL

If you make a mistake, you can REMOVE a ShortKey entry by entering “R” after the short key, so if you want to correct you email address:


Syntax is SAMAIL: (ShortKeycode) (Space) (R)

And you should get an acknowledgement back that ME has been deleted. And now enter it in again as described above.

Ok so now you want to see what addresses LIST you have created? Make sure you have your address entered as a short key then enter “L” for a list of  all your short key entries. It will be sent to your email address:


Syntax is SAMAIL: (ShortKeycode) (Space) (L)

ShortKeys are Case Sensitive. ie ME is different to me

Ok this sets up the email but how do you get the SMS part working?

SMS Setup

Ok there are a few catches that I will tell you before doing this:

1.      It is one way ( well it can be two way but that’s for another time as there are strict provisions around that and it’s a little fiddley).

2.      The phone you nominate will be charged for each SMS sent to it from the forwarding email address

3.      Remember your commitment to 3rd party traffic undertakings within the rules of the Amateur service.

4.      There is a constraint, you can only send one line messages (67 total characters maximum), like any other APRS message.

If you are fine with the limitations, then lets move to the next step, to set up SMS forwarding.

They way to do it is to use a 3rd party email service provider for that.
I use
Hotmail (MSN) as I have found many ISPs and providers have recently removed the SMS facilities from their email systems.

You can also use Yahoo (I think) and they forward emails to mobile phones via SMS. Any provider that enables email forwarding to SMS is fine.

In general here is what you do, there are some variances form site to site, but its pretty much the same.

Set up an email account for the Mobile phone you want to send SMS’s to. Once this is done, then chose the option by the email provider to forward email messages to a mobile phone. It will ask you for a Mobile number and then it will SMS that mobile a keyword or number, which you have to email back to the provider to enable this function. Then in the email forwarding options, it will enable you to select which specific emails are forwarded to the mobile phone

Select emails from to be sent to the Mobile Don’t forget to enter this email address in your SAMAIL short key list as described above and send a test message via SAMAIL. You should find that you get the email, and it forwards to you SMS device (Phone).

For Hotmail:-

After you have loged in to your hotmail accout go to

To enable your 'HotMail Alerts' click on the SetUp button and follow the instructions.

Hint. If you use a hotmail account for every day email I'd recommend setting up a second hotmail account just for ARPS EMail SMS. Add the SAMAIL address to your contats and select 'New messages from my contact' in the 'Mobile Alerts for new messages' selection menu. This way you will only receive valid APRS Email SMSs and no SMS spam.

Yeah it's a bit of a mouth full but you only need to do it once.

Credit for this goes to VK3JFK who not only runs the APRS mail server, SAMAIL described here, but also thought of the idea to interface SMS to APRS messaging.

Sending an EMail into the APRS System

Sending an EMail to an APRS Station is a great way to get a short message to one of your Ham friends when your not near a radio.


  1. Email messages can be no more than one line messages (67 total characters maximum), like any other APRS message.

  2. You must be registered on the SAMAIL Server to send Emails to APRS Stations.

Server Registration

To register an EMail address for Emailing an APRS Station simply create a ShortKey for the EMail address as described above.

Sending a Message

Sending an Email message to the APRS Station is simple once you understand it.

Place the callsign-ssid of the destination station followed by a colon followed by the message text in the subject line. Place userid:ShortKey: in the message body where the ShortKey is the name associated with the senders email address.

Address the email TO:

In the SUBJECT type the call sign of the message recipient and the short message, separated by a ':'

The message must be less than 67 characters.

In the body of the message type 'userid:[ShortKey]:'




The SAMAIL server will only accept Plain Text messages.

If you send the server a Rich Text or HTML message it will ignore it and you will not receive an error.


Use lower case for the key word 'userid:'


Your message may take up to 10 or 15 minutes to reach it's destination due to RF conditions.


If your Email contains errors you will receive a reply email saying "Your message is undeliverable."


Author - Peter VK3TBN


APRS - QRZ Lookup


APRS - QRZ Lookup

SAQRZ Lookup allows you to lookup any Callsign on using an APRS message.

From your Kenwood D7, D700 or any APRS messaging software send an APRS message request to SAQRZ


Place the callsign of the station you want details on in the body of the message and send it To SAQRZ, summary details of the callsign you requested will be messaged back to you.



MSG: vk3jfk



If you want full details on a callsign, send an APRS message containing f [callsign] to SAQRZ and the server will send you several messages containing the Full details of the callsign you requested.



MSG: f vk3jfk




Site Alert


Site Alert Three ©
Warren Brown VK3BYD ©
April 2009
Project Overview
Site Alert is used to provide local site information from a remote UI-DIGI[A] APRS[B] Digipeater site via APRS Telemetry data.
The data is transmitted every 30 minutes and includes the average of four supply voltage readings, current in building temperature, number of PTT’s and the current mode of the Site Alert. The Parameter, Unit and Equation messages are sent once a day. (Further information on APRS Telemetry can be found in reference 1.)
Should the average voltage fall below a pre-programmed value Site Alert will turn off the Low Battery output until the average voltage reaches the upper pre-programmed value. This output can be used to control an external relay to remove power from the TNC and Radio. The battery alarm or the external alarm inputs will cause an APRS Item to the transmitted and an APRS Message sent
Site Alert uses an Atmel ATtiny2313 micro-controller, ADC0831 Analog to Digital converter, Dallas Semiconductor’s DS18S20 Temperature sensor and DS1307 Real Time Clock.
Feature Summary:
Software Version ‘FE’ (Dec 2008)
  • Eqns, Parm & Unit messages are sent at 0900 Site alert time (once a day)
  • All Alarm Message from Site Alert have messaging numbering
  • The Low Battery Alarm is only transmitted ~four times then Site Alert will “turn off” the Low Battery output.
  • An ‘OK’ message (only) will be sent when the voltage becomes high enough for Site Alert to “turn on” the Low Battery Output.
  • All the Alarm Messages and Alarm Items contain the last Voltage.
  • The Led will remain on whilst Site Alert is busy otherwise it flashes 9 second on/off.
  • Alarm input 1 has a lockout period of 9 minutes. That is once an alarm has been received on Input 1 no further alarms on that input will be recognised until after 9 minutes has passed.
Site Alert3 Plus will add the following features
  • Over Temperature alarming added to in built temperature sensor
  • Second A-D port with Low voltage alarming
  • Option for second temperature sensor with Over Temperature alarm
  •  Second relay output whose operation is selectable for an alarm on Input 1, an Over temperature on the main sensor , or a Low voltage on second A-D
  • A change in alarm status message is only sent four times. ( The Alarm Item is still sent until all alarms have cleared)
  • An enhanced user interface
Voltage readings will only be accurate for voltages above 8.1 Volts or below 19.9 (25.5 for SA3+) Volts.
Temperature readings are only accurate from 0 to + 85 Degrees C
Site Alert Local Commands must be correctly formatted, as there is NO checking for validity of the entries.
The Traffic counter will only count accurately to 511 in any 30-minute period.
Site Alert is not a full multi tasking device. However it is more than capable of coping with the day to day running of a remote radio site.
Sample Data
Do Not use this device for any application where human life is at risk or property damage may occur. The developer takes no responsibility wholly or implied for the use or performance of this product and offers no warranty of any type on this product.
Anybody who is interested in this project can contact me on e-mail at “vk3byd ‘at’” .
1)       APRS Protocol Reference Version 1.01

[A] UI-DIGI is copyright of Marco Savegnago IW3FQG
[B] APRS is copyright of Bob Bruninga WB4APR


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