Salt Spring Island Amateur Radio Society

April 16, 2024 15:23 UTC

2014/09/22

These notes should be considered very much a "work in progress" and just a supplement to the manual. It doesn't replace it. Hopefully it can be used as a "quick start guide" to encourage people to pick the radio up and get used to it. It has many features, but if you use it for a few days, you should be able to get familiar with most of them.

DESCRIPTION

The D72 is a dual band radio (VHF / UHF) capable of outputting 5W, .5W or .05W. Power can be set independently on the A and B bands. What sets the D72 apart from most other radios is that it has APRS capabilities with a TNC and GPS receiver built right into the radio.

APRS is Automatic Packet Reporting System. As implemented in the D72, it is capable of beaconing your position, heading, speed, altitude and even the voice frequency that you are listening to, as well as sending and receiving APRS messages.

The TNC can be used in either the A or B side. This is set in a menu, but more on this later. The TNC can be used for APRS (stand-alone or connected to a computer running an APRS client like UI-View) or for packet radio with it connected to a computer running a terminal program or a program like Winlink Express.

If you are going to program the radio from a computer, install the virtual com port driver before connecting the radio. It can be downloaded from the Kenwood website.

The programming software is available on Kenwood's download page.

A standard USB to mini-B cable is used to connect to the USB port on the right side of the radio, but the supplied cable has a ferrite bead on it.

The radio should be turned OFF before connecting the charger. Two LEDs on the top of the radio will be lit while charging. Being a Lithium battery, you would think it would be a smart charger, but the instructions are to disconnect the charger after the LEDs turn off.

If you ever have to remove the battery, flip back the clip on the bottom of the battery. Then PUSH in on the tab behind the clip and lift the battery up away from the radio and then slide it out. Do not allow the terminals to become shorted.

An "in depth" manual for the radio is available from Kenwood's website.

Helpful videos about using the TH-D72A...
www.youtube.com/watch?v=r4IuACLGTqs

Review of several radios including the D72A...
http://changelog.complete.org/archives/7501-review-amateur-radio-handhelds-hts-aprs-and-battery-tuning-tips

THE BASICS...

To turn the radio on, press the "power" button below the display / above the joystick.

The CALL / MR / VFO buttons (D, C and B) are on the lower right side of the keypad.

CALL

The call channel is just a special channel with "one button" access, using the D key on the keypad. While currently set to 146.520 MHz which is the national 2 metre calling frequency, other good choices would be 147.320+ or 146.460, but so would 146.520 MHz. When the call channel is selected, the letter C will be displayed where you would otherwise see a channel number. See elsewhere for programming the CALL frequency.

MR

MR is of course "memory recall" mode. When in memory mode, a channel number will be shown by the frequency. The A/B button which can be used for toggling back and forth between VFO A and B (or two memory channels) is above the middle of the keypad. Press DUAL (the zero key on the keypad) to toggle between single and dual receive. If you want to use the D72 for APRS and for voice at the same time, dual receive should be enabled.

Whether in VFO or MR mode, the frequency or channel can be changed by using the joystick (up / down) or by rotating the select knob on the top of the radio.

While in VFO mode, press the ENTer (# key) button first to directly enter a frequency from the keypad.

NOTE... with the radio set up for APRS use, it can be "locked" so that it will always be locked on the APRS frequency. If you try and change the channel or frequency when it is set like this, the display will indicate "APRS Lock". This is actually a good thing if you intend to use the radio for APRS. With it locked, you can't accidentally change it from the normal APRS frequency.

There are two concentric knobs on the top right corner of the radio. The centre one is the "select" knob and the lower/outer knob is the volume control. Given that the rest of the radio is menu driven, it would have been nice if the volume was the same way. It is very easy to accidentally turn the volume up or down as there is little friction in the volume control. To check the volume when there isn't a signal present, press the MONITOR button (lower button, left side of radio) and adjust the volume control. The monitor button just opens the squelch.

The PTT is in the usual location near the top left side of the radio. The lamp (backlight) button is below it and the lower button is the monitor button which opens the squelch. The lamp can be locked on by pressing the function button (see below) followed by the LAMP button.

The menu button is on the top right corner of the D72. The function button is immediately below it.

Keypad Lock... if the keypad is locked, you can't change any settings. If it is locked, there is a "key" symbol near the top right corner of the display. Press and hold the Funciton button (the A key near the top right corner) to lock or unlockk the keypad.

As mentioned above, there are three settings for output power. Press Function-Menu (low) to change the power setting. Look for H, L or EL at the top left corner of the display to see the current setting... high, low or extra low.

Generally speaking, high power should be used for APRS for better reliability. Transmissions are very brief, so the power setting on APRS isn't a large factor in how long the battery will last as it is for voice transmissions. The radio while on receive and the TNC and GPS receiver are bigger users of the battery than APRS transmissions because they are so short. Voice transmissions are very often be the largest consumer of the battery. Performance will be better with an antenna with a bit more gain than the supplied rubber duck. One of the super flexible dual band 16" whips will make a huge difference.

APRS

APRS can be used on the A or B "band" but traditionally A (top of display on the D72) is used for APRS and B is used for voice.

In North America, 144.390 MHz is the main APRS frequency.

Packet

The radio can also be used for packet radio. Turn the GPS off with function-GPS (the 1 key) and then toggle the TNC from APRS12 to PACKET12 with the TNC button (the 2 key). Connect the supplied USB cable to the radio. NOTE... the driver should be installed before connecting the cable to a computer. In Winlink Express, open a Packet P2P (peer to peer) session and go to SETUP. If it isn't already set to D72/A Band, set it to that. Set the com port. If you don't know which com port it is, look in the Device Manager. The "baud" rate should be 9600 bps. To put it back to APRS, turn off the tadio and remove the cable. Power it back on and toggle the TNC back to APRS12 and turn on the GPS receiver.

Battery Save

For the most reliability, battery save should be turned OFF for APRS and for Packet. However, turning it on will stretch out the battery life while sometimes causing you to miss the odd beacon or causing a few more retries for APRS messages or packet reception. Setting it to something less than 1 second might be a reasonable compromise if you want to try and stretch the operating time out a bit.

VOICE ALERT

They are also programmed with a 100 Hz tone on that channel so they can be used vor "voice alert" on the APRS frequency. This feature just means that the squelch will open and you will hear a burst of data on the speaker if you hear an APRS beacon from another station using voice alert. This is a feature that is probably more useful for mobile stations in the middle of nowhere. If a 100 Hz tone is detected, the squelch will open and you will hear a burst of data. The idea is to then make a quick voice call on 144.390 MHz and make contact and then move off to a simplex or repeater frequency. Voice Alert can be toggled off/on in Function 7. Press the function button and either use the joystick to move up/down or just press 7 on the keypad. Then press enter on the joystick, and then up/down to change the setting to either off, receive only, or on. The tone is set (normally 100 Hz) with F-8. Voice Alert must be ON before the tone frequency can be changed.

GPS

While a fixed position can be entered, the internal GPS can be used to obtain the position.

To get it beaconing on APRS, make sure the TNC is turned on and in APRS mode (as opposed to OFF or in Packet mode), and the GPS must be turned on (unless a fixed position is entered) and beaconing must be enabled.

The TNC is toggled between OFF, APRS and Packet with the #2 key on the keypad, labled TNC. As you step through the settings, they are OFF, APRS and Packet. It should be set for APRS12 for normal 1200 bps APRS.

The internal GPS is togged on/off with F-1. Press the function key and 1 on the keypad. When it is ON, you should see iGPS in the top right corner. When the GPS has a lock (a position) it will be flashing.

Finally, beaconing must be enabled. This is done with the BCON button which is 6 on the keypad. You must see BCON on the display or will not beacon. You can still receive as long as the TNC is in APRS12 mode. You can force a beacon by toggling BCON OFF and then back ON again.

With it actually beaconing, there are two other matters to deal with... the beacon rate and the path. The beacon rate can be at a fixed rate (e.g. every 5 minutes) or it can have SmartBeaconing enabled. With SmartBeaconing there is a slow rate and a fast rate, and a corresponding slow speed and a fast speed. Traveling below the slow speed, it will beacon at the slow rate. Traveling at or above the fast speed, it will beacon at the fast rate. In between the two speeds, the beacon rate is adjusted accordingly. It also does "corner pegging" which forces it to beacon when you turn a corner.

If you are going to be walking, I would suggest setting the slow speed to between 3 and 5 kmh and the fast speed to 30 kph. This is well above a walking speed, but it would give you a variable beacon rate and still be acceptable for a short time on the road. Away from Salt Spring where there are highways where you could travel for hours at 80 kph, the fast speed should be set to 80 kph.

I would not recommend setting the slow speed less than 5 kph. If the D72 was indoors, and less GPS satellites within sight, it could easily make it look like you were wandering around forcing it to beacon at a higher rate unnecessarily. On the other hand if you are outdoors with a good view of the sky and actually moving, it wouldn't hurt to set it to 3 kph.

To understand the path, you need to understand a bit about APRS digipeaters. They are like repeaters, but unlike voice repeaters which have the audio coupled from a receiver to a transmitter, there is just a transceiver on a single frequency. It is connected to a TNC or terminal node controller. TNCs were developed for packet radio long before APRS came along. A TNC is kind of like a modem used on a telephone line. The "mo" is from modulator and "dem" is from demodulator. It just sends and receives tones. A TNC is a bit more than just a modem in that it has some intelligence built into it. Without going into it too deeply, a TNC set up as a digipeater decodes received tones and if certain requirements are met, it causes the tones to be retransmitted. It is a store and forward system. To over-simply digipeaters, you will usually want a one or two hop path. In the D72, it will be set to use WIDE1-1 if you enable a one hop path. The last "1" indicates that a one hop path is requested. If you enable a two hop path, it will use WIDE1-1,WIDE2-1. Paths are used sequentially. The WIDE1-1 is acted upon first. Once that is used, one hop is obtained from the WIDE2-1. The path is selected in MENU - APRS - PacketPath. Hit OK to enter the menu, leave New-N enabled (I'll explain this another time) and scroll down to TOTAL HOPS. Hit OK and use the joystick up/down to select either one or two hops. It is rare that more than two hops would be needed.

It is not necessary to use any digi path at all. It is possible for two D72s to be within earshot of each other and communicate back and forth without the help of a digi. However, Salt Spring Island is quite hilly, and if the two radios aren't close to each other, there's a good chance that they couldn't talk to each other without the help of a digipeater. Another than that using a digi path will do is help you get to an iGate. An iGate takes everything that it hears and sends it to the APRS-IS... the APRS Internet System. This is a network of many servers around the world. They all talk to each other. It is possible someone very distant from your location to see your position and even send and receive messages to you. This does of course require that the Internet be operational. While much can be done because the APRS-IS exists, you can't count on it being there during a massive disaster. That doesn't mean that you can't take advantage of it. It just means that you should be aware of a limitation if anything major happened to cause the Internet to disappear.

The D72 is capable of including a voice frequency in your beacons. This is toggled in MENU - QSY(FREQ). It is set to include the voice frequency in the status report that is sent with beacons. It can send the frequency, any needed tone and the offset if it is a repeater frequency. The status text can be set to go out with every beacon or with every several beacons. This is set in MENU - StatusText... e.g. if it was set to 1/3 it would send it once for every 3 beacons. Currently, it also sends "D72" in the status text. This does take another 3 bytes, but tells anyone at a glance that the device sending the beacon is a D72 and that it is receive capable.

Currently, the "Kenwood" symbol is enabled. Symbols are sent in each beacon. Leaving it at the Kenwood symbol tells others that the device is capable of receiving messages. It wouldn't necessarily tell them if it was a TH-D72A, an old TH-D7A, or the mobile radios TM-D700 or TM-D710. The "D72" in the status text is unambiguous and could be useful. With set to 1/3, the voice frequency would also be sent every three beacons. If you were involved with something and needing to QSY often, you could change it to send the voice frequency every second beacon or even with every single beacon. For non-emergency use when you aren't changing voice frequencies very often, setting it to 1/3 will save a bit of bandwidth on the APRS frequency.

What can you do with APRS? Looking at it from the perspective of a D72, you can beacon your position report automatically. You can see other APRS stations around you, including the distance and direction. You can also send and receive APRS messages and receive APRS bulletins and announcements.

If you wish to view APRS activity around you, it can be done with nothing but a web browser. Go to http://aprs.fi and enter the callsign of the station you are interested in... e.g. VE7EMG-1 or VE7EMG-2. VE7EMG is the callsign, but the -1 and -2 are SSIDs... secondary station identifiers. There can be up to 16 SSIDs ranging from zero (not normally entered) to 15.

SYMBOLS

The station symbol is meant to convey information about the station. An appropriate symbol for a D72 would be the "Kenwood" symbol which would indicate that you were capable of receiving messages. For some situations, it might be useful to use among others the car, motorcycle, RV, sailboat, person (on foot), bicycle, Jeep (4x4), truck, boat (power), or van symbol. The symbol and table are selected in menus 3C0. Symbol codes and tables can be selected in menus 3C1 and 3C2. For some symbols, an overlay character can be used instead of the table.

APRS STATUS

Status text can convey additional information. A maximum of 42 characters can be entered. QSY information can also be included automatically in the status text... e.g. 147.320MHz Toff +060 would indicate that you were listening on VE7RSI's frequency, and that no tone was required, and that it is a plus 600 kHz offset. A compatible radio can use this information to automatically tune to your voice frequency.

The status text and QSY information is entered in menu 3A0.

SOUND

The D72 can alert you about several types of events.
MENU - Sound
RX Beep - OFF | ALL | ALL NEW | MINE - MESSAGES ONLY (good choice)
TX Beep - OFF | ON (when you transmit a beacon)
Special Call - enter callsign-SSID of other station (alerts you if heard)

CLUTTER

To some, it is clutter. To others, it is showing valuable information. If the screen is showing the last received beacon, you can press ESC (escape - left on the jotstick) to clear it.

<<<<<<<< ADD NOTES

PACKET FILTER

It is possible to limit the range of stations stored in the station list.

<<<<<<<< ADD NOTES

Receiving APRS Messages

You don't have to do anything to receive a message except have the radio turned on and listening to 144.390 MHz with the TNC in APRS mode. To view sent and received messages, press the MSG button... 4 on the keypad. It is useful to have sound enabled to alert you to a received message. See above. You can scroll up and down the list with the joystick. An arrow pointing to or from a callsign indicates if the message was sent to or from the station shown. Press OK (right on the joystick) to view a message.

Sending APRS Messages

UI-View

UI-View32 is a Windows based APRS client. You can download it from www.ui-view.net. The author Roger G4IDE became a silent key in 2004. There are other APRS clients. Only one other is in active development and making improvements. UI-View is still the "gold standard" and nearly sixteen years later, nothing has leapt to the forefront to take it's place. I have been hosting the UI-View web site since Roger passed away. In many ways, the website has been frozen in time. One of these days, I'll get in there and do a write-up on suggested APRS paths to reflect current practices.

UI-View can be used with static maps. There is also the PA7RHM map server that will fetch maps via the Internet. It does work, but it can be a bit slow updating the map as you zoom in and out. The nice way to go is the $50 Precision Mapping from Undertow Software. It gives you street level mapping for all of North America, plus ways to incorporate underlays to make it useful in other parts of the world.

Memory Channel Programming

A number of locally used frequencies are already programmed into the radio, but if you need to add a frequency to a memory channel, press VFO if not already in VFO mode. Press ENTER and then enter the receive frequency on the keypad. Verify the offset if it is a repeater frequency. Press function then MHz if the offset isn't correct. Enable a tone or CTCSS if needed. Store it in a memory channel.

how? <<<<<<<< ADD NOTES

Improvements...

Finally, this document can be improved upon. It is intended to be a guide. Reading the manual will be mandatory to get the most out of the radio. I should really read it one of these days! After more people have had a chance to play around with the D72As and go over this guide, don't hesitate to make suggestions if I have missed something important or if anything is unclear. I'll update it from time to time based on feedback from other users and from my own results as I try and learn a bit more about the D72 myself. See the date / time at the top of this document to see if you have the most recent version.

73 - Keith VE7GDH

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