W4ZZK Josh and KU4WW Jeff teamed up to build the first WINLINK VARA FM Node in NW Alabama.
The modem is QRV on 145.030 MHz
Located on Colbert Mountain in Tuscumbia, AL
RF Transmitter Power is ~15 Watts to a 6dBd Vertical @ 120′ AGL
About VARA FM
VARA is a popular, proprietary, software modem that is used for transmitting and receiving data over amateur radio. VARA FM is an alternative to Packet and Pactor.
More In-Depth with VARA, by George, AE7G
WHAT IS VARA
VARA is a software program. It serves as a “sound card TNC” for use with radios. TNC stands for Terminal Node Controller. In basic concept a TNC translates certain computer files and commands into coded sounds. These coded sounds can then be transmitted via radio. On the receiving side the TNC translates the coded sounds back into computer commands and files where they can be used by the receiving computer. The original TNC’s were hardware devices and they are still on the market. Some of them are quite expensive. A new PACTOR modem costs in the range of $1500 not including cables. Kantronics hardware TNC’s capable of higher speeds go for $400 and up.
More recently designers have come up with TNC versions that are actually computer programs. These software programs use your computer’s built in processors to do the translating between coded sound and computer ready files and data. They also use sound cards to communicate sounds between the radio and computer. A Signalink is a sound card. So is a Masters Communications DRA-Series Radio Adapter Interface.
For operating VARA, it is best to use a radio that has been designed to work with an external TNC. These radios typically have a separate six pin mini DIN port. Kantronics set the industry standard for TNC’s and TNC compatible radios have generally followed Kantronics’ pin assignment convention. Radios with Kantronics type data port pin setups are also more likely to have the extra circuits that allow them to work with higher speed 9600 bps TNC’s.
LESSON 1: VERIFY THAT YOUR RADIO IS SET UP TRADITIONALLY. OTHERWISE YOU WILL NEED TO BUY OR BUILD AN ADAPTER CABLE. Instructions for how to do that are below. A sound card is a device that manages the use of sound by the computer. All computers with built in speakers and a microphone have an internal sound card. But these internal sound cards are not ideal for use with a sound card TNC. If you want speed and reliability you need clean, clear sound. You need to avoid interference, background noise and interruption from other sound sources. Any interruption or noise during a data transmission can slow down or completely disrupt the communication. For this you usually want a separate external sound card, these typically connect to the computer via a USB cable.
A decent sound card accepts audio direct from the radio, filters out extraneous noise and presents the purest and cleanest direct signal. By having a separate device you can tell your computer to run only VARA using this sound card, all other interruptions and noises generated by programs go through the computer’s regular sound card. Which brings us to Lesson #2:
LESSON 2: When using VARA you need to configure your computer’s sound card settings so the VARA program is the only one using the external sound card. We will explain how to do that later. This article deals with setting up a sound card for use on an FM radio, which means you are normally using VHF or UHF frequency ranges. With TNC connections in these radios there is an issue of SPEED. As a general rule the faster the speed of the modem the faster the data moves. The choice typically available in FM radios is between 1200 and 9600 bps.
I could explain what bps stands for but all you really need to know is 9600 is faster than 1200. When transmitting data, as a general rule the BANDWIDTH of the signal controls how much data can be communicated in a specified period of time. The wider the bandwidth the more data can be crammed into one second of transmission. Sounds are waves. Each tone has a particular frequency. The bandwidth of the sound signal is the RANGE OF FREQUENCIES the equipment can transmit or receive. How low of a bass, how high the treble. A sound signal with a wide range of frequencies can convey more information in a given time. Radios typically filter received audio signals so they sound better to the human ear. These signals are adequate for 1200 bps transmission. But for 9600 speed you need as wide a bandwidth as possible. To accomplish this, radios capable of handling 9600 have separate audio ports for the raw incoming signal that has not gone through the radio’s filtering.
LESSON 3: YOUR RADIO HAS A MENU SETTING THAT YOU NEED TO SET TO THE SPEED YOU ARE USING for data transmission (1200 OR 9600). When choosing a sound card for VARA, not all sound cards are equal. Some don’t take advantage of the full bandwidth available from your radio. You can still use these cards but they won’t give you as fast a speed as other cards with a wider range. The SIGNALINK generally has a narrower bandwidth, the Masters Communications DRA Series has a wider range and will work at faster speeds.
WHAT YOU NEED TO BUY
You should ideally have a radio that is capable of both 1200 and 9600 bps speed. You need 1200 for flexibility and you need 9600 to get the best speed. If you have a radio that is compatible with hardware TNC’s the radio will have a six pin mini DIN plug outlet. The standard for TNC’s is Kantronics and the radios compatible with that setup has the following pinouts for the 6 pin mini DIN:
DATA Input (transmitter audio)
Ground
PTT
9600 output
1200 output
Squelch
For VARA you only need pins 1, 2, 3 and either 4 or 5.
Masters Communications sells a DIN 6 adapter that allows you to match the DRA-30 or DRA-45 to your radio. The adapter ALLOWS YOU TO SWITCH BETWEEN 1200 AND 9600 BY SIMPLY MOVING A JUMPER. Basically the jumper chooses either pin 4 or 5 depending on your chosen speed of communication. You can check the pinout scheme by looking it up in your radio’s user instruction manual. It will be in there somewhere, probably towards the back where they talk about working with data modes and TNC’s. If your radio has the above pinouts for its mini din 6 connector you are good to go. Order the following from Masters Communications:
DRA-30, DRA-45, and DRA-65 have the DB9 while the newer DRA-36, DRA-50 and DRA-70 have the Mini-DIN-6, and don’t require the DIN-6 Adapter.
Case
DIN-6 Adapter (for DRA-30, DRA-45, or DRA-65)
You will also need to order a male mini din6 to male mini din6 cable. The Masters Communications DRAC-12 is a good cable. MAKE SURE the cable connects all six wires straight through. The DIN-6 Adapter has a number of jumpers. The only jumper you need to mess with is the one that selects between 1200 and 9600 speed. The rest should be good to go out of the box.
If your radio does not have the standard six pin pinout scheme listed above you will need to adapt a cable to match. The DRA-30, DRA-45, and DRA-65 have a DB9 connection. It has the following pin assignments relevant to VARA:
- Audio out – to the transmitter (microphone or modulator input)
- PTT
- Receiver Input (the sound cards microphone)
6: Ground
If you already have a SIGNALINK you can use it for VARA but you won’t get full speed. A few newer radios have built in sound cards. You won’t need a sound card for those radios but you will need a compatible cable to connect between your computer and the radio.
GETTING CONNECTED AND CONFIGURED
VARA has a free evaluation version but it will only operate at slower speeds. A one-time purchase gets you a lifetime individual license. You can use it only with your call sign but you can use it in as many computers and radios as you wish. You can get VARA here: https://rosmodem.wordpress.com/. There are two types of VARA, one for HF and the other for FM. One subscription gets you both. This article deals only with VARA FM setup. Install VARA FM in your computer and make sure you input the call sign and your license code if you bought a license.
CONFIGURE YOUR RADIO
You will need to go into your radio menu and set up the data speed. Each radio is different and each radio has a different menu system and menu conventions. Many radios with TNC connections also have ports for direct connection to a computer. These direct connections are typically used for radio codeplug programming and firmware updates. There may be menu settings in your radio that will set the speed of communication with a computer for programming. The speeds for this menu will have a wider range of choices than with TNC or data speed connections. Don’t get those confused, if you set say 9600 for this purpose it will not set your data speed for the TNC and your VARA session may not work. The data cable speed menu item will generally only give a choice between 1200 and 9600. That is the one you need to set and that needs to be consistent with the cable speed choice you selected.
Your radio may be a dual band radio. The radio may require you to specify which band (A or B) that is used for data. Make that selection and make sure you are on that band when you go to use VARA. It will only work if you are on the right band. When you use VARA you are actually operating simplex. You don’t want an offset and you don’t need a tone. Power depends on location but generally digital does not require as much power, and I would suggest starting with medium power.
CONFIGURE WINLINK
Current versions of WINLINK include menu entries for VARA sessions. You will be using the VARA FM session choices, VARA FM peer to peer or VARA WINLINK. Look at the Open Session drop down menu by clicking on the down arrow in the open session box. You should see both VARA FM WINLINK in the menu as well as VARA FM P2P. The VARA FM WINLINK session will be used in all your communications with a node. The VARA FM P2P will be used to communicate directly with another VARA FM radio that is in direct simplex range.
Now open up a VARA FM WINLINK session. Then open Settings, VARA tnc setup. The host address should be 127.0.0.1, TNC command port 8300, data port 8301, and the location of your VARA FM modem software should be specified. Also make sure the box is checked that automatically launches the VARA FM TNC when session is opened. These commands tell the computer to turn on your VARA soundcard modem automatically when you start the session. Update these changes and close the TNC setup screen.
Close the session then reopen. After the session is started you should see a separate item on the taskbar showing the VARA FM soundcard control panel. Click on it, you should see a window with four dials along the bottom, a green screen on the right above them, and a graph grid to the left. On the menu bar above click on settings, VARA setup. Make the following entries: Under TCP ports Command should be 8300, data 8301. Your call sign and registration key should be entered under call sign and registration key if you have registered. Under FM system, you will select NARROW if you are using 1200, WIDE if you are using 9600.
When you have all this entered close that screen. Note that you have set the same ports as in the previous menu. Now open sound card. You need to select the USB sound card for both the device input and output. Do not select your computer’s internal card for either of these settings. Now close that box. Open PTT. If you got a Masters Communications Radio Adapter (of any kind) select RA-Board. Close that setting.
CONNECT YOUR DEVICE
Assuming you are using a DRA connect it to the radio, using your selected cable. Turn the radio off before connecting. Also plug the computer side of the DRA to a USB port on your computer.
CONFIGURE YOUR COMPUTER SOUND CARD SETTINGS
Assuming you are using Windows 10, open control panel, and on the sound setting menu select manage audio devices. This opens a box that allows you to select preferences for your sound cards. For this to work your sound card needs to be on and connected to the computer. Make sure your computer’s built in soundcard is made the default for speakers and microphone. It needs to be the general default and it also needs to be the default for communications. This assures that only your VARA modem will use the RA soundcard and your session will not get interrupted. Next click on your USB soundcard under playback. Click on properties and this opens another box. From there select levels and this opens a screen you can use to set the volume level. Do the same thing under recording and set the microphone level as well. You can play with these settings to figure out your optimum level for best performance. See the comments below from Randy Neals concerning tuneup procedure.
STARTING A SESSION
Now start WINLINK. Select VARA FM WINLINK. Open the session. Go to channel selection. Choose one of the ACS VARA nodes near you. Make that selection. You should see the call sign and frequency displayed in the box at the top of the session window. Now make sure your radio is on. Tune it to the frequency specified in the session screen that you have selected. Make sure you DO NOT have an offset (plus or minus) set, remember this is a simplex connection. You also do not need a tone, and you don’t want your radio requiring a tone from the node, so no tones at all is the best choice. Now go ahead and start the session. You can click on the VARA soundcard screen to see how it is working.
TUNING AND VOLUME SETTINGS
The following are comments provided by Randy Neals explaining the tuning process. You can mess this to adjust your settings for maximum performance.
Tuning is dead simple.
RX Level
- When sitting there monitoring the channel, with no activity – Your VARA VU meter should read in the green, ideally about 1 o’clock on the dial.
- If you have the DRA Interface, adjust the RX level (large pot) so the VU meter is at 11 o’clock when receiving data.
TX Level
- In VARA FM click Settings, and the select Sound Card from Menu. The SoundCard window will open up.
- Tune your radio to the frequency of a node which you expect will have a good RF signal to your location.
- Click the RED autotune button on the right side of the SoundCard window.
- Enter the node callsign in the callsign box W7ACS-10, then click the electrical plug icon to the right.
Your radio should key up and will send 11 transmissions with increasing tone levels. At the end of the 11th transmission the gateway node will respond. Two numbers will be displayed in your SoundCard Window – a Signal to noise value, which is hopefully in the high 20’s or low 30’s ie: “27dB SNR” and the second number will be your transmit audio level setting, which is automatically adjusted. On my radios it runs between -4dB and -12dB.
Those of us who have gotten through the install process and have been making it work have been really happy with the speed at which this works. A lot of factors can affect speed, including signal path between your station and the node. ACS is adding high speed node stations at various locations and you will see more options open to you in the future.
Enjoy the speed!