Because the SATELLINE-4Pro is only available with “Survey Mode” firmware, Configuration Manager software is essential for loading a channel list and changing most settings. The most recent version of the software can be downloaded from our Support page.

Following are step-by-step instructions on loading a channel list to your 4Pro radio:

• Connect modem to your PC using a D9 serial interface cable or USB programming cable.

• Connect the 4Pro to power (check that you have the right voltage).

• Open SATEL Configuration Manager & click the “Program Preferences” tab.

• Confirm that the correct COM-port is selected and that the baud rate matches that of the radio (default baud rate of the 4Pro is 115200 bps). (Important: to be able to change settings, in the “Program Preferences” tab, under User Level Settings enter the maintenance password and login.)

• Select the blue “Connect” tab to fully access the modem settings.

• Select “Modem Settings” tab

• Select “Channel Selector”, blue button at the top right.

• If creating a new channel list, in the Channel Selector Window, select “Add” and the Channel Editor Form will appear. Here you can set the User Channel (1-XX), Tx and Rx Frequencies, Bandwidth (12.5, 20 or 25 kHz), and Channel Tx Power (NOTE: if Tx Power is left blank, the radio will default to the max. power of that unit and the saved channel list can be reloaded to any SATEL radio. See previous blog post here for more information.). Input your selection for the user channel and press OK. Continue this process for each subsequent channel, to complete your channel list. (If loading an existing channel list, in the Channel Selector Window, select “Load”, where you will then be able to browse for your saved CFG or CSF file)

• It is recommended that you then click the “Save” button, to save your new channel list to your PC.

•  When done, click “Close”. Change “Channel List In Use” to “ON”. The edited settings will show in red font. 

•  Select the blue “Write Settings” button. Once complete, these settings will change to black font, indicating they’re loaded to the radio.

•  We recommend you select “Save Configuration to File” to save all specified settings to your PC, before selecting “Disconnect”.

For additional questions, or if you’d like to suggest a technical topic for us to review in our blog, please email support@satelusa.com.

Error Correction is an available setting in all SATEL radio modems, which can help improve data transfer in cases of poor or unreliable communication. Referred to as FEC Mode (Forward Error Correction) in Configuration Manager, note that this setting refers to SATEL 3AS Error Correction and does not affect other compatibility modes, such as PacCrest. This setting can be turned ON or OFF both in Configuration Manager and directly on the front screen of your radio modem.

When Error Correction is enabled (ON), the radio modem automatically adds additional error correction information, which increases the amount of transmitted data by 30%. It is used by the receiving radio modem to correct erroneous bits, as long as the ratio of correct and erroneous bits is reasonable. The resulting benefit can be an improvement of up to 3dB sensitivity.

Error Correction improves the reliability of data transfer via the radio interface, especially in unfavorable conditions. The Error Correction function should be used when link distances are long or received signal is otherwise low due to poor propagation conditions or multi-path fading. It is also recommended to use Error Correction in case there are intermittent interferences on the radio channel.

The Error Correction function decreases data transfer throughput by approximately 30%. Though transfer delays are longer, Error Correction can be quite useful for the best data transmission quality in the scenarios described above.

Myth: Double power will double the distance of my transmitter.

It is a common misconception that in order to achieve twice the distance in a radio link, you can simply double the power. The reality is that in order to double the distance, 4 times the Tx power is needed. This rule comes from a simple geometric formula: the propagation of radio waves expands in the shape of a sphere, and the surface of a sphere (and thus power density) changes proportionally to the square of the radius (in this case the radius = distance).

To put it simply, if with a 1 Watt transmitter you can reach 1 mile, in order to reach 2 miles you will need a 4 Watt transmitter. Of course the distance depends not only on the power of a transmitter but also–and very much so–on the antenna gain and height, the quality of the receiver and on the obstacles in the terrain.

A very useful way to calculate radio links parameters is using dB’s. In this case, mathematics show that doubling the power is the equivalent to increasing the power by 3 dB. It can also be demonstrated that doubling the distance is the equivalent of an increase by 6dB.

Seen below is a table of equivalence between Watts and dBm.

Repeater Mode can be easily set up from the front screen of any SATEL radio (Main Setup>Additional>Repeater>select ON>Save changes). Many SATEL users stop there, however additional steps can be taken in order to prevent potential issues with your system. Some rather common issues we hear about when a repeater is in place are:

“I get a signal when near the base, but not when near the rover”

“I’m getting a signal, but not getting a fix”

“The rover sometimes hears both the base and repeater and it looks to be creating issues with my GPS”

The first scenario is likely an antenna issue; you will want to check your antennas and cables. The second scenario is likely due to parameters; you will want to go back through your settings and make sure parameters match. The last issue of an “echo” or double signal is a common problem you’ll experience with a repeater, especially in Precision Ag applications, or other scenarios in which the rover is moving. Some GPS are immune to the echo, while we’ve seen others get confused by the double signal. Here are some tips for fixing this common issue, depending on your licensing:

If You Have More Than 1 Frequency:

If in your licensing you have more than one frequency available for use, we recommend using separate TX/RX frequencies. For example, let’s say you have 469 MHz and 462 MHz available. You would set up the base to transmit at 469 MHz. You would set up the repeater to receive at 469 MHz (Main Menu>Radio Frequency>RX Frequency (change setting)) and to transmit at 462 MHz (Main Menu>Radio Frequency>TX Frequency (change setting)). Then you will set the rover to receive at 462 Mhz. This will ensure that even if the rover hears the base at times, it will not receive and interfere with the communication.

If You Do Not Have More Than 1 Frequency:

The alternative option, if you do not have more than one frequency available to use in your application, is to set up addressing. This is easily done through the programming software on your PC, using either Configuration Manager or SaTerm. The set up would look like this:

Base = Address 0001 0001

Repeater = Receive Address 0001 0001, Transmit Address 0002 0002

Rover = Address 0002 0002

As above, this also ensures that the base will not interfere with the rover, even if a double signal can be heard at different points.

Other Common Issues:

Another common issue in repeater set ups relates to modulation settings. Using a slower protocol, such as GMSK, is not recommended on a repeater set up because of the length of the data stream. The data string nowadays are so long that it can create a back up of data; the repeater may still be transmitting to the rover as the base is trying to send the next string. This can be resolved by using a faster protocol.

Set up should also be considered; we have seen numerous situations in which the repeater is placed too close to the base, instead of near the rover. You want to make sure the repeater and rover are as close as possible in order to ensure the best signal.

Double repeater set ups are much more complicated, especially when the rover is moving. Addressing, as described above, is recommended in this scenario.

Even if the summer heat has passed, the heat dissipated by a 35 Watt radio can be an issue any time of year. It is perfectly normal for a 35W transmitter to generate enough heat to be very uncomfortable to the touch. Any transmitter of any major brand consumes energy equal to about three times the radiated power. In the case of a 35W transmitter, that is about 105 Watts. As a comparison, a 100 Watt light bulb cannot be touched when it is on because it is too hot to be handled. Something similar happens to a radio, although there are various steps you can take to decrease this large amount of heat.

The first precaution the manufacturer takes is that a radio of 35W power is equipped with a heat-sink. Note that the heat-sink, normally mounted on the back of the unit, is only effective if air circulates freely without obstructions, and circulates vertically. A radio mounted horizontally will heat up much more than one whose flow of air can freely flow from bottom to top.

A potential source of overheating can be in RTK equipment working with multiple constellations, thus requiring longer strings of data to be transmitted each second. This means that the transmitter will stay on for a longer period of time, generating more heat. The solution is a higher over-the-air speed, which will in turn reduce the transmission time. For example, a base radio sending RTK corrections to a rover utilizing a GMSK protocol will generate almost twice as much heat as a base radio using a faster protocol like 4FSK (at the same bandwidth). The difference can be dramatic.

Another undesirable source of heat is the so-called “reflected power”. All the RF power of the radio should reach the antenna and should be radiated in the form of electromagnetic energy. If some of it returns back to the radio, the radio will heat up considerably more, not to mention that the working range will be reduced. In order to prevent reflected power, it’s very important to use a good RF cable with no damage and to make sure that the antenna is in good working condition without connector oxidation or other visible damage. Also, many users who utilize a steel whip antenna may not be aware that this type of antenna requires “tuning” to the right operating frequency. Normally such antennas are sold at a length which is optimal for the lowest frequency of its range. When a higher frequency is used, the operator should then cut it to the right length, as listed in the antenna instructions. Many users disregard this “fine tuning”, thus somewhat reducing their working range and increasing the heat (however only marginally).

Even if all the above is taken care of, when a radio is left operating in full sunshine on a hot day, it will inevitably heat up. SATEL radios have an internal protection that prevents damage once the radio reaches 176°F (80°C). The radio will continue to operate at reduced power, and the screen will flash to alert the operator.

Your best course of action if you believe heat has become a problem, especially in the summer or in warmer regions: reduce the power of the transmitter from 35W to 25W. It may be counter-intuitive, but this reduction of power (about 30%) will not affect the range very much. In fact, the range will decrease by about 15%, with the potential of saving you from a lot of downtime.