Extraordinary Range in RF

Professional radio control and telemetry with an extraordinary range in the radio system in the free ISM band. FHSS configurable frequency hopping with excellent synchronization and fast recovery.

Up to 200Km maximum without repeaters for XLRS D1, D3 and D4 systems and 100Km max for D2, which covers almost any need.

To increase more the range or ensure good coverage in different conditions you can use smart antennas as repeaters in real time or as ISM cells (more information shortly). You can also link several transmitters D1, D2 or D3 that are in different places to a single drone or UAV to get more range and RF coverage.

5G RF. The radio frequency system is a fundamental part of the XLRS system. (Not to be confused with 5G of mobile telephony). 

It’s possible that you don’t need a lot of work range but if a lot of security in the radio link and in part this is given by the range of the system. There are different options of the same system with a scaling of ranges and prices to suit your budget.

The majority of options are by software, in this way the system is the same, you only need to buy a code, activate it and immediately have more range and features.

Learn more:


Differential and general characteristics of radio frequency XLRS





200km conditions: @50kb, antenna on TX Patch direccional 9dBi and omnidirectional 5dBi on flight LOS.

Remote Control RC, XLRS Telemetry and Mavlink symmetrical. 

Remember: Approximately every +9dBm in practice the range is doubled. 

Scalable range:

25Km.   Power: +20dBm (100mW).  Sensitivity: -99dBm.      Link 119dBm

50Km.   Power: +20dBm (100mW).  Sensitivity: -108dBm.    Link 128dBm

100Km. Power: +27dBm (500mW).  Sensitivity: -110dBm.    Link 137dBm

200Km. Power: +30dBm (1000mW). Sensitivity: -116dBm.    Link 146dBm


Simple calculation of the effective RF link: Resulting link + Antenna gain TX + RX antenna gain. (The attenuation of rain, clouds, etc. is not calculated). If you use extender cables for RF you must subtract the losses in dBm of extensors.

Example for 50Km: Link 128dBm + Patch antenna TX 9 + Omni antenna RX 5 = 128 + 9 + 5 = 142dBm.

Available repeaters (Smart Antennas) for real time ranges of areas of 600Km or more.




It is a very important parameter, especially if the temperature of the transmitter and the receiver are very different.

Controlled by TXCO. Better than + -1ppm. 

Only some few low end devices and low power (25mW), use XTAL adjusted to +-5ppm, even so it’s several times better than the RF chips need.

This excellent stability, does that when the systems are far away or receive the signal very weak the devices continue to work correctly. 

The master oscillator can be calibrated.

Systems with TXCO, practically don’t need it. To calibrate, you must have a frequency meter with a rubidium time base or stability better than 0.5ppm. 

 The systems with quartz crystal can be adjusted. (only by qualified technical personnel).




 Free Bands ISM or ICM (Industrial Scientific and Medical).

 Bands 866Mhz, 868Mhz, 902Mhz and 960Mhz, available and selectable by software.

 Other bands: 169Mhz, 433Mhz on demand.

 Multiband possibility Simultaneous with Smart antennas.

 Dual band simultaneously with two XPAD transmitters in pilot / co-pilot mode.

 You can extend the bandwidth (> 100kb) with smart antennas without decreasing range.





5G:  Fifth generation of RF modules manufactured by DMD.

Evolution of RF modules tested for FPV-UAV since 2007 with more than 1.100hours FPV flight from our I+D technicians.

Stop to the Fail Safeor failures of RF, If everything is correct, rarely our pilots or some customer has had some fail safe in 9 years.

CRC32: Authenticated and secure RF packages.

FHSS: Spectrum extended by frequency hopping, with improved synchronization that allows several channels to interfere and the system to remain synchronized and immune. New system with faster FHSS synch recoveries: <300miliseg. In the XLRS system the pseudo-random jump sequence also has user code (in preparation).

Encryption optional of RF DES/AES 128b packages. More information.


Password specific in the Radio Frequency network.




Selectable bandwidth: 50 or 100kb.

You don’t need auxiliary radiomodem, you save antennas and problems in flight. More clean installation.

Mavlink protocol integrated in transmitter and receiver.

Compatible with autopilots: Pixhawk, PX4, APM, etc and others with Mavlink protocol.





  The RF system uses a 32-bit IP address.

  Network and configurable IPs.

  List of up to 16 authorized devices (LEA) or authorized subnets, to be used without selecting several UAVs.

  Possibility to control “swarms” of Drones or UAvs. (Consult dmd@dmd.es).





Most XLRS systems have ACL radio commands.

Regardless of its functionality, the radio modules are compatible with the common commands for 5G radios.

You can send instant messages (SMS) to other XLRS-DMD devices in group or individually.




The transmitters (XPAD, suitcase GCS, etc.) can be connected to one or several Smart Antennas to extend their characteristics.

Increase reach in large areas with Smart Antennas high gain directional.

You can use several simultaneous ISM bands (169 and 868Mhz for example).

Use a network of Smart antennas as repeaters and get coverage without BVLOS direct vision in extensive areas with mountains.

Improve RF bandwidth without decreasing the range.



FHSS, Frequency Hopping Spread Sprectrum.

  The frequency hop provides more robust communications than with a fixed channel. In many countries its use is mandatory.

  Algorithm with improved synchronization that allows several channels to interfere and the system to remain synchronized and immune.

  40 hops/seg. Dwell time: 25mSeg.

        System with faster synch recoveries: <300miliseg.

  Works with 50kb or 100kb of bandwidth.

  Configurable start and end channels.


   XLRS systems: coding and encryption jump frequency. 10 bytes of code.

   Monitoring FHSS status in XPAD or BTSD and in DMDStudio.

   If you need a fixed channel, you can deactivate FHSS.

   More info FHSS, wikipedia


5G Radio.  Features.


RF Bands:                                   ICM 866, 868, 902, 915, 950Mhz.

Frequency:                                  From 866 to 950Mhz.

RF Channels:                               Band 866Mhz: 80ch, 50Khz    

                                                  Band 868Mhz: 40ch, 50Khz 

                                                  Band 902Mhz: 255ch, 100Khz

                                                  Band 915Mhz: 130ch, 100Khz 

                                                  Band 950Mhz: 100ch, 50Khz

Separation channels:                    50 or 100Khz according RF band

Bandwidth:                                  50 or 100Khz selectable according to baud rate 

Bandwidth (Radio Modem):              38Kb upload + 38Kb download for RF modem 100Kb.

Modulation:                                  2-GFSK. FHSS 40 hops/sec. or configurable fixed channel.

Aelectivity, Adjacent channel:         60dB to 12.5Khz offset. (@LNA Off) 

Blocking:                                       86dB to 10Mhz.            (@LNA Off) 

Power (According to license):          100mW(+20dBm), 500mW(+27dBm) or 1000mW (+30dBm)

Radiation 2nd harmonic:                 -27.5dBm 

Radiation 3rd harmonic:                  -43.5dBm 

Frequency stability:                        TXCO. +-1ppm

Sensitivity (According to license):    -99dBm, -108dBm, -110dBm ó -116dBm

RF input trigger level:                    Configurable in dBm (NCD command)

Rx Spurious:                                    <-57dBm

Working Temperature:                        -25ºC to +85ºC

RSSI:                                           Digital. Calibrated +-1dBm.

RC Packages:                                40 per second for RC and telemetry (25msec latency). 

Class of emission(radiation class):  100KFDDFW

RF Module:                                   Radio 5G DMD (WMX5H) (No to be confused with 5G of mobile telephony).

Upgradeable / Configurable:           With DMDStudio software through Mini USB port.

More information about radio system…