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Ligne 1 : − == Introduction ==+ − What ever you do, the antenna is always one of the most sensitive component when working in the radio area. − − The following schema shows how to wire the RFM69HCW to transmit data. − − [[Fichier:ENG-CANSAT-RFM69HCW-TEST-00.jpg|520px]] − − As you can see, the antenna is made of a simple wire. − − Remove the wire and the data would not transmit at 1 meter of distance, even on the same desk! − − Remember, '''the antenna is the key to transmit data over a long distance!''' − − == Antenna connector == − The radio modules usually offer a spot to solder antenna. − − With the RFM69HCW the antenna spot allow you to connect an antenna in 3 different ways. − − [[Fichier:ENG-CANSAT-RFM69HCW-Antenna.png|240px]] − − Later on, you would focus on antenna choice: − * A wire inside the antenna hole (also said a ''wire dipole'' or ''simple dipole''). − * A {{pl|1418|µFl connector}} to plug antenna. − * A {{pl|1419|PCB SMA connector}} also to plug other kind of antenna. − − The cheapest antenna is the wire antenna (''simple dipole'') and the best option is the SMA connector (also mode heavy). − − The {{pl|1418|µFl connector}} (also named uFl) is looking to this: − − [[Fichier:ENG-CANSAT-RFM69HCW-TEST-uFL-connector.jpg|150px]] − − A {{pl|1419|PCB SMA connector}} is looking to this: − − [[Fichier:ENG-CANSAT-RFM69HCW-TEST-SMA-connector.jpg|150px]] − − == Yagi Antenna == − While reading [https://arduino103.blogspot.com/2018/08/ballons-meteorologiques-tout-savoir-sur.html some resources on the QSO magazine] (Magazine from Belgian Radio Amateur Association written in dutch and french), we did discover a Yagi Antenna tuned for 433Mhz. − − [[Fichier:ENG-CANSAT-ANTENNA-10.png|640px]]<small><br />Source: QSO Magazine via [https://arduino103.blogspot.com/2018/08/ballons-meteorologiques-tout-savoir-sur.html this publication] - '''click to enlarge'''</small> − − This antenna was engineered from the "[http://df.mchobby.be/ballon-meteo/cheapyagy.pdf Cheap Yagy]" (''pdf''), issue from the "[http://www.wa5vjb.com/yagi-pdf/cheapyagi.pdf Controlled Impedance 'Cheap' Antennas]" article written by Kent Britain WASVJB. − − A simple rule of three can be used to adapt the antenna to other frequencies (the antenna was already adapted from a 432 Mhz design). − − === 6 or 11 elements === − The Yagi antenna showed here upper does have 6 elements. − − From a deeper read of the [https://arduino103.blogspot.com/2018/08/ballons-meteorologiques-tout-savoir-sur.html QSO magazines series], we learned that 6 elements Yagi can offer a gain up to 11.2 dBi. − − It seems that the 11 elements Yagi ([http://df.mchobby.be/ballon-meteo/cheapyagy.pdf see original document]) '''will double the gain'''. Whoaw!!! − − == About Yagi Antenna == − === Radiation Pattern === − The radiation pattern is the direction or direction'''s''' where the signal will be emit (or received). − − The dispersion − − === Common Design === − The antenna lengths and spacing are depending on the wavelength to capture. − − [[Fichier:ENG-CANSAT-ANTENNA-30.png]]<small><br />Source: [https://www.elprocus.com/design-of-yagi-uda-antenna/ design of Yagi Uda Antenna]</small> − − * '''Directors''' : used to drive the signal in the given direction. Those directors are usually shorter than driven element (about 5%). − * '''Driven element''' : is the element that capture or emit the signal. − * '''Reflector''' : reflect the signal toward (or coming from) the driven element. The reflector is larger than driven element (about 5%). − − Because of the antenna design, the maximum of radiation is in the way of director. − − [[Fichier:ENG-CANSAT-ANTENNA-31.png]] − − === Resource === − * [https://www.elprocus.com/design-of-yagi-uda-antenna/ Yagi Uda Antenna] (''elprocus.com'') − * [http://www.rfwireless-world.com/Terminology/Advantages-and-Disadvantages-of-YAGI-UDA-Antenna.html Advantages & disadvantages of YAGI antenna] (''rfwireless-world.com'') − − == CanSat and Antenna == − As specified by the CanSat settlement, everything should be contained within a defined volume (the Can). − − So, the antenna should also fit into the volume. − − However, '''once the can is released in the air, your project can deploy an antenna'''. − − A well designed antenna for sending the data would also reduce the error ratio on the ground station. − − == Getting Help for Antenna == − Designing and testing an antenna for long distance communication is an intensive work. − − You could find some help from our Radio Amateurs friends. − − To locate a [http://map.mchobby.be Radio Amateur Club] near of your home then have a look [http://map.mchobby.be the "Maker's Maps"] owned at MC Hobby. − − [[Fichier:ENG-CANSAT-ANTENNA-20.png|link=http://map.mchobby.be]] − − A '''yellow mark''' indicates the Radio Amateur clubs.
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