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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 emitted (or received). − − So for a given transmission power, a directional antenna would send the signal further than an hemisphere antenna. Indeed, directional antenna would concentrate all the power is one direction where as hemisphere antenna would spread the same power all around. − − === 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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