Should we prioritize enhancing the antenna or boosting the transmit power?
Should we prioritize enhancing the antenna or boosting the transmit power?
Good evening everyone, discussing a project in its initial planning phase. For long-range communication in IoT initiatives, should we prioritize enhancing the antenna or boosting the transmit power? How can we ensure compliance with local transmission regulations? What’s your recommendation—should we focus more on one aspect over the other? Background: We aim to establish a project capable of extended signal reach. Also, how would you increase the current transmit power?
Usually the FCC in the US sets a modest maximum for unlicensed transmission power, which varies by frequency band. You also need to avoid interference from other signals, so simply increasing power may not be effective. It's rare to design an antenna that works well in all directions; instead, directional antennas are preferred for focused communication. For IoT applications, Wi-Fi is a good choice if range is insufficient. If coverage is too limited, consider cellular options.
When operating on battery, enhance the antenna. On wall power, boost transmission strength. At the edge of transmission limits, refine the antenna. If both are at full capacity, optimize data encoding. In short, there’s a lot we don’t know here. Could you share more about your project? Also, please let us know if you have any licenses and your location—especially if you’re near an airport.
Hello everyone, this is so awesome - and you guys make me so happy. btw: i am a bit short of time - soon have to leave the house to catch the train... First of all, thank you for your responses! You've already brought up many exciting points, and I’d like to address them. On the topic of antenna vs. transmission power: The replies have made it clear that the choice between improving antenna design and increasing transmission power depends heavily on the use case. @Electronics Wizardy: Many thanks - for the steppin up the plate!!! and for the headsup: Your point about FCC regulations and legal restrictions is very relevant, especially for unlicensed usage. Well - i’m planning to work in the 2.4 GHz or 868 MHz bands, as they are widely used and relatively well-regulated here in good old Europe. Do you have any recommendations for antenna types suitable for these frequencies? For example: Is it worth building a kind of a DIY Yagi antenna, or should I stick to reliable, commercially available models? and i am very thankful for ll the practical recommendations you have made: @OddOod: glad bout your ideas you come up with: and i found your clear distinction between battery-powered and wall-powered setups really helpful! My project will be battery-powered, so the focus should indeed be on improving the antenna. Regarding data encoding: Do you have specific protocols in mind that are particularly efficient? LoRa, for instance, is known for long-range communication with low power consumption—could this be a good approach? on a sidenote: i am so glad to be here in the forum: its such a great place for all the idea exchange: i am happy that you share the insights from experience: @GuiltySpark: Your experience from the RC/FPV scene is incredibly valuable - and helps here alot: If antenna design made such a significant difference even with minimal transmission power, could you recommend any resources or tutorials for designing or optimizing antennas? Are there some good docs and papers out there? And on a sidenote: Would an omnidirectional antenna be suitable for IoT sensors in a mesh network, or would you suggest going for directional antennas instead? About transmission power and technology: As some of you mentioned, increasing transmission power depends on the transmitter. I’ve been considering the Adafruit RFM95W (LoRa module), which provides up to 20 dBm transmission power. This should remain within legal limits. Do you have any experience with such modules and tips on maximizing range while staying compliant with regulations? some background things to the project context: The goal is to establish communication over approximately 2–5 km (line-of-sight), primarily for transmitting sensor data (e.g., temperature and humidity). High-speed data streams are not required—sporadic but reliable transmissions are the priority. I’d love to hear more of your insights, especially on antenna design for such projects and any practical experiences with LoRa/IoT setups. Best regards, and as i allready mentioned: you guys - you help me alot: i am so glad to be here in the forum: its such a great place for all the idea exchange: i am happy that you share the insights from experience: keep up this awesome place... ps - now i have to hurry up - need to catch the train .... yours d-hubs
It seems you're pointing out some minor issues with the setup. No worries, just focusing on the basics. You’ll likely do fine with a good directional antenna and don’t necessarily need a full dish. Checking out EmbeddedFM would be a great next step—they’re a solid source for what I know about this.
Directional antenna, no debate. If you have strong output but only 96% reaches the intended path, the rest is wasted. In contrast, using a narrower beam—like a flashlight—can achieve effective coverage within a tight area, about 15-20 degrees, around 25 dBi or more. There are diagrams that clarify how signal reach relates to dBi values.