Radio Research

[devsamuelv]

Radio Communication Research

Summary

Research what's needed to establish reliable radio/wireless communication with the rover across the competition course, including hardware options and frequency considerations for non-line-of-sight (NLOS) conditions.

Background

The course has hills that will block direct line of sight to the rover in some areas. Our wireless link needs to be planned around this, not just assumed to work like an open-field setup.

Requirements

• Range: Minimum 2 km
• Line of sight: Must work without line of sight (NLOS) — hills on the course will block direct sight to the rover
• Price: $100 or less
• Ethernet: Preferably supports connecting other devices via Ethernet

Reference Hardware

• Omada Wireless Bridge — EAP211-Bridge KIT (v1.6)
  • 802.11ac, 5 GHz band, up to 867 Mbps
  • Rated for long-range transmission up to 1 km (line-of-sight, open area)
  • Auto-pairing, centralized management via Omada SDN
  • Point-to-Point (PtP) or Point-to-Multipoint (PtMP) modes
  • 3x Gigabit Ethernet ports, IP65 weatherproof, outdoor-rated, PoE powered

Note: This kit's 1 km range spec is based on open, obstacle-free line-of-sight conditions.

Tasks

• Research which wireless frequencies/protocols work well NLOS at 2+ km (e.g., sub-1 GHz options like 900 MHz, LoRa, or other long-range radios that diffract around obstacles better than 2.5 GHz)
• Compare range/throughput tradeoffs: lower frequencies (better NLOS penetration, longer range, lower bandwidth) vs. higher frequencies like 2.5 GHz (higher bandwidth, shorter NLOS range)
• Identify options that fit the $100 budget — note that many long-range outdoor bridge kits (including the EAP211 reference above) exceed this, so budget radios/telemetry modules may be the better fit
• Review last year's competition rules for any restrictions on frequency bands, transmit power, or equipment: 2026 Rules Reference (Google Drive)
• Summarize findings in a comparison table (range, NLOS performance, price, Ethernet support) with a recommendation

Open Questions

• What is the actual maximum distance and terrain profile (hill height/spacing) between our base station and the rover on the course?
• Does the competition ruleset restrict allowed frequencies, power output, or antenna types?
• Do we need a repeater/relay station if no single link can maintain connection across the whole course, and does that change the per-unit budget?
• Is the $100 budget per unit or total for the link (base + rover side)?

Deliverable

List of the wireless bridges evaluated including details like device frequency, power requirements, cost, protocols supported, maximum distance, and a short explanation why it would work/wouldn't for our project. Please include all devices evaluated even if they meet the distance and line of sight requirement even if they are expensive or power hungry.

[devsamuelv]

Report from Ariel (9/19/2026)

Products:

1. TP-Link CPE210 – Outdoor CPE:

• Key features: Up to 300 Mbps IEE 802.11n wireless performance, built-in 9 dBi 2x2 dual-polarized directional MIMO antenna, 65 degrees horizontal-plane antenna beamwidth, 35 degrees elevation plane antenna beamwidth, system optimization for 5km+ outdoor wireless links, Pharos MAXtream TDMA Technology, multiple operating modes, etc.
• Overview: This product has the benefit of the huge range that it provides, it uses 2.4GHz, so it can handle minor dips and bums better than a 5GHz product, built in Ethernet port which could be use to plug it into the rover computer if it has one. The negatives are that we would have to buy 2 of them one for the rover and one for us when we are at the competition so the price would be around 90$-100$ and it wouldn't handle the entire 2km being out of sight
• Link: https://shop.ntsdirect.com/product/CPE210-Z/TP-LINK-CPE210---Outdoor-CPE.html

1. Ubiquiti NanoStation AC Loco 5GHz :

• Key features : 560 MHz Atheros MIPS 74Kc Processor, 64MB DDR2 Memory, 1.8:1 Max VSWR, 45 degrees Beamwidth, Dual Linear Polarization, Outdoor Stabilized UV Plastic Enclosure
• Overview: This system is very easy to work with due to its built in software interface that runs straight from a web browser and is preferred by a lot of robotic clubs but the big issue is because it runs of 5GHz it will not be useful for when the rover get's out of sight but if we somehow overcome this it will easily handle the 2km requirement, nevertheless this a relatively cheap option 49 dollars per unit, it must also be noted that we must check off its auto selection because as stated by the rulebook our frequencies cannot interfere with the other teams frequencies and we must also reduce its channel width to 20MHz to follow the rule book
• Link: https://store.ui.com/us/en/products/loco5ac

1. KuWfi 2-Pack CPE Wireless Bridge 2.4 GHz 300 Mbps 12dBi Point to Point Wifi Extender

• Key features: 12dBi dual polarized directional antenna, data range 2.4GHz up to 300 Mbps, Wall-Mounting or Pole Mounting , can make it to the 2km, it can work two units at the same time, sunscreen shell
• Overview: We would need to reduce the channel width to 20MHz to abide by the competitions rule, it comes pre set so it's the easiest to handle out of all the options, it has dual ethernet ports, its capable of reaching 2km but it's reaching its limits so that's something to keep in mind, similarly to the TP if is completely out of sight, for example if is behind a rock, the connection will drop to 0, it can be bought trough Sears Marketplace
• Link: https://kuwfi.com/products/products-kuwfi-2-pack-long-range-wifi-extender-outdoor-wireless-bridge-24ghz-300mbps-pre-configured-nano-station-indoor-outdoor-poi

Final Opinion:

• In my opinion the best product that I was able to find is the TP-Link, but I understand that the fact that it can't make it through the out of sight requirement is important to note. A way to fix this could be by buying an extra unit and putting at the top of the tallest hill so that way it can see the rover at all times and then we can send the signal from the computer to the extra unit and then that unit sends it to the robot.