# Counter-drone detection mast

> Build a ground mast that detects and locates small drones: a direction-finding antenna and receiver on a mast, with solar power and a battery, checked for wind.

Source: https://tryspeed.ai/docs/examples/drone-detection-mast

You'll get the sensing half of a counter-drone system: a mast about two metres tall with a passive direction-finding antenna and receiver on top, a solar panel, a battery box and a steel base plate. Speed checks it for balance and stiffness and runs FEA for a wind gust. A first build takes about 2 minutes.

> **Before you start:** Speed is connected to your chat and your Speed tab is open. If not, do the [Quickstart](https://tryspeed.ai/docs/quickstart.md) first: it takes about two minutes.

> **Why detection, not interception:** Claude declines to design anything whose purpose is to knock drones down. Asked for "a drone blocker that spots small drones and knocks them down", it offered the detection half instead. This example is that detection half. See [What the chat won't design](https://tryspeed.ai/docs/limits.md#what-the-chat-wont-design).

## Step 1: Paste the prompt, then give the brief

Start a new chat, paste [the Speed prompt](https://tryspeed.ai/docs/prompt.md) and send it. When Claude asks **What do you want to build?**, type:

Type this:

```
A counter-drone detection mast for a small site: a passive direction-finding antenna and receiver on a mast about 2 m tall, powered by a solar panel and a battery, on a steel base plate. It must stand up to a strong wind gust.
```

Then switch to your Speed tab to watch.

## Step 2: Read the plan

The mast height, the sensor type and the power source are **stated**. Claude **assumes** the rest, for example the wind speed, the battery chemistry (often LiFePO4), the panel size and how long the sensor must run on battery. Speed has a ready-made passive RF drone detector, SKYSENSE, so Claude usually starts from it.

## Step 3: Watch it build, stage by stage

1. **Start.** Claude loads Speed's SKYSENSE passive detector as the sensor head.
2. **Base and mast.** A steel base plate and a mast tube of about 2.1 m, with the antenna and receiver on top.
3. **Power.** A solar panel (around 100 W) on the mast and a LiFePO4 battery box near the base, where the weight helps stability.
4. **Check.** The physics check makes sure every part touches what holds it. Claude takes a picture to check the panel doesn't block the antenna.
5. **Wind.** Claude sets a named wind-gust load case and runs the FEA. On the live run, the first mast bent too far, so Claude chose a bigger mast tube and ran it again. Expect the same kind of fix.

## Step 4: Read the summary

You'll get the total mass, how long it runs on battery alone, the lowest safety factor in the wind case, the first sway frequency of the mast, the verdict and every assumption. Claude also lists open warnings, for example a thermal margin it could not close (electronics in a sealed box in the sun).

## Follow-ups to try

### Run FEA for a stronger gust

Type this:

```
Run FEA for a wind gust 50% stronger than before and tell me the weakest part.
```

Claude adds a named load case, runs the FEA, and reports the most loaded part, its safety factor and how far the top of the mast moves.

### Swap the battery and compare

Type this:

```
Swap the battery for the next size up and compare.
```

Claude fits a larger battery and shows before and after: mass, runtime on battery and stability.

### Make the one-pager

Type this:

```
Make the one-pager.
```

A one-page drawing sheet with views, a parts list and notes opens in your Speed tab.

### Fix the thermal warning

Type this:

```
Close the thermal warning without making the mast heavier. Show me before and after.
```

Claude changes one thing at a time, for example a sun shield or vents on the electronics box, and reruns the checks.

## What to check before you trust it

- Speed models the mast, the power system and the structure. It does not model radio detection range, direction-finding accuracy or the receiver's software.
- Wind loads are screening grade. Check them against the wind code for your site.
- An engineer must review the design before it is built or installed.

> **Note:** Your numbers will differ from anyone else's run, because Claude picks its own defaults and catalogue parts. What matters is that every assumption is listed. Change any of them by saying so.