Climbing

● LIVE · 14 ms 4000 m FREEFALL ↓

What if the whole drop zone could watch — live?

SKYDIVE·LIVE

The Jump.
Live.

Real-time video from freefall.

The Problem

Today the ground sees
just a dot in the sky.

Spectators, the people waiting, the team itself — they follow the jump with the naked eye. The footage only arrives after landing. The moment itself stays invisible.

The idea behind it

What if the ground saw the jump
through their eyes?

Until now, freefall could only be retold — the footage always comes too late. We bring the view from the jump down to the ground, in the very moment it happens. Not a recording. The present.

The System

Two devices. One live image.

Its own radio link, no internet. The HDMI cable runs straight to the big TV in the waiting area.

Part 1

The Transmitter

The Product

Uses the GoPro mount.
Transmits 4 km — with margin.

GoPro format: lens in the protruding protective nose, the 1 W radio behind it — worn flat.

The radio heart

The transmitter.

Turns the camera image into a radio signal and broadcasts it at 1 watt — virtually lag-free (~14 ms). Reaches over 4 km, with comfortable link-budget margin.

⬡ Real off-the-shelf part — HDZero Freestyle V2 · colour = part ID

The eye

The camera.

A wide-angle skydive perspective in HD. The lens sits flush in the front wall — nothing sticks out to snag. Tool-less swap.

⬡ Real off-the-shelf part — HDZero Micro V3 · colour = part ID

The power

The battery.

3S LiPo (11.1 V) in the protected swap tray. BMS against over-/under-charge & short circuit · recessed contacts · thermally isolated. Charged externally, swapped tool-lessly.

⬡ Real off-the-shelf part — 3S LiPo, protected (BMS) · colour = part ID

The link

The antenna.

Flat patch antenna (35×35) flush in the side end-cap — the aluminium body is its ground plane, RHCP for clean reception; the top dipole takes over when the body shadows the patch. Final aim = jump test (our #1 check).

⬡ Real off-the-shelf part — TBS 5G8 RHCP patch · colour = part ID

Inside

Every part has its place.

Cover + tray printed (PETG) VTX sends the image Camera the eye Battery power Antenna transmits

Feasibility

From parts to transmitter.

Antenna patch · 5.8 GHz, beams down VTX 1 W · ~14 ms · 4 km Camera HD wide-angle · flush lens Fan adaptive · self-switching Battery 3S LiPo · tool-less swap Switch recessed on the edge · on at exit Cover + 4× M3 vented · moisture-robust, broken edges

Dimensions

GoPro format on the helmet.

78mmWidth

57mmHeight

56mmDepth

GoPro standard mounton the underside — fits any helmet mount.

GoPro width (~7 cm), worn upright — a bit taller & deeper, because a real 1 W radio, cooling and an all-day battery live inside.

Self-thinking cooling

The fan knows when.

The sensor reads chip temperature. The fan kicks in only when it gets hot — in freefall the airflow handles it; on the ground it runs on until everything has cooled.

Chip temperature Fan running

Responds to the real temperature — not a timer

All-day ready

Battery swap in three steps.

1 · Door

Flip the side door open — no tool, no screwdriver.

2 · Out

Pull the tray by its tab — the empty one slides out.

3 · In

Slide in a charged tray, close the door — it latches positively.

Like a GoPro battery door — but freefall-safe: snap latch + jump lock. Door on the side, out of ram pressure — holds against the ram pressure. Charge several trays in parallel.

What it enables

One transmitter —
many stages.

Competition

Public viewing

The championship live from the air — on the big screen on the ground.

Tandem guests

Live for everyone

Family, friends & those waiting watch every jump live on the TV — premium, not waiting.

Training & safety

Front-row seat

Instructors & examiners follow student jumps live from the ground.

Show

Live attraction

Freefall as a live image on any event stage.

The transmitter makes it possible: 4 km range with margin · ~14 ms — virtually lag-free · GoPro mount · all-day on a swappable battery · ready in seconds · legally clean via a PMSE short-term assignment (event) or 25 mW SRD (testing).

What becomes possible

Several jumpers. One screen.

Splitscreen of several jumpers POV feeds on one screen

Where it fits

Why not just DJI or GoPro?

	SKYDIVE·LIVE	DJI O3 / FPV	GoPro
Live image to the drop zone	Yes, open	own goggles/app only	—
Onto a big screen / TV	Yes · via HDMI	encrypted → no	—
Range	≈ 4 km	a few km	Wi-Fi ~50 m
Latency	~14 ms	~30 ms	n/a (recording)
Legally operable (DE)	Yes · PMSE/SRD	grey area	Yes
GoPro form on the helmet	Yes	no	Yes

SKYDIVE·LIVE14 ms

DJI O330 ms

Blink of an eye~100 ms

The image is there before you blink — a blink takes around 100 ms.

DJI transmits encrypted — you can't put the image freely on a screen. GoPro only records. Our niche: open, live, legal — straight to the TV at the DZ.

The transmitter at a glance

Everything that matters.

4000mExit altitude

5.8GHzHDZero band

14msLatency — virtually instant

4kmRange with margin

1WTransmit power · PMSE/SRD

78×57×56mmGoPro-near, on the helmet

Part 2

The Ground Station

From the sky to the TV

The image's journey.

From the jumper as a radio signal to two antennas, on to the monitor — and via HDMI onto the big TV. 14 milliseconds from the jump to the family in the waiting area.

What lands on the ground

Live on the
screen.

A monitor on the tripod catches the signal through two antennas — always the one with the stronger image. Daylight-readable, with a sun hood. Over HDMI the same image runs straight to the big TV in the waiting area.

Transmitterin freefall› Radio · 4 km5.8 GHz · 1 W› Antennasomni + patch› Monitor+ recorder› TV at the DZvia HDMI

Ground station with live image on the monitor

Antennas · omni + patch

Monitor · live image

Power station

Tripod

Field-ready

Set up in minutes.

Antennas

All-round omni + an aimed patch — together, seamless coverage of the jumper.

Recording

An external recorder captures it — instant playback after the jump.

Power

A power station for the whole day — even with no outlet at the DZ.

A real jump — followed live

Boarding

Honestly calculated

Range — with margin.

Distance: 4.0 km Link-budget margin: +9 dB

Solid — comfortable margin

Free-space link budget at 5.8 GHz / 1 W. At 4 km about +9 dB margin remains for body shadowing & multipath. The directional patch on the ground adds ~6 dB more — that's why there are two antennas. (drag the slider · switch antenna)

● RainThe radio loses < 1 dB over 4 km — almost irrelevant. The limit is visibility, not the signal.

● Clouds / sunNo effect on 5.8 GHz; the sun hood handles glare on the monitor.

● Wind / gustsThe hardware doesn't care — the limit is jump operations (VFR), not the transmitter.

The whole system

From the helmet to the
drop zone’s big screen.

›

Both halves fully engineered. The live loop is complete.

The path

From concept to the first official tests.

✓

Concept + CAD

Transmitter & ground station fully designed, collision-checked.

2

Prototype 1

PETG print, assembly, bench test (radio & thermals).

3

First jumps

Internal practice jumps — verify range & image for real.

4

Official tests

First real, official tests in summer 2026.

SKYDIVE·LIVE

Join in.

Jumpers, tinkerers, drop zones — let us build the front-row experience.

Appendix A · Radio link

The link budget, worked out.

Free-space path loss (Friis) at f = 5.8 GHz, d = 4 km:

FSPL = 32.44 + 20·log₁₀(f/MHz) + 20·log₁₀(d/km) = 32.44 + 20·log₁₀(5800) + 20·log₁₀(4) = 32.44 + 75.27 + 12.04 = 119.8 dB

Received level = TX power + antenna gains − losses − FSPL:

P_rx = 30 dBm (1 W) + 2 dBi (TX) + 8 dBi (RX patch) − 1 dB − 119.8 dB = −80.8 dBm RX sensitivity (HDZero) ≈ −90 dBm → margin ≈ +9 dB

Zero margin (free space) only at 4 km · 10^(9.2/20) ≈ 11.6 km. So 4 km is deliberately conservative — the ~9 dB absorb body shadowing, multipath & polarisation.

Method: Friis / ITU-R P.525. Values conservative (omni TX, unfavourable attitude).

Appendix B · Thermal

Why the VTX stays cool.

Dissipation at 1 W RF: the VTX really draws ~14–15 W (spec) → Q ≈ 13–14 W of heat — energy conservation allows nothing else (1 W leaves as RF).

Ground idle = the DANGER case: ΔT ≈ 13.5 W · (4–6 K/W) ≈ 55–80 K → marginal → doctrine: power up no earlier than 10 min before exit — the sender starts cold.

Freefall = the rescue: ram-air ≥ 55 m/s → forced convection h ≈ 90 W/m²K → R_th ≈ 0.43 K/W → ΔT ≈ 14 · 0.43 ≈ 6 K at −15 °C ambient at 4,000 m

Backed in hardware: ATtiny + NTC — fan ON 45 °C · warning 65 °C · VTX cutoff 75 °C (latch-off). Honest: all calculated; measuring Q on the real VTX is the open gate G1-T.

Method: steady-state balance Q = ṁ·c_p·ΔT + dynamic pressure ½ρv² (freefall ~55 m/s).

Appendix C · Airflow

The air path inside.

Two cooling paths — situational, not on a timer:

FREEFALL (primary): NACA flush inlet front → plenum → VTX heatsink → outlet rear Ram-air at in freefall: ~99 % pressure recovery, no power needed.

GROUND / POST-RUN: 25 mm fan (Sunon, 3.5 CFM) ducted onto the heatsink, ATtiny-controlled Inlet and outlet spatially separated ⇒ no short-circuit, real through-flow.

Battery decoupled from the VTX zone by the heat wall (LiPo < 45 °C). Vented, not sealed: GORE membrane + drain against condensation (4000 m / temperature swing).

Consistent with the cooling-logic slide: the fan follows the measured temperature, not the clock.