BOM.md

SkyLive — Bill of Materials

Prices as of 2026-07, EU/DE vendors, from the project's real order log (German original: BESTELLLISTE_SENDER_FINAL). Stock and prices rotate daily in FPV shops — verify on the day you click. Items marked “—” were already owned or not in the logged order.

1 · Sender — the four functional parts

#	part	exact product	≈ €	note
①	VTX + camera + MIPI	HDZero Freestyle V2 VTX Kit (incl. Nano90 camera, MIPI cable, stock antenna)	179.95	cheaper than buying VTX (118.95) + camera separately
②	Battery	Tattu R-Line 3S 850 mAh, XT30 (850 flight unit) · Tattu 3S 300 mAh HV (mid + Mini 300; measured 45 × 17.5 × 15.3 mm)	14.99	×3 bought for bench rotation; cold-rated packs only for the real jump
③	Switch	12 mm latching push-button, pre-wired (2 A / 12–250 V)	~5	Amazon-class part; voltage/current-safe for 3S @ ~1.3 A
④	Power joins	solder + heat-shrink (flight build) or 3× Wago 221-412 lever clamps (quick-build)	~3	the soldered build is the recommended flight configuration; the Wagos are the re-openable first-assembly path

2 · Antenna path (one SMA joint inside — U.FL touched exactly once)

part	role	≈ €	note
TBS SMA pigtail, U.FL → SMA flange, 60 mm	the fixed inner joint that protects the VTX U.FL (~30 cycles)	5.99	×4 bought (spares — treat as consumable)
Lumenier AXII 2, RHCP, SMA	the donut omni — captive against the short case wall, axis horizontal through it, coax held by the screw-driven T-clamp	—	73 × 17.5 mm, 7.8 g, 2.2 dBic, 5.3–6.2 GHz (manufacturer page)
TBS 5G8 patch, RHCP	legacy study only — the down-patch variant survives as an engineering study, not a fitted part	11.90–14.90	⚠ exists in SMA and RP-SMA variants — the study's patch is RP-SMA; match your pigtail, SMA ≠ RP-SMA
SMA↔RP-SMA adapter kit	catch-all for any connector mix	~6	Amazon kit

Antenna test kit (bought deliberately — the shoot-out is part of the project's honesty)

part	≈ €	why
TrueRC OCP 5.8 omni, RHCP, SMA (×2)	15.99 ea.	omni comparison candidate
Foxeer Micro Lollipop, RHCP, U.FL	18.90	budget omni comparison
TrueRC Matchstick Carbon Long, RHCP, U.FL	29.90	premium omni comparison
Linear λ/2 dipole, U.FL	1.85	only to demonstrate the −3 dB polarization penalty vs a true RHCP omni — not a fitted part

3 · Case & assembly consumables

part	≈ €	note
PETG (prototypes) / ASA (final) filament	~25/kg	never PLA — it softens too low; case files TBD-CAD-M6
Silicone thermal pad, 1.5 mm, ≥ 3 W/mK	~8	VTX face → wall, mandatory
M3 heat-set inserts (Ruthex RX-M3x5.7 class) + M3 screws	~10	roof-lid corner posts
M2 DIN 912 cap screws: 4× M2×8 (antenna T-pieces) + 1× M2×6 (door tab) + 4× M2×8 (XT30 latches) + 2× M2 (camera)	~4	all cap-head (project standard)
M2 brass heat-set insert, Ø3.2 × 3.0 (measured)	~1	door-tab thread — the most-cycled screw (every battery swap) gets brass, not self-tapped PETG; T-pieces/latches stay on Ø1.7 printed cores (low-cycle)
TPU filament	~15	only needed for the legacy capsule study (tip pad + root ring) — the anchored-omni build uses none
Heat-shrink, RTV/hot glue, zip ties	~5	Wago securing + strain relief
Soft foam padding, ~2 mm (EVA/PE)	~3	mandatory battery preload — the pack must never fly free in the bay (a loose 80 g pack hits ~590 N on a hard stop; the foam cuts that to ~250 N)
50 Ω SMA dummy load	~8	safe bench power-up without an antenna

4 · Ground station — several fixed beams (self-printed helix antennas)

The doctrine changed: no tracker, no combiner — multiple fixed beams (zenith + horizon), the receiver fuses the branches. The beams are self-printed 5.8 GHz axial-mode helices (RHCP, 7 turns, C/λ 1.00, pitch 10.5°, cup reflector with copper tape inside, HPBW ~37°). Gain, honestly: estimators span 10.7–13.9 dBic — measurement decides. Unscrew the BoxPro's stock 2 dBi stubs (one bad branch degrades the fused picture) and Wi-Fi-scan the DZ before operating.

part	role	≈ €
HDZero BoxPro	4-way diversity RX, Mini-HDMI out to the TV	~360–420
Helix antenna, self-printed (per branch): ~45 cm of 1.5 mm bare copper wire, 0.3 mm brass/copper sheet (ground plane), copper tape, SMA bulkhead, 3× M3×14, 1/4" nut, ASA prints (former + reflector + ball-head base + feed gauge)	one fixed beam; ball-head mount so elevation is set in the field	~10–15
Gas discharge tube or λ/4 shorted stub at the VRX input	static from wind/rain on the wire kills the frontend otherwise	~3
HDMI cable + public-viewing TV/monitor	the whole point	—

Interim/comparison station (store-bought, superseded as doctrine): TrueRC X²-AIR MK II patch (nominal 13 dBic, budget ~10, ~€60) · Lumenier Double AXII 2 LR (~4.7 dBic, ~€30) · TrueRC Matchstick Carbon Long (~1.9 dBic, €29.90). Kept for the measured A/B against the helices.

5 · Tools & measurement (staged — bench first)

item	≈ €	stage
Multimeter	~25	now — polarity check is a hard gate before first power
Balance charger 3S (+ XT60→XT30 adapter)	~40	now
K-type probe thermometer or IR thermometer	10–20	thermal A/B test (see MEASURE.md)
VNA covering 5.8 GHz (LiteVNA class — a NanoVNA-H does not reach the band)	~120	before trusting any antenna RF claim (sender clamp S11, helix SWR)

6 · Alternatives (with dims)

Every part below is a real, buyable component with a verifiable published dimension (or an honest "dims unpublished" where the maker only ships CAD). "Fits as-is" means it drops into the current case concept; "fits with note X" means it works but changes something you must account for. Wall thickness is never traded for volume — see the wall-thickness doctrine.

6.1 · VTX alternatives (core: Freestyle V2 = 29.2 × 30 × 14.1 mm, U.FL, 20×20 M2)

part	L×W×H	interface	fit
HDZero Freestyle V1 (30×30) — the backup unit on hand	40 × 42 × 10 mm, 28 g	U.FL, 30×30 M3 mount	fits with rework: larger footprint (40×42 vs 29.2×30) but thinner (10 vs 14.1) → needs a wider, shallower VTX bay and a 30×30 M3 boss pattern instead of 20×20 M2. Same 1 W class, same U.FL-once rule.
HDZero Race V3	28 × 32 × 5 mm, 5.5 g	U.FL, 20×20 M2 mount	fits with note: smaller and far thinner than the V2 (frees bay depth), 20×20 M2 boss pattern matches. But max 200 mW, not 1 W (4–12 V input, no 6S) → this is a link-budget downgrade, not a like-for-like swap — only for a short-range/low-power build.

6.2 · Camera alternatives (core: Nano90 = 14 × 18.5 × 19 mm, MIPI 20-pin)

part	L×W×H	interface	fit
HDZero Nano V3	14 × 16 × 14 mm, 2.2 g	MIPI 20-pin	fits as-is — nano-class body, essentially interchangeable with the Nano90 in the same clamp; Starlight low-light sensor is a bonus.
HDZero Micro V2	19 × 19 × 21 mm, 8.5 g	MIPI, 19×19 mount	requires camera-bay rework — the 19 mm square micro body does not fit the ~15 mm nano clamp; you would re-cut the camera bay for a 19×19 front mount.

6.3 · Battery alternatives — rule: ≤ 60 × 30 × 23 mm fits the bay; a shorter pack = more XT30 room

Core (850 flight unit): Tattu R-Line 3S 850 = 60 × 30 × 23 mm datasheet (measured 58 × 30 × 22 — the measured pack governs the bay), XT30. All 3S / XT30. Long-type "pencil" packs (≈ 72–74 mm) exceed the 60 mm bay length — do not force them. The mid and Mini 300 bays are sized around the Tattu 3S 300 mAh HV (measured 45 × 17.5 × 15.3) — the 850-class packs do not fit those two.

part	L×W×H	interface	fit
Tattu R-Line 3S 450 (compact)	45 × 24 × 21 mm	XT30 + JST-XH	fits as-is — 15 mm shorter than the 850 → generous XT30 slack; shortest airtime.
GNB/Gaoneng 3S 550 (standard)	58 × 31 × 17 mm	XT30 + JST-XH	fits with note: length/height fine, width 31 mm is ~1 mm over the 30 mm bay → snug; rely on the mandatory foam preload, don't over-compress.
CNHL Pizza 3S 600	74 × 12 × 24 mm	XT30	does not fit as-is — 74 mm length exceeds the 60 mm bay by 14 mm; listed only to illustrate the rule (long-type packs are out).

6.4 · Antenna alternatives (RHCP omni; core: Lumenier AXII 2 = Ø17.5 × 73 mm, SMA)

The captive-antenna coax clamp leaves a ~2.9 mm gap — that grips the thin coax cable, not a molded antenna head. Any SMA omni below swaps at the SMA joint exactly like the AXII 2; only the coax that runs to the clamp matters for the gap.

part	Ø × L	interface	fit
Foxeer Lollipop 4 Plus	head Ø15 × ~60 mm, 7.3 g, 2.6 dBic	SMA (RHCP)	fits with note: swaps at SMA like the AXII 2; the Ø15 molded head will not pass the 2.9 mm coax clamp — clamp the thin coax/SMA base, never the head. Shorter than the AXII 2.
TrueRC Singularity 5.8 SMA	head Ø11.8 × 8.2 mm, overall ~120 mm (length varies), 1.9 dBic stubby option	SMA (RHCP)	fits as-is — smallest CP head on the market; its thin flexible coax (~Ø1.1) actually suits the 2.9 mm clamp. Lower gain than the AXII 2 — a size/gain trade.

6.5 · Switch alternatives (core: 12 mm latching, 2 A)

part	dims	interface	fit
12 mm anti-vandal latching (Langir / APIELE / RJS class)	Ø12 mm thread, 12.2 mm panel cutout, body ~28.7 mm long (excl. terminals), panel 1–11 mm	pre-wired or solder-tag	fits as-is — identical 12 mm dimensional family, same panel cutout. ⚠ Verify current rating ≥ 2 A: many 12 mm latching switches are rated only 1–2 A, and momentary-only variants exist — the + line carries ~1.3 A continuous, so a sub-2 A or momentary part is unsafe/wrong.

6.6 · Heat-set insert alternatives (core: our bosses = Ø4.6 × 8 mm holes for a Ø5 × 6 insert)

part	OD × length	recommended hole	fit
ruthex RX-M3×5.7	length 5.7 mm; OD not published on the product page (CAD download only) — M3×5.7 class is smaller than our Ø5	Ø4.0 mm (per maker)	fits with rework — drill the bosses to the maker's hole (Ø4.0), not our Ø4.6; an oversized hole lets the insert spin.
CNC Kitchen M3×5.7	length 5.7 mm; OD per maker CAD (M3-standard)	Ø4.0–4.2 mm (per maker)	fits with rework — same story: match the boss hole to CNC Kitchen's 4.0–4.2 mm spec, not our Ø4.6. Blind hole ≈ 1 mm deeper than the insert.

Rule: a different insert = a different pilot hole. Always drill to the insert maker's spec, not to our Ø4.6 (which is sized for the Ø5 × 6 insert).

6.7 · Wago alternative (core: 221-412, 2-conductor lever nut)

part	L×W×H	conductors	fit
Wago 221-2411 (inline splice)	35.5 × 8.1 × 8.9 mm, 0.2–4 mm²	2, feed-through (in one end, out the other)	no direct 1:1 substitute — different topology. The 221-2411 is a straight inline joiner (slim, wires enter opposite ends), handy where the + line runs end-to-end; the 221-412 is the general junction block. Keep the 221-412 for the main +/− joins; use the 2411 only for a clean inline splice.

Sources (§6)

• HDZero Freestyle V1 VTX — docs · Freestyle 30×30 listing (40×42×10, 28 g, 30×30 M3)
• HDZero Race V3 VTX — docs (28×32×5, 5.5 g, 25–200 mW, 20×20) · Race V3 review — Oscar Liang
• HDZero Nano V3 camera — docs (14×16×14, 2.2 g)
• HDZero Micro V2 camera (19×19×21, 8.5 g, 19×19 mount)
• Tattu R-Line 3S 450 (compact) — genstattu · GNB 3S 550 standard (58×31×17) · CNHL Pizza 3S 600 (74×12×24)
• Foxeer Lollipop 4 Plus (2.6 dBic, SMA) · TrueRC Singularity 5.8 SMA (head Ø11.8×8.2)
• 12 mm anti-vandal latching switch — dimensional family · 12 mm switch panel/thread data — APIELE
• ruthex RX-M3×5.7 insert (length 5.7 mm, CAD only) · CNC Kitchen M3×5.7 + hole guide
• Wago 221-2411 inline splice (35.5×8.1×8.9)

Order-log reality notes (kept, because they will bite you too)

• The VTX kit was in stock at n-Factory when ordered; two other shops 404'd the same week.
• Buy the patch in the connector variant that matches your pigtail — the order log caught an RP-SMA/SMA mismatch at checkout.
• HDZero receivers churn: BoxPro was sold out at one shop; a used HDZero goggle/VRX from the classifieds is the cheapest first picture. Analog goggles cannot receive HDZero at all.
• Sender hardware total (without receiver): ~€ 410–450 as ordered.