Mode names and figures follow current ExpressLRS docs (3.x/4.x). Sensitivity values come from the Signal Health page; if your Lua prints a different number next to the rate, trust the Lua.
A freestyle starting point
Oscar Liang's freestyle baseline is a sensible first flight config for a typical 5-inch:
| Setting | Value | Why |
|---|---|---|
| Packet rate | 250 Hz (LoRa) | Balance of latency and range for typical freestyle distances |
| Telem Ratio | Standard | Keeps roughly a few telemetry packets per second without hand-tuning after every rate change |
| Switch Mode | Wide | Enough AUX resolution for modes, VTX, and camera control |
| TX power | 100-250 mW, Dynamic Power on | Enough for park and field freestyle; dynamic power uses SNR from telemetry |
If the flight goes longer or the trees get denser, drop to 150 Hz or 50 Hz before you reach for more milliwatts. For race practice, 500 Hz LoRa or FLRC (F500 / F1000) is about cutting a millisecond off the loop when you save a near miss - most people cannot tell 150 Hz from 500 Hz by "feel" alone.
Never change packet rate while armed. A rate change forces a reconnect. Betaflight sees that as signal loss.
What packet rate actually buys you
Packet rate is simply how many control packets the TX tries to put on the air each second. Raise it and stick-to-motor delay falls. Lower it and each LoRa packet spends longer on the air with stronger coding, so sensitivity improves and the same milliwatts go further.
On 2.4 GHz you mainly choose among three families:
LoRa (normal modes) - 50, 150, 250 and 500 Hz, with Full Res options at 100 and 333 Hz. This is the freestyle and long-range set. Airtime is longer than FLRC, but weak signal and interference are handled better.
FLRC (F and D modes) - F500, F1000, plus DVDA variants D500 and D250. Shorter over-the-air time, lower latency, sensitivity around -104 dBm. That is worse than 250 Hz LoRa (-108 dBm) and well behind 50 Hz (-115 dBm). D500 sends each packet twice; D250 sends it four times. LQ holds up better in RF soup; latency rises a little. Racers care. Most freestyle packs stay on LoRa unless the flying site is hostile and range is secondary.
Full Res - 100 Hz Full and 333 Hz Full. Built for fixed-wing and anything that needs many full-resolution channels. A freestyle quad on Hybrid or Wide stays on the classic LoRa/FLRC list.
Approximate 2.4 GHz sensitivity limits from ExpressLRS Signal Health (ELRS 4.x RFMD table):
| Packet rate (Lua) | Modulation | Sensitivity limit |
|---|---|---|
| 50 Hz | LoRa | -115 dBm |
| 150 Hz | LoRa | -112 dBm |
| 250 Hz | LoRa | -108 dBm |
| 500 Hz | LoRa | -105 dBm |
| 333 Hz Full | LoRa | -105 dBm |
| F500 / F1000 / D250 / D500 | FLRC | -104 dBm |
Treat sensitivity as the floor. When RSSI dBm nears it, LQ can collapse quickly. Set the OSD alarm 5-10 dB above your rate's limit - at 250 Hz that is about -103 to -98 dBm for osd_rssi_dbm_alarm.
Hardware caps apply. Some built-in modules stop at 250 Hz. F1000 needs CRSF baud above 400000 and a recent EdgeTX; if the Lua packet counter wobbles or F1000 will not engage, fix baud and EdgeTX before chasing antennas.
Matching Betaflight to the rate
Betaflight feedforward is tuned around how often RC packets arrive. ExpressLRS asks you to load the RC Link preset for your packet rate: Presets tab, search ExpressLRS, pick the matching link preset or the closest lower one. Skip that and feedforward can look noisy even when RF is clean - twitchy tracking with a perfect LQ.
Change the Lua rate, then re-apply the matching preset (or check that smoothing still matches). Save a Configurator diff before you apply presets.
Telemetry ratio without the folklore
Telemetry ratio is how often the receiver gets an air slot to talk back.
1:8 means one telemetry packet for every eight control packets. 1:128 means one telem per 128 control packets. Bigger second number = rarer telemetry = more airtime left for sticks.
Two traps show up constantly:
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Packets per second scale with packet rate. 500 Hz at 1:128 still yields about 3.9 telem packets per second. 50 Hz at 1:128 yields about 0.4. Leave 1:128 stuck after you drop to 50 Hz and sensors plus Lua feel dead for no obvious RF reason.
-
Uplink and downlink are unequal. TX modules often run 100 mW-1 W. Many receivers send telem around 25 mW (some reach 100 mW). Full stick authority with Telemetry Lost on the radio is normal when the return path dies first. Dynamic Power reads SNR from telemetry; weak telem can park the TX at max power even when less would do.
Burst telemetry keeps link-stat packets arriving about every 512 ms and spends leftover telem slots on FC data and MSP. Official numbers at 250 Hz:
| Telem ratio | Telem packets/s | Bandwidth (no burst) |
|---|---|---|
| 1:128 | 2.0 | 39 bps |
| 1:64 | 3.9 | 78 bps |
| 1:32 | 7.8 | 156 bps |
| 1:16 | 15.6 | 312 bps |
| 1:8 | 31.2 | 625 bps |
| 1:2 | 125 | 2500 bps |
At 500 Hz each row roughly doubles. "Use 1:128 for racing" only stays sane when packet rate is high enough that you still get a few telem packets each second.
Standard, Disarmed, Off, and fixed ratios
Current Lua builds offer dynamic modes plus the old fixed ratios.
Standard (Std) - Chooses a recommended ratio for the selected packet rate, targeting about four telemetry packets per second on classic rates (about three on full-res). It became the default after newcomers left 1:128 in place across rate changes and drowned in telemetry warnings. For freestyle, use Standard unless you have a specific reason not to.
Disarmed (sometimes labelled Race) - Standard on the ground, telemetry off once armed. Control gets the whole link in the air; VTX Admin and Betaflight Lua still work before takeoff. It also pulls in the racer-oriented no-sync-on-arm behaviour. Pick it when you want zero telem airtime after arming and accept that Dynamic Power and in-flight sensors pause while armed.
Off / No telem - No return packets at all. Maximum stick airtime. You give up radio-side LQ/RSSI that need telem, Dynamic Power feedback, and FC sensors. Race-only territory.
Fixed 1:2 ... 1:128 - Manual. Use denser ratios (1:8, 1:4, 1:2) for fast MSP - Betaflight Lua, VTX tables - or when a slow packet rate still needs usable telem. Sparse ratios only make sense once you have done the packets-per-second maths above.
Telemetry Lost with healthy LQ and solid sticks: try Standard before you condemn the receiver. Oscar Liang calls out stuck high ratios as a frequent cause. Then check RX telem power and antenna placement; the return path is the weak half.
For radio-side configuration sessions, ExpressLRS suggests something like 200 Hz or 500 Hz with 1:2 and serial baud at least 400000 so Betaflight Lua stays usable. Restore freestyle rate and Standard before you walk to the pad.
Switch mode, arm channel, and why they sit next to rate
Hybrid and Wide work on the freestyle rates (50 Hz through F1000). Full Res switch options only show up on 100 Hz Full and 333 Hz Full.
Wide is the usual freestyle pick: AUX2-AUX8 at 64 positions (128 in some 3.x telem-ratio cases), and Wide also ships TX power to the OSD for Dynamic Power. Hybrid is coarser and a bit cheaper on switch airtime.
Arm on AUX1 (channel 5), ~1000 µs disarmed and ~2000 µs armed, unless you deliberately set ExpressLRS 4 alternate arming. AUX1 is in every packet. An arm switch on a round-robin AUX may wait several packets, and under loss you can fail to disarm. The Before First Flight page treats that as a safety rule.
Reading the link in the OSD
In Betaflight's Receiver tab, set RSSI Channel and RSSI_ADC to Disabled. In the OSD, enable Link Quality and RSSI dBm. Skip the old "RSSI Value" element unless unmodded DJI goggles force you to use it.
| What you see | Likely meaning |
|---|---|
| High LQ, strong RSSI dBm | Healthy link |
| High RSSI, falling LQ | Interference / collisions; power alone may not fix it |
| Low RSSI, still high LQ | Approaching range limit, or antenna issue if you are still close |
| Low LQ and low RSSI | Turn back; failsafe is close |
Start from osd_link_quality_alarm = 60. Put osd_rssi_dbm_alarm 5-10 dB above your rate's sensitivity. On EdgeTX, RF alerts use RQly; ExpressLRS suggests about 50% low and 20% critical.
LQ is whether packets arrive. RSSI dBm is how close you sit to the sensitivity cliff. You want both on screen.
Power, Dynamic Power, and freestyle range
Rate and power trade. At 50 Hz, 100 mW on 2.4 GHz LoRa can go further than most freestyle pilots will ever use. At 500 Hz or FLRC the same power covers less ground because sensitivity is worse. Inside a kilometre of open field, 100-250 mW at 250 Hz is enough for most people. EU LBT firmware tops out at 100 mW; pick rates with that ceiling in mind.
Dynamic Power moves output from SNR carried in telemetry, so it needs a live telem path. Disarmed/Race mode turns telem off when armed, so dynamic behaviour in the air is limited on purpose.
Antenna placement usually beats another 3 dB of power. A vertical RX antenna clear of carbon and the VTX often fixes more than a jump from 250 mW to 500 mW.
Practical recipes
Park / urban freestyle (default)
250 Hz LoRa, Standard telem, Wide switches, Dynamic Power, max 250 mW (100 mW on LBT). Betaflight ExpressLRS 250 Hz RC Link preset. Arm on AUX1.
Tree lines and longer freestyle
150 Hz or 50 Hz LoRa, Standard telem, same switch/power habits. Re-apply the matching RC Link preset. Lower the RSSI dBm alarm to match the new sensitivity.
Race practice on a freestyle quad
500 Hz LoRa, or F500/F1000 if your radio baud allows. Telem Ratio Standard or Disarmed. Accept less penetration; keep the quad closer. Confirm the Lua packet counter matches the selected rate (e.g. stable 0:500).
Bench / Lua configuration session
Temporarily 500 Hz (or 200 Hz) with 1:2 telem, baud ≥ 400000. Discover sensors on the radio telemetry page. When finished, restore freestyle rate and Standard before arming outdoors.
Telemetry Lost but sticks still work
Switch ratio to Standard; check RX antenna and telem power; remember downlink is weaker than uplink. Do not raise TX power as the first fix for a telem-only warning.
Checklist before you blame the hardware
- Packet rate matches how you fly (250 Hz freestyle baseline).
- Telem Ratio is Standard (or Disarmed if you knowingly want telem off when armed).
- Betaflight RC Link preset matches the rate.
- OSD shows LQ and RSSI dBm; alarms set from sensitivity.
- Arm on AUX1 unless you configured ELRS 4 alternate arming.
- No Lua rate changes while armed.
- Bench RSSI sanity check at 1 m and lowest TX power (about -40 to -25 dBm on healthy 2.4 GHz gear per ExpressLRS docs).
Nail that list and ExpressLRS fades into the background - sticks when you move them, telemetry when you glance down, and no Telemetry Lost loop on every punch-out.