frequencies?

[hellogoose]

Legal and illegal frequencies??? I live in Singapore so I did some research and found this link. I am very confused... Bands? SRD? ERP? can someone pls help me make sense of this, do I have to worry about it? Do I have to check if my tx uses the legal frequencies? Thanks!

 

[LitterBug]

Legal and illegal frequencies??? I live in Singapore so I did some research and found this link. I am very confused... Bands? SRD? ERP? can someone pls help me make sense of this, do I have to worry about it? Do I have to check if my tx uses the legal frequencies? Thanks!

What TX are you planning to use? Are there any RC groups in your area you could consult?

 

[bisco]

goverrnment regulators you can contact or search for regulations? ua-registration

 

[hellogoose]

What TX are you planning to use? Are there any RC groups in your area you could consult?

Fs i6, 2.408 - 2.475GHz AFHDS 2A???

 

[hellogoose]

goverrnment regulators you can contact or search for regulations? ua-registration

https://www.imda.gov.sg/-/media/imda/files/regulation-licensing-and-consultations/frameworks-and-policies/spectrum-management-and-coordination/spectrummgmthb.pdf

This is a government source, I just can't understand it

 

[Houndpup Rc]

Here, I got ChatGPT to write this up...Hope it helps! (And yes, you can use your FS-i6👍)



This guide explains radio frequency rules for RC and FPV in plain language. It is written for hobbyists, not lawyers, but reflects Singapore IMDA requirements accurately, with the most important compliance points clearly stated.

---

1. What is a “band”?​

A band is simply a range of radio frequencies.
Common bands used in RC and FPV:

• 2.4 GHz – RC control, Wi-Fi, Bluetooth
• 5.8 GHz – FPV video transmitters
• 900 MHz / 433 MHz – Long-range RC control systems

Different countries allow different bands and power limits. Singapore is strict, but well defined.

---

2. What does “SRD” actually mean?​

SRD = Short Range Device, but the name is misleading.
SRD is a regulatory category, not a distance limit.
It does not mean the device only works at short range.
SRD simply means:

• License-exempt equipment
• Operating in approved frequency bands
• Under defined power and emission limits

RC transmitters, FPV systems, wireless remotes, and sensors all fall under this category.
Modern systems like ELRS are legally SRDs even though they can fly many kilometers, because legality is based on how the signal is transmitted, not how far it goes.

---

3. What are ERP and EIRP?​

This is where most people get confused.
ERP / EIRP = how strong the signal actually is once it leaves the antenna.
It includes:

• Transmitter output power
• Antenna gain

Example:

• Transmitter set to 100 mW
• Antenna adds gain
• Final radiated power may be higher than 100 mW

Regulators limit EIRP/ERP, not just the transmitter setting.

---

4. Why Singapore’s rules look complicated​

IMDA publishes detailed tables covering:

• Frequency ranges
• Maximum allowed EIRP
• Device classifications
• Technical limits

This looks intimidating, but in practice:
Consumer RC and FPV equipment is already designed to comply, as long as you do not override limits or use non-standard bands.

---

5. Do hobby pilots really need to worry?​

Yes — but only a little.
You don’t need to study regulations. You only need to check:

1. Which frequency band you are using
2. That your power level is legal for Singapore

That’s it.

---

6. What is generally safe and legal for hobby use in Singapore?​

RC control links​

• 2.4 GHz – Safe, common, and universally accepted
• 900 MHz systems (ELRS/Crossfire) – Use with caution. Singapore’s general SRD rules reference the 920–925 MHz band, but IMDA’s UAS-specific guidance does not clearly list 900 MHz for drones. If used, firmware must be region-locked correctly and compliance is the pilot’s responsibility.
• 433 MHz – Technically legal, but capped at 10 mW ERP, which makes it impractical for RC flight and best avoided

FPV video​

• 5.8 GHz – Legal up to 100 mW EIRP
• 1.3 GHz – Generally not legal without licensing

---

What does “low VTX power” mean in Singapore?​

For Singapore, “low VTX power” means staying within IMDA’s unlicensed limit.
5.8 GHz FPV video power levels:

• 25 mW – Fully compliant, short range
• 100 mW – Maximum legal limit for unlicensed UAS use
• 200 mW and above – Exceeds the unlicensed limit in Singapore

Although 200 mW is considered “low” in some countries, it is not compliant in Singapore unless you have specific authorization.

---

7. How people accidentally break the rules​

Most issues happen when pilots:

• Set VTX power to 200 mW or higher
• Use the full US “915 MHz” band instead of Singapore-appropriate settings
• Assume “long-range” gear is legal by default
• Ignore firmware region settings

Normal hobby pilots using stock gear and sensible settings are not the enforcement target, but incorrect power or frequency settings can still be a violation.

---

8. Simple compliance checklist​

• Use 2.4 GHz for control and 5.8 GHz for video
• Keep 5.8 GHz VTX power at 100 mW or less
• Set firmware regions correctly (especially for 900 MHz systems)
• Avoid 433 MHz for RC control
• Do not modify transmitters or add amplifiers

---

Final clarification about SRD and long-range systems like ELRS​

Despite the name, SRD does not limit distance.
Regulations care about:

• Frequency band
• EIRP limits
• Emission compliance

Modern systems achieve long range through efficiency, not excessive power.
If frequency and power limits are respected, distance alone is not regulated by radio rules.

---

Important note: Line of Sight (LOS)​

LOS rules are not radio rules.

• IMDA regulates radio frequencies and power
• CAAS regulates flight operations

In Singapore, recreational RC and FPV flying is generally limited to Visual Line of Sight (VLOS) unless special authorization is obtained. FPV does not remove this requirement.
A radio link can be legal while the flight itself is not.

---

Important note: radio rules vs flight rules​

This guide covers radio frequency legality only (IMDA).
It does not cover:

• Where you are allowed to fly
• Altitude limits
• No-fly zones
• Aircraft weight rules

Those are handled separately by CAAS.

---

Bottom line​

• 2.4 GHz control + 5.8 GHz video at ≤ 100 mW is the safest default
• Long range capability does not equal permission to fly far
• Check your settings once, fly responsibly, and you’re fine

 

[hellogoose]

Here, I got ChatGPT to write this up...Hope it helps! (And yes, you can use your FS-i6👍)



This guide explains radio frequency rules for RC and FPV in plain language. It is written for hobbyists, not lawyers, but reflects Singapore IMDA requirements accurately, with the most important compliance points clearly stated.

---

1. What is a “band”?​

A band is simply a range of radio frequencies.
Common bands used in RC and FPV:

• 2.4 GHz – RC control, Wi-Fi, Bluetooth
• 5.8 GHz – FPV video transmitters
• 900 MHz / 433 MHz – Long-range RC control systems

Different countries allow different bands and power limits. Singapore is strict, but well defined.

---

2. What does “SRD” actually mean?​

SRD = Short Range Device, but the name is misleading.
SRD is a regulatory category, not a distance limit.
It does not mean the device only works at short range.
SRD simply means:

• License-exempt equipment
• Operating in approved frequency bands
• Under defined power and emission limits

RC transmitters, FPV systems, wireless remotes, and sensors all fall under this category.
Modern systems like ELRS are legally SRDs even though they can fly many kilometers, because legality is based on how the signal is transmitted, not how far it goes.

---

3. What are ERP and EIRP?​

This is where most people get confused.
ERP / EIRP = how strong the signal actually is once it leaves the antenna.
It includes:

• Transmitter output power
• Antenna gain

Example:

• Transmitter set to 100 mW
• Antenna adds gain
• Final radiated power may be higher than 100 mW

Regulators limit EIRP/ERP, not just the transmitter setting.

---

4. Why Singapore’s rules look complicated​

IMDA publishes detailed tables covering:

• Frequency ranges
• Maximum allowed EIRP
• Device classifications
• Technical limits

This looks intimidating, but in practice:
Consumer RC and FPV equipment is already designed to comply, as long as you do not override limits or use non-standard bands.

---

5. Do hobby pilots really need to worry?​

Yes — but only a little.
You don’t need to study regulations. You only need to check:

1. Which frequency band you are using
2. That your power level is legal for Singapore

That’s it.

---

6. What is generally safe and legal for hobby use in Singapore?​

RC control links​

• 2.4 GHz – Safe, common, and universally accepted
• 900 MHz systems (ELRS/Crossfire) – Use with caution. Singapore’s general SRD rules reference the 920–925 MHz band, but IMDA’s UAS-specific guidance does not clearly list 900 MHz for drones. If used, firmware must be region-locked correctly and compliance is the pilot’s responsibility.
• 433 MHz – Technically legal, but capped at 10 mW ERP, which makes it impractical for RC flight and best avoided

FPV video​

• 5.8 GHz – Legal up to 100 mW EIRP
• 1.3 GHz – Generally not legal without licensing

---

What does “low VTX power” mean in Singapore?​

For Singapore, “low VTX power” means staying within IMDA’s unlicensed limit.
5.8 GHz FPV video power levels:

• 25 mW – Fully compliant, short range
• 100 mW – Maximum legal limit for unlicensed UAS use
• 200 mW and above – Exceeds the unlicensed limit in Singapore

Although 200 mW is considered “low” in some countries, it is not compliant in Singapore unless you have specific authorization.

---

7. How people accidentally break the rules​

Most issues happen when pilots:

• Set VTX power to 200 mW or higher
• Use the full US “915 MHz” band instead of Singapore-appropriate settings
• Assume “long-range” gear is legal by default
• Ignore firmware region settings

Normal hobby pilots using stock gear and sensible settings are not the enforcement target, but incorrect power or frequency settings can still be a violation.

---

8. Simple compliance checklist​

• Use 2.4 GHz for control and 5.8 GHz for video
• Keep 5.8 GHz VTX power at 100 mW or less
• Set firmware regions correctly (especially for 900 MHz systems)
• Avoid 433 MHz for RC control
• Do not modify transmitters or add amplifiers

---

Final clarification about SRD and long-range systems like ELRS​

Despite the name, SRD does not limit distance.
Regulations care about:

• Frequency band
• EIRP limits
• Emission compliance

Modern systems achieve long range through efficiency, not excessive power.
If frequency and power limits are respected, distance alone is not regulated by radio rules.

---

Important note: Line of Sight (LOS)​

LOS rules are not radio rules.

• IMDA regulates radio frequencies and power
• CAAS regulates flight operations

In Singapore, recreational RC and FPV flying is generally limited to Visual Line of Sight (VLOS) unless special authorization is obtained. FPV does not remove this requirement.
A radio link can be legal while the flight itself is not.

---

Important note: radio rules vs flight rules​

This guide covers radio frequency legality only (IMDA).
It does not cover:

• Where you are allowed to fly
• Altitude limits
• No-fly zones
• Aircraft weight rules

Those are handled separately by CAAS.

---

Bottom line​

• 2.4 GHz control + 5.8 GHz video at ≤ 100 mW is the safest default
• Long range capability does not equal permission to fly far
• Check your settings once, fly responsibly, and you’re fine

thx!
how to find erp of tx?
what does "not specific SRD" mean?

 

[LitterBug]

Your best option may be to contact the radio manufacturer support for this help. They know their products and where they are certified to operate.

 

[hellogoose]

Your best option may be to contact the radio manufacturer support for this help. They know their products and where they are certified to operate.

It says <20 dBm on the website but dBm vs mw