Not getting enough FPV range on 5.8GHz? This guide will explain the many aspects of using 1.2GHz – 1.3GHz video transmitters (VTX) and receivers (VRX) to get longer range. It will take you through selecting gears and some tips for optimal performance.
1.2GHz vs. 1.3GHz
You hear people calling it 1.2GHz, sometimes 1.3GHz, so what’s the difference?
They are the same thing!
The channels available on 1.2-1.3GHz transmitters and receivers can range from 1080MHz to 1360MHz (1.08GHz and 1.36GHz), with 1256MHz and 1280MHz being probably the most popular channels. That’s because these are the only legal channels in the US, and many antennas are tuned for these frequencies.
Calling it 1.2GHz is just easy to remember, since that’s half of 2.4GHz – a popular frequency for radio control. But 1280MHz is in fact closer to 1.3GHz, so you can see why some people call it that as well.
A Good 1.3GHz Setup
I think this 400mW VTX and receiver from ReadyMadeRC are probably one of the best 1.3GHz FPV combo on the market.
- RMRC 1.2GHz Video Transmitter: https://oscarliang.com/rmrc-1-3ghz-400mw-vtx/
- RMRC 1.2GHz Video Receiver: http://bit.ly/2KTPEPb
However this is not cheap, and if you live outside of the US, prepare to pay more for the import tax too. If you are on a budget, check out this one on Banggood. It does exactly the same thing minus a few channels.
- Banggood 1.2GHz VTX and VRX Combo: http://bit.ly/2s2wkXz
As for antennas, the dipoles that they come with are fine for the most part. If you want extra range and reliability, check out these popular aftermarket antennas below.
- Pepperbox (VRX): http://bit.ly/2BPFH2y
- Patch Antenna (VRX): http://bit.ly/2BLMMju
- Mad Mushroom (VTX & VRX): http://bit.ly/2BR4Vxe
- VAS Blue Beam Clovers (VTX, VRX): http://bit.ly/2AllL6q
- Dragonlink Antenna (VTX): http://bit.ly/2QYxd20
Channels on 1.2GHz
Here are some common channels available for 1.2/1.3GHz band for FPV:
- 1280MHZ (US)
- 1258MHZ (US)
1.2GHz vs. 5.8GHz for FPV
You rarely see people using 1.2GHz on a mini quad, usually on larger long range planes and wings. Here is why:
- 1.2GHz uses huge and heavy antennas
- Very few options when it comes to VTX and VRX, the technology is old and lacks features compared to 5.8GHz
- Very strict regulations: license is required regardless power level in the USA and It’s illegal to use in many countries
- It can interfere with popular radio frequencies, such as 2.4GHz
- Lower video quality compared to 5.8Ghz because the lower frequency carries less data
But for those who do use 1.3GHz, they are only after two things: Long range and reliability! The lower frequency offers much better signal penetration through obstacles.
Before Buying, Ask Yourself…
Are you currently using a 5.8GHz setup? If so, have you already maxed out the capability of your 5.8Ghz setup?
My point is, avoid impulse-buying new gear if you still have room to grow in your current setup.
A 600mW VTX on 5.8Ghz with a good directional antenna on the receiver, should easily give you a few miles of range! (many achieved 10Km+, check Youtube). My personal best was flying with a 25mW VTX and 1Km out, so you can see there is clearly potential to 5.8Ghz for mid or even long range in open field :)
Here are some ideas what antennas to get for your 5.8GHz setup.
The key in achieving good range with 5.8GHz is maintaining line of sight between the transmitter and receiver antennas. Signal becomes extremely bad with obstacles, one little tree is all it takes to block your signal, and that’s where 1.3GHz comes into play.
What VTX Power Level?
1.3GHz VTX are still very primitive compared to those of 5.8GHz, the technology and products haven’t changed for years. They normally come with a huge heat sink, with a fixed output power that can’t be changed like the newest 5.8GHz VTX.
When you are just getting into 1.3GHz, there is no need to go crazy on VTX power. 200mW to 400mW is plenty to begin with. Based on reports from the community, a 400mW VTX is capable of doing 15 miles or more.
Going higher in VTX power without knowing what you are doing will probably do more harm than good. High power VTX could swamp your radio receiver, causing range issues long before your video gives up. It can even interfere with other components on your aircraft such as digital servos and GPS.
A successful flight with 1.2GHz FPV system is a combination of good setup, flying environment and antennas.
Interference from RC Frequency
As mentioned, 2.4GHz radio link can interfere with 1.2GHz video, therefore 433MHz or 900MHz (868MHz – 915MHz) is commonly used instead, such as Frsky R9M. And try to stay away from people flying on 2.4GHz.
1.3GHz is possible to get interference from 900MHz to some degree as well. It gets worse when you are transmitting high power on the TX module (e.g. 1W or higher). Here are some tips to help minimize interference.
Lower TX Power
First of all, do not switch to the maximum power if you don’t have to. I know the option is available and it’s tempting to use it, but it could do more harm than good sometimes.
200-250mW on your Crossfire/R9M in theory is enough for miles, and could probably out-range what your battery can do anyway on a quadcopter.
Make sure there is enough separation between your radio and video receiver on the ground. It’s impossible to say how far the separation must be, maybe 20 feet (6 meters), or even 50 feet (15 meters) it really depends on the actual setup and environment.
Check out “DIY 1.2GHz to 5.8GHz Relay“, it’s an easy way to increase separation without wires.
Leaving good separation between the video transmitter and radio receiver on the aircraft is equally important.
You can buy filters that are designed to block out unwanted frequency for your video transmitter or receiver. These can help reduce interference when separation of antennas are not possible/enough. However, take this as the last resort, as these filters can also cause signal power lost.
- This one helps reduce interference from 915MHz radio (notch filter)
- This one does the same but for 868MHz (notch filter)
- This one, and this one help reduce interference from 2.4GHz radio (low pass filter) – allows you to use 2.4GHz RC link and fly with people with 2.4GHz
Further Reading: What are notch filter and low pass filter? (different scenario but principle is the same)
Removing VRX Lid
The trick is removing the lid in the 1.3GHz VRX, which supposedly helps reduce interference.
It might sounds a bit strange, but it’s been proven to work many times to certain extend. It won’t cost you anything so it’s worth a shot when nothing else worked.
1.3GHz VTX Can Affect GPS
Another thing to beware of, is that 1.3GHz can affect GPS module on your RC model. Keep your VTX antenna away from your GPS module as far away as possible.
Use a Tripod
Since you are probably going to fly long range with 1.2GHz, you might want to get a tripod, or just a long pole to mount your video receiver and antenna on. The higher you can mount your video receiver antenna from the ground, the more reliable signal you are going to get.
If you know any other tips that I haven’t mentioned, feel free to share with us in the comment :)