Is this possibly the most popular 1.3GHz VTX for long range flying on a fixed wing and plane? Let’s check out the 1.3GHz 400mW VTX from ReadyMadeRC.
Where to Buy?
Many thanks to ReadyMadeRC for sending the VTX in for testing! You can buy it from:
Why 1.3GHz? Why 400mW?
The low frequency of 1.3GHz has better signal penetration ability than 5.8GHz, and therefore more suited for long range FPV. There are pro’s and con’s using 1.3GHz vs 5.8Ghz as discussed in this article, so I won’t repeat here.
You don’t really need a lot of power to fly long range on 1.3GHz. According to an unverified claim, 15 miles was achieved on 400mW even without breakup (using Mad Mushroom antenna on VTX, Pepperbox antenna on VRX). What?! 15 miles isn’t enough? Have you even thought about the amount of walking if you crash? :D
You could certain use higher power VTX, but there is a higher chance causing interference to other components, e.g. your radio receiver and GPS. It’s important to use just the right amount of power for what you need. Using more than you need can actually be bad when it comes to VTX.
There are two versions you can pick depends on your region: US and International (for the rest of the world). The only difference I can see in the specs is just the channels they support. Oh, and the color of the case too.
The US version is green, and the available channels are:
- 9: 1280MHz
- d: 1258MHz
The International version is blue, and the available channels are:
The one I am reviewing is the International version. It’s important that you understand which one you are getting, and that your receiver has the matching channels.
Looking for 1.3GHz video receiver? This is a good one: http://bit.ly/rmrc-1-3ghz-receiver.
In the package you can find the transmitter, a dipole antenna, and AV cable as shown:
The weight I measured is much lighter than advertised:
- VTX Weight: 58.1g
- Antenna Weight: 17.3g
It takes DC 12V as power (okay to be powered by a 3S LiPo directly), and current consumption is around 0.7A.
It uses SMA antenna connector. There is button next to the SMA, which is used to change channel. That’s about it, as simple as it can get :)
The RMRC 1.3GHz 400mW VTX comes with a huge blue heatsink case. It can be removed for a lighter and smaller form factor.
However if you do remove the heatsink/case, make sure you have good airflow to the VTX to avoid overheating.
To remove the case, simply take off the four screws on each side. You will also need to peel off the digit display protector with a slot screw driver. And the VTX slides right out.
The weight saving is massive!
- Weight without case and antenna: 22.3g (from 58.1g)
- Weight without case, with antenna: 39.5g (from 85.4g)
The 1.3GHz dipole antenna is pretty big and heavy, that’s why you don’t see people using 1.3GHz in Mini Quad.
I tested the RMRC 1.3GHz 400mW VTX with the ImmersionRC RF power meter V2. Every measurement was taken 10 seconds after the VTX was powered on, and the VTX was allowed enough time to cool down before the next measurement.
The results suggests this is more of a 300mW VTX rather than the specified 400mW. But still, 300mW should give you some serious range on 1.3GHz as long as you are using the right antennas :)