We have been waiting a year if not two for the release of the NexWaveRF range of 2.4ghz transmitters and receivers; the transmitters started shipping last month, the goggle modules started shipping last week and the UNO (sealed) version started shipping today and ImmersionRC have announced that they will be offering an ‘Unfiltered’ (pro) version.
I bet you’re now thinking “Unfiltered? What the heck does that mean?” – Well when you make a receiver very sensitive not only is it sensitive to the frequencies its designed to receive it can also be affected by those that it is not meant to receive so the manufacturer will design it so that a filter is used to “clean” the received signal before it is amplified which means your UHF transmitter or even your mobile phone are not going to spew interference all over your video feed.
The problem is this filter can also reduce range because it reduces the gain of the receiver so ImmersionRC have decided to offer a version without the filter but this does mean you’ll need to keep your receiver well away from your RC radio and anything else that might cause interference.
The recently released Uno2400 comes in two versions, a standard version, and something that we call the ‘Unfiltered edition’. Bound to cause some confusion, but we have a good explanation
During the (2 year) development process for the Uno2400, we arrived at a happy place, a receiver module that was more sensitive than anything else on the market, with some cool GaAs*, pHEMT* technology in it’s very low noise front-end.
In it’s standalone edition, installed in the Uno2400, it worked a treat, but when the same module was used in an LCD Headset (a.k.a. The Goggles), the close proximity of the receiver antenna, to the high power UHF transmitter antenna, caused a nasty reduction in range.
To fix this, we squeezed a low-loss filter into the design before the amplifier, loosing a little gain, but eliminating all interference from UHF (and other) sources.
We still ended up with a ‘best in class’ receiver, but it didn’t feel right not to make the ‘unfiltered’ version available to FPVers who know to keep their UHF antenna away from their 2.4GHz receiver antenna, and would appreciate a higher (3-4dB) sensitivity.
Confused? Lets summarize:
– Standard Uno2400 – Extremely sensitive, best in class receiver, which tolerates extremely close UHF interference
– Unfiltered Uno2400 – Even more sensitive, still best in class, which needs some distance from the UHF Tx.
* GaAs = Gallium Arsenide, a cool technology for making chips.
* pHEMT = High-electron-mobility transistor… a fancy name for a technology used to make extremely low-noise amplifiers.