Every so often a new product appears on the FPV scene without all the hype and fanfare which often precedes such events. The UHF Repeater from fpvlongrange.com is just such a product. The UHF Repeater is something which although the market may not have been crying out for it, now that it’s here it opens up several new and exciting possibilities.
Although referred to by the manufacturer (and throughout this preview) as a ‘UHF Repeater’, I’m not sure this is technically the best name for it. The UHF Repeater isn’t actually a repeater as it doesn’t re-transmit anything, instead it allows you to create a UHF repeater if you are already in possession of one of the many long range UHF control systems on the market e.g. DragonLink, EzUHF, TSLRS, ChainLink, RangeLink.
The way the UHF Repeater executes this is actually very simple. It accepts the standard servo outputs from any normal r/c receiver (35MHz, 72MHz, 2.4GHz) and combines these into a single PPM stream compatible with your long range UHF transmitter. And in a nutshell, that’s it!
First things first however, why would you need a UHF Repeater? After all, people are flying long range fine without one? True, for most people the UHF Repeater from fpvlongrange.com will not be a ‘must have’ item, but once you’ve been flying long range for a while, you may find some of the new opportunities this product presents, appealing. The first of these detailed on the list below however is definitely one those looking to get into long range FPV might find of most interest.
- The ability to make any UHF TX system compatible with any radio; it eliminates that recurring question “How do I connect my Spektrum/Futaba/Hitec radio to my EzUHF/DragonLink/TSLRS etc”. With this unit, gone too is the potential requirement to remove the back from your radio and hunt down that elusive PPM single. If you have a working r/c TX and RX (no matter what vintage or manufacturer), then by using the UHF Repeater from fpvlongrange.com it is instantly compatible with any of the long range UHF transmitters on the market today.
- For optimum long range control, you naturally want to ensure your UHF TX antenna is in an optimum location, which probably isn’t by your side. The UHF Repeater allows you to place your UHF TX in the best possible location for your surroundings (e.g. high up and/or away from local obstructions) regardless of where you are standing, ensuring unrestricted performance.
- Some people enjoy the idea of being able to sit in their home or car while flying FPV. The barrier this presents around your UHF TX naturally isn’t conducive to good performance, but by placing the UHF Repeater on the roof while you sit inside, this problem is eliminated.
- Many people strap their UHF TX to the back of their radio and either fly with this combination swinging from their neck, or recognize the potential consequences of this and stand very rigidly to ensure their UHF TX antenna remains upright. By using the UHF Repeater you no longer have to concern yourself with the orientation of your UHF TX antenna. You can recline back in a chair, safe in the knowledge that your UHF TX is upright a few (or several hundred) feet away.
- In enables you to put serious distance between your UHF TX and your video RX equipment. High power UHF transmitters can have an adverse effect on the sensitivity of your video RX. Separating your UHF TX from your video RX will help to minimize this.
- One of the most interesting things the UHF Repeater enables you to do, is to control different aspects of your plane from different transmitters. Since the UHF Repeater simply merges the servo signals into a single stream and does not care where they came from, you could have one transmitter controlling the flight elements of your plane and another for the camera operator.
So, what’s it like? Well, what’s immediately obvious is unlike many products designed for the FPV market, this one has a real commercial/professional feel, opposed to the frequent home-brew ‘shrink wrapped’ look. The electronics are potted in a custom machined-aluminium housing keeping them away from prying eyes and tampering fingers, while at the same time giving it an industrial ‘monolithic’ feel. There are no screws to undo here. It’s nice!
The UHF Repeater supports up to 12-channels and at one end resides 12 blue servo leads to connect to the output of your standard r/c receiver. The first servo lead also carries the +5V to power your receiver, but don’t try to drive any servos from it. There is sufficient power for your receiver, but no more. Whatever you plug into Ch-1 on the UHF Repeater will ultimately come out of Ch-1 on your UHF RX. Ch-2 on the UHF Repeater will come out of Ch-2 on your UHF RX and so on. It’s very straight forward.
At the other end of the UHF Repeater is a blue power LED, 2 power wires terminated with a JST connector (3S lipo compatible), 3 wires with the PPM output for your chosen UHF TX and an MPX connector for firmware updates NB: I’m not sure the initial logic behind choosing an MPX connector for firmware updates, but fpvlongrange.com have said they will amend this. With regards to what capacity battery you should use, I would suggest a minimum of 1000mAh. The UHF Repeater draws negligible power itself, but you should budget around 500mAh being required by your UHF TX.
Once everything is connected and powered up, it becomes completely transpire to you in operation and with my DragonLink TX and RX, it simply worked ‘out the box’.
Below is a demo of the UHF Repeater in operation. Here it’s wired up to the outputs from two different 2.4GHz receivers simultaneously, a Futaba and a Spektrum. Who would have thought you’d ever see these unlikely pair teaming up, eh?! Although the two servos are both connected to the same UHF RX, one is being controlled by a Spektrum DX7 and the other a Futaba 8FG.
One potential concern of using such a device would be if it added any delay to your control. The UHF Repeater does add some delay, but quite if this would present any consequence when flying long range, or even be perceivable, I largely doubt.
The below videos compare signal delays between a conventional set-up and one using the UHF Repeater.
Futaba -> UHF TX – > UHF RX
Futaba RX -> UHF Repeater -> UHF TX – > UHF RX
By stepping through the second video frame-by-frame, there appears to be a 5 to 6 frame difference between the trace movements, which would equate to around a 175ms delay.
Due to other commitments (not least 2 new plane builds), I’ve yet to do a flight test with the UHF Repeater, but I will do very soon and from what I’ve seen of it so far, I’m looking forward to it. As mentioned at the start, this product may not be for everyone, but it’s well engineered and once you understand the potential, you realise it has a definite place in our hobby.