HobbyKing.com New Products Flash Sale

TrueRC Antennas for FPV Flying - Review

Using the right antennas for your style of flying is an important (and often overlooked) aspect of setting up a great performing fpv system.

Splash

Introduction

Product:TrueRC FPV Antennas
Fan Price:$45
Horizon Price:$75
Crosshair Price:$75
Available from:www.truerc.net

Using the right antennas for your style of flying is an important (and often overlooked) aspect of setting up a great performing fpv system. Up until a few years ago, linearly polarized (lp) antennas were the only choice available commercially. With proper setup and adherance to the laws that governed their performance, you could get exceptional distance from linearly polarized antennas. But, as most fpv pilots have experienced first hand, lp antennas are susceptable to multi-pathing as the incoming signal reflects off objects and hits the antenna from multiple angles, causing video distortion and at worst, cancelling out the signal entirely.

But in recent years, a small group of dedicated hobbyists began experimenting with existing circular polarization technology (cp) and applying it to fpv platforms. CP antennas shrug off the multi-pathing issues that have plagued lp antennas, and allow for a bit of leeway with regards to flight location and antenna placement.

In this review we'll explore a few different cp antennas from Hugo at TrueRC.net. The first antenna is a circularly polarized omni called the Fan. The Fan is designed for general flying at close to medium distances. The second antenna, designed for long range multicopter and ground applications, is a combination of two fans called the Horizon. The third antenna we will test is a long range cp directional called a crosshair. The Fan design was developed by Hugo at TrueRC, while the crosshair was a joint development between IBCrazy and Hugo. The frequency of choice in this review is 1.2GHz. Now, let's take a closer look at these antennas.

The Fan


Product:TrueRC Fan
Price (usd):$45
Gain:0.9 dbic
SWR:<1.2.:1 (Tuned for 1258 & 1280Mhz)
Polarization:RHCP
Connector:straight or angled sma
Length:6, 8, 10, 12 in.
Direct link:Click Here

The Fan is a circular-polarized omni antenna with five lobes. It's designed as a ground-based receiver antenna, but it's equally at home on a transmitter. The general rule of thumb is to place the antenna with the most lobes on the receiver. This is due to the increased multipath rejection associated with the antenna with the higher number of lobes, and the higher gain on the antenna with the lower number of lobes. Additionally, the inherent drag of the five lobe Fan makes it more suitable on the ground.

If you're flying a three lobe Windmill (available here) on your aircraft, pointing a lobe forward will yeild the best signal on the return flight. However, this assumes you are flying a standard outbound and return leg; if you are exploring your airspace at average distances from your receiver antenna or flying a multicopter, the fan can be used as a transmitter antenna quite effectively.

I decided to install the Fan on a Hoverthings FLIP fpv quadcopter, since I will be flying generally closer to my ground station than typical fixed wing platforms, and I'll be using the Horizon antenna on the receiver. The Fan comes in 6, 8, 10, and 12-inch lengths, and the white plastic tube between the SMA connector and antenna is rigid but easily bendable with a little heat. I used a 90-degree connector in lieu of bending it.

The Fan has proven to be a great transmitter antenna on my FLIP quad. While flying around the local construction site, I was able to go between heavy earth moving equipment and behind dirt hills with very little multipath interference showing up. The only downside I can think of for the fan is that it's delicate. True, most omni-directional antennas are also delicate, but some use thicker wires on the lobes and large globs of hot glue to keep everything together. The Fan uses very precise solder joints and thin wire. In the event of a roll over into the ground, I'm afraid it wouldn't have much of a chance for survival. However, that issue is moot if you use the Fan on your ground station receiver.

The Horizon


Product:TrueRC Horizon
Price (usd):$75
Gain:4.5 dbic
SWR:<1.3.:1 (Tuned for 1258 & 1280Mhz)
Polarization:RHCP
Connector:straight sma
Length:12" extension
Direct link:Click Here

The Horizon is a long range omni-directional antenna that's designed specifically for your ground receiver. It consists of two horizontally opposed Fan antennas that produce a respectable 4.5 dbic of gain. But there's a lot more that goes into building a Horizon than just vertically stacking two cp omnis. You'll notice that one antenna has a longer distance between it and the point where the two antennas meet. By keeping one coax shorter than the other, it gives an extra 1/2 wave so the antenna signals meet at the same time. While chatting with Hugo about his design, he offered me this analogy: Like two men paddling in a boat, they need to paddle in synch. In this case, one guy is facing forward and the other backward (one antenna face up and the other down). In order to paddle straight, the two men need to paddle in opposite timing.

The Horizon doesn't come with any brackets for mounting, so you'll need to use some good old-fashioned ingenuity to securely mount it. In my case, I zip-tied the antenna to a fiberglass rod, and then attached the rod to the receiver. Next, I built a wood stand with magnetic tape of the base. Since I mostly fly from the back of my SUV, the magnetic mount can be easily fixed to the roof and the antenna is given a clear 360-degree unobstructed view.

The Crosshair


Product:TrueRC Crosshair
Price (usd):$75
Size10" x 10"
Gain:10 dbic
Beam width:65 degrees
Polarization:RHCP
Connector:straight sma
Direct link:Click Here

The crosshair is a cp long-range directional antenna developed by Hugo at TrueRC and IBCrazy at Video Aerial Systems. It's designed for long-range missions, but with its 65-degree beam width, is also a good choice for general flying at a field or within a boundary. The Crosshair, as the name implies, features four (4) elements in an X configuration. The advantages of the crosshair when compared to a circularly-polarized helical antenna, are increased efficiency at around 98%, and is precisely tuned to 1280mhz. The Crosshair's video signal, however, does drop off quickly if you get outside of its beam area.

Like the Horizon antenna, the Crosshair does not come with any mounting options. In my case, I epoxied a piece of lite-ply to the back of the antenna and drilled it for my Manfrotto tripod attachment.

My initial tests have proven that the Crosshair performs very well, if not better than my 9.5 dbic helical antenna. I stretched the legs on my Bixler II with a 2000mAH lipo and had a very solid link at 2.5 miles out, and that's with Atlanta's higher-than-usual noise floor. As I stated above, the Crosshair did loose video signal quickly when I flew behind it while setting up for landing. The Crosshair paired with an antenna tracker would be a deadly combo for all types of flying.

Crosshair Video

Bixler 2 FPV Flight (8 min 22 sec)

Conclusion

With the multitude of cp omni and directional antennas on the market, you definitely have a choice with regards to picking the right antenna (and manufacturer) for the mission at hand. But judging by the construction and field testing results of the antennas in this review, I would put TrueRC among the top manufacturers currently offering fpv antennas. The elements and lobes are precise, and the performance of each antenna is tuned well for the given frequency.

Pluses

  • High quality build construction
  • Plastic cover on the Crosshair keeps the elements safe from moisture and impact.

Minuses

  • No tripod/tracker adapter on the Crosshair; You'll need to construct your own.

Credits

Thanks to Hugo at TrueRC.com for allowing me to test his antennas.

Last edited by Matt Gunn; Mar 27, 2013 at 09:33 AM..

Discussion

Reply
Thread Tools
Old Mar 29, 2013, 08:16 PM
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,186 Posts
Update:
After completing the review, Hugo at TrueRC announced he will be changing the center section of the Omni antennas for better durability. Picture of the new design below.
Matt
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Last edited by Matt Gunn; Mar 30, 2013 at 09:10 AM.
Reply With Quote
Old Mar 30, 2013, 09:17 AM
Registered User
Ireland
Joined Apr 2001
4,032 Posts
Could you specify the test setup used to measure the performance of the different antenna?
Things missing are SWR measurements and spectrum analyser readings to verify outside influences during range testing.
How was the transmitting power monitored during testing?

Thanks
cmulder is offline Find More Posts by cmulder
Reply With Quote
Old Mar 30, 2013, 09:34 AM
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,186 Posts
Unfortunately, I don't have a spectrum analyzer.

Standing wave radio numbers are listed in the spec sheet boxes next to each antenna section, except the crosshair which was not listed. Maybe Hugo can chime in with the SWR for the crosshair.

Matt
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Latest blog entry: Bill Hempel Xtreme Decathlon
Reply With Quote
Old Mar 30, 2013, 12:23 PM
Registered User
Ireland
Joined Apr 2001
4,032 Posts
Testing and the resulting reviews should do all possible to eliminate subjective observations.
Your review is a good start but incomplete and i like to challenge you and others to develop testing standards and guidelines.
Only then different tests and products can be compared one to one allowing the reader to make a informed choice what is the best for the intended application of the item.
cmulder is offline Find More Posts by cmulder
Reply With Quote
Old Mar 30, 2013, 12:59 PM
RCGroups Editor
Matt Gunn's Avatar
United States, OH, Parma
Joined Jul 2009
5,186 Posts
Thanks, I appreciate the feedback.
Matt Gunn is online now Find More Posts by Matt Gunn
RCG Plus Member
Latest blog entry: Bill Hempel Xtreme Decathlon
Reply With Quote
Old Mar 30, 2013, 01:27 PM
Registered User
Hugeone's Avatar
Canada,Quebec
Joined Jan 2005
2,065 Posts
I attached the SWR measurements of both crosshair and fan.

One testing approach that I like a lot is the 1mW test. It have been put forward by Old Man Mike. Simply, you install attenuators on your Vtx until you have 1mW left at output and go FPVing. The stacked fan took me one mile on 1mW, the Gatling reached 3.6miles. Unfortunately I do not have this data for the crosshair.

-Hugo
Hugeone is offline Find More Posts by Hugeone
Reply With Quote
Old Mar 30, 2013, 02:14 PM
Registered User
Ireland
Joined Apr 2001
4,032 Posts
Hugo the last graph is exactly the kind of data that should be standard in rf reviews.
Especially since it also shows the equipment used so others can replicate the measurements with different antenna so we can compare how they perform.
cmulder is offline Find More Posts by cmulder
Reply With Quote
Old Mar 30, 2013, 02:19 PM
Registered User
Ireland
Joined Apr 2001
4,032 Posts
Regarding the one mW test ; i agree with the intention but it does not eliminate outside influences.
For example ; does the aircraft the antenna is mounted on influence the radiation pattern ?
Other things i do not know but atmospheric influences also might influence the result so things like temperature and humidity could be useful data.
cmulder is offline Find More Posts by cmulder
Reply With Quote
Old Mar 30, 2013, 08:10 PM
BEOWULF
North vancouver, B.C. Canada
Joined Apr 2008
18,833 Posts
I mount fan tx antenna above cg point aprox
About 4 inches up

That plastic white rigid tube can be bent to make install easy with video tx inside plane

It works surprisingly well even with wings that are carbon sheeted and sparred

I find only small null directly under plane
There are no other areas that cause poor video

I ask Hugo for most dirrectional video tx antenna to go with fan
But find his patch video rx antenna to be not dirrectional at all
At 10 km away and way up very little turning of video rx it needed
All angles basically on the plane at far away are clear as well

I bring along in ground station a yagi that is high dirrectional to use if I ever need to do fox hunt and ground search for lost plane

Recently I order 3 more fan video tx antenna from Hugo because they seem to be very well designed

Not only good video but very surprisingly hangar rash and crash resistant

I thought copper antenna would bend easy ans stay bent
But fan antenna like spring and not bend

That white tube also really absorbs the rash antennas can get

My complaint is centre wire holding top of fan up is weak point and could be one guage thicker
As it bends and stays bent
Unless you bend it back after landing
David22 is online now Find More Posts by David22
Reply With Quote
Old Apr 01, 2013, 09:37 AM
Registered User
M4d_D's Avatar
Joined Dec 2006
845 Posts
hi,
what polarization do these antennas have ? im just thinking about putting a horizon and a crosshair on my receiver and using it with an encased transmitter antenna like the ones from immersion rc
does anyone know if that might work regarding the different shapes and especially regarding the polarization ?

cheers
M4d_D is offline Find More Posts by M4d_D
Reply With Quote
Old Apr 01, 2013, 02:03 PM
Registered User
Hugeone's Avatar
Canada,Quebec
Joined Jan 2005
2,065 Posts
They are RHCP and therefore work with all others CP antennas sold that I know of.

-Hugo
Hugeone is offline Find More Posts by Hugeone
Reply With Quote
Old Apr 05, 2013, 08:23 PM
KB3CJU
Spinjammer's Avatar
United States, MD, Baltimore
Joined Apr 2013
96 Posts
We also have the Field fox and several 80K Agilent Network Analyzers at work and Return
Loss expressed in negative db is the more current way to measure this because it has better resolution for small values of reflected wave.

Your antenna looks really good!

I just made a 1280 MHz cloverleaf LHCP antenna and was able to tune it to a value of over -16 db

Coincidentally we do wireless HD video, audio and data at work for sports a lot on 1.5 GHz
Spinjammer is offline Find More Posts by Spinjammer
Reply With Quote
Old Apr 05, 2013, 10:37 PM
Registered User
Hugeone's Avatar
Canada,Quebec
Joined Jan 2005
2,065 Posts
I normally measure in return loss, but for the post I switched to SWR as it is the what we most commonly see here. The antennas measured above had -29dB return loss.

-Hugo
Hugeone is offline Find More Posts by Hugeone
Reply With Quote
Old Apr 06, 2013, 01:25 PM
KB3CJU
Spinjammer's Avatar
United States, MD, Baltimore
Joined Apr 2013
96 Posts
That's what I figured

We RF guys need to use our tools and knowledge to help all we can
Old school VSWR meters are all most people can afford,
and can get you close enough

You schooled me, I didn't know the FF would do VSWR !
Thanks
Spinjammer is offline Find More Posts by Spinjammer
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Article HobbyKing Bixler II FPV Review Matt Gunn FPV Aircraft 56 Jun 27, 2014 11:01 PM
Wanted Antenna for 5.8GHz FPV 16dBi Directional HEATEDHAT FPV Equipment (FS/W) 3 Feb 13, 2014 05:04 AM
Article Foam-Tec Wingthing2 ARF Flying Wing Review DismayingObservation Flying Wings 6 Apr 16, 2013 10:16 PM
Discussion Please review my FPV quad wiring diagram schott1984 FPV Talk 9 Jan 04, 2013 10:38 PM
Mini-Review Review: TrueRC Hard Cased LiPos 5000mAh 2S 7.4V w/ TrueRC LVC w/ e-Station BC-6 rawfuls Off-road Cars 1 Nov 17, 2008 01:51 AM