Spektrum 2.4GHz modules and radio gear have become some of the
most innovative products to be introduced in RC in quite some time.
Racers and hobbyists around the world have adopted this breakthrough
technology at an amazing rate. From the time that the original modules
were made available to the general public, the response has been
largely positive, highlighted with the RC Innovation of the Year Award
from Radio Controlled Car Action Magazine. Like any new technology
though, there have been some questions about the performance— namely
the latency of a DSM signal vs. a standard FM or PCM signal.
Understanding Latency and DSM
Latency is the delay that occurs from the moment an input is given
at the transmitter (steering or throttle movement) to the moment that
the servo receives a pulse telling it to move. Most crystal-based radio
systems have a latency between 10–20 milliseconds. That’s only
.0010–.0020 of a second of latency.
Spektrum’s first DSM system added an additional 5.6m/s of latency
into the total system latency of a radio and its module. Again, we’re
speaking in terms of thousandths of a second here. While drivers around
the country used the original system and loved them, there were some
who said they could feel the additional latency in the system and felt
it was hampering their performance.
Listening to the Racers: The Pro Series is Born
As we’ve shown, 5.6m/s isn’t much. Still, some racers insisted they
could feel a slower reaction time when they equipped their radios with
Spektrum modules. In some instances, the latency could be compensated
for by either turning up throttle or steering exponential rates or by
using faster servos; others simply couldn’t make the adjustment.
Spektrum engineers immediately when to work to improve transmission
time while still maintaining a solid RF link for that locked-in feel.
Through testing and development with engineers and top racers such as
Travis
Amezcua,
E.J. Evans, John Adams, and Sonny Brown, it became possible to drop the
latency to only 3m/s while still maintaining a robust RF link. And so,
the Pro Series Spektrum equipment was born.
While they were at it, they incorporated a few other changes to the
Pro Series equipment. One included a new conformal coating to the
circuit boards inside the receivers to make them waterproof. Another
was the new opaque receiver case that is fuel proof, and which improves
durability and reliability, especially in larger 1/8-scale nitro
vehicles. The Pro Series receivers also feature improved firmware that
prevents ESD (electro-static discharge) issues from the get-go.
What about ESD???
Some racers experienced something that did not crop up in initial
product testing: an electro-static discharge (ESD) issue. Most of the
initial testing on Spektrum Modules and receivers were done on asphalt,
but once the indoor carpet season began, some ran into issues where the
fail-safe on the receiver would kick in, essentially shutting the car
down. Between several testers, it was found that a firmware upgrade to
the receiver would eliminate the ESD issues. Additionally, it was
discovered that the routing of the transmitter’s antenna wire inside
the module case placed the wire directly over the power capacitors.
There were times when this placement of the antenna lead could cause a
driver to experience glitching issues. Again, Spektrum Engineers came
up with a fix that was easy and effective. A new antenna was designed
with a longer lead on it that allowed the wire to be routed around the
side of the RF board instead of over it. All the standard and Pro
Series modules and receivers shipping now feature all of the firmware
and antenna updates. Additionally, those who already purchased Spektrum
systems before May of 2006 can simply send in their system for the
firmware and antenna updates to be made free of charge.
From the mouths of the racers
The ultimate test of any product is how it performs in the hands of
the end users, not the engineers. We’ve talked with a number of racers
recently to get their take on Spektrum latency since the introduction
of the Pro Series.
Travis Amezcua—Team Losi Factory Driver; Multi-Time National Champion and IFMAR Worlds Finalist
I started using the original Spektrum system at the Reedy Truck race
in 2004 when it was still in the prototype stages. During the past 2
years, I have used Spektrum modules and receivers and spent many hours
track-testing the system with one of our designers, Mathew Lee. From
the first day I started using Spektrum to today, I've only gone back to
a normal crystal-based radio system once. I did this as an experiment
and to simply try it out again.
When I did, boy did I have a bunch of glitching problems. Since that
last test, I will never go back to crystals again. With the release of
the super-tiny SR3500 micro receiver, it’s now the only receiver I use,
and I run it in every car that I race. From 1/8 gas off-road to 1/10
electric off-road, the new SR3500 is bulletproof, both in terms of
durability and signal quality. Since I have upgraded my radio to
Spektrum 2.4GHz DSM equipment, I've never once had any kind of a radio
problem. And for those who think that Spektrum slows you down, I have
won more than a few National Championships with Spektrum equipment in
my cars. The proof is in the results.
Todd Hodge—Team Manager, Team Losi
I was lucky enough to be one of the first testers for the Spektrum
equipment. I felt it was the greatest and most innovative idea for an
RC product that had ever been designed. As we headed into the carpet
season with our touring cars, we felt that there were some potential
problems with the latency. We changed back to our crystal-based
equipment soon after that.
Recently, however, I was introduced to the new Spektrum Pro Series
modules and the new Spektrum SR3500 Micro Receiver. While attending the
IFMAR Touring Car World Championships in Italy, I was experiencing
major glitching problems and needed a fix fast. I installed the new
Spektrum Pro Series Module in my JR Z-1 and SR3500 Micro Receiver in my
Team Losi JRX-S Type R touring car and never looked back. It was
awesome. I never experienced another problem the rest of the weekend.
Back in the States, I have continued to use the Spektrum Pro Series on
carpet and found that it works flawlessly. It has no latency issues
that I can feel. I will be running the entire season with the new
Spektrum Pro Series equipment to ensure the proven preciseness that has
been incorporated into the new Spektrum Pro Series Module and SR3500
Micro Receiver.
Jon Kerr—Team Schumacher USA Factory Driver
I first used one of the original M8 Spektrum module and receiver
units in 2005 for the Reedy Race of Champions. I've had radio issues at
the Tamiya America facility in the past, but this time I didn't have a
single glitch all week. As a serious competitor, however, I could feel
the slight latency in the system on the track and couldn't adapt my
driving style to overcome it. Several months later, I returned to using
crystals and my results improved once I did.
With these previous experiences, I was more than a little skeptical
to try the Pro Series system when it was released. After talking to a
number of other racers, I decided to give Spektrum a try again and I'm
very glad I did. Now I feel no delays whatsoever when I am on track. If
anything, my car feels more responsive than it did with crystals. I'm
able to enjoy the benefits Spektrum offers and still be confident that
I'm not going to have any radio issues. This is how radio systems
should be made.
Sonny Brown—2005 Snowbirds 1/12 Scale Oval Champion, Former ¼ Scale Champion and Race Promoter of the Brushless Racing League
As a racer, I’ve been using the Spektrum system in competition for
almost two years now and have never had an issue with my car feeling
non-responsive. With the speed of today’s modified oval cars you need
to feel connected every time you hit the track. The Spektrum system I
use in combination with my JR Z-1 radio delivers the confident
comfortable feel I’m looking for time after time.
As a race manager, the Spektrum system is one of the greatest
innovations to come along in years. It simply speeds up the race
program. Fewer frequency conflicts cause after qualifying re-sorts
cause less time delays and help keep my race programs running smooth.
David Weir—2003 Tamiya Championship Series Mini National Champion
When I first read about the Spektrum system release, I was eager to
give it a try, as it sounded almost too good to be true—no crystals and
no conflicts to worry about. All of my expectations were met by the
original Spektrum performance. No glitches, no conflicts, just walk
right up to the drivers stand and turn it on. As I race primarily on
carpet in a building with fluorescent lights, WiFi, and cordless
phones, I was pleased to find virtually no problems. The sole issue I
experienced on rare occasions was due to the ESD issue. Thankfully, the
problem was quickly solved by the timely (and free) software update.
When the Spektrum Pro Series was announced, I was skeptical about
the claims of reduced latency, but decided to give it a try. After a
year of racing with the original Spektrum system, I had noticed just a
slight latency in the system, something I only noticed "at the tone"
start of the race. While some might say you shouldn't be able to tell
the few microseconds difference, I immediately noticed that, with the
Spektrum Pro Series equipment, I had a much more immediate response on
the tone. Until I became accustomed to the faster response, I also
found myself turning in just a touch early to each corner, but after
just a couple of battery packs I adjusted to the faster response time.
As I love to race Tamiya Mini Coopers, I was also very impressed
with the new SR3500 micro receiver—a true work of art. It is so small
that I can now bury the micro receiver and my speed control down low
and within the small confines of the mini chassis for a nice low center
of gravity and neat appearance. The 2006 TCS Nationals had over 150
drivers participating, and it was a pleasure to never wait for a
frequency clip, never have a glitch, and be fully confident of radio
control of my car. I'll never go back to crystals again.
Rapid Response
As for my personal experience, I race at a variety of events from
local club races, the US Touring Car Championships (The Novak Race), to
the Tamiya Championship Series regional and national events. I started
running the original Spektrum system during the summer of 2005, first
in my Sportwerks Mayhem, then in my Tamiya TA-05. Now every car I own
has Spektrum equipment.
I have attended the Tamiya Nationals every year since 1999 in Aliso
Viejo, California at Tamiya’s headquarters. The track is known for
having radio issues, and I have had glitching issues there in the past.
The 2005 Nats was the first big race I ran a Spektrum system in and it
was pretty sweet. I never had to wait for a frequency clip in all of
practice, and I never had a single hit.
A few months later, I was able to test the Pro Series equipment in
both my brushless and stock rubber Team Losi JRX-S cars at the 2006
Novak Race. I didn’t realize why at the time, but I kept turning in
early for corners. It was the weirdest thing and I couldn’t figure it
out until after the event. I had adjusted my driving style to drive
around the latency without thinking about it, and one of the
adjustments was to turn in earlier for corners and turn up my expo.
I have since adjusted to the faster response time and love my Pro
Series equipment. I also like that I can still use my SR3000 receivers
in my cars I just play around with, so I can still get use out of my
original equipment. Oh, and at the 2006 Tamiya Nats, I also ran a Pro
Series Module with the new SR3500 Micro Receiver. Again, I practiced
when I wanted, never waited for a clip, and never had a radio hit. In
fact, I never thought about my radio or frequency once all week. It was
super dialed.
There can always be confusion, misconceptions, and otherwise bad
information in the responses heard when a new technology is introduced.
When it comes to Spektrum technology, Spektrum is a fluid sort of
product and the development never ceases. A radio system’s speed and
response time is all relative. With improved latency and a broad range
of products available, there’s no good reason not to upgrade to
Spektrum equipment. After all, the guy who just passed you probably did.