User's Manual
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RadioPopper PX Radio Wireless System
Identifying Radio Interference
When a clean link is established between a PX Transmitter and a PX Receiver, the PX Receiver will turn on the orange Link
LED. Any time this signal is lost, interrupted, or other unexpected signals cause a conict with the signal the receiver is
expecting to see - the Link LED will go out. The Link LED will turn back on as soon as the PX Receiver is able to make out
the correct signal through the “noise” of the interfering signal.
In the presence of interference you may observe the Link LED on the PX Receiver is not solid - it may be ickering or
strobing, even when in close range of the PX Transmitter. In this condition, you may have intermittent interruption in
the operation of your PX system.
You may also observe erratic operation of your slave ash. Any conicting background signal is reproduced as short
blinks of the light source inside your PX Receiver, which are seen by the sensor of your slave ash. In most cases, these
erratic blinks don’t match any timing your slave ash is programmed to respond to so they are disregarded. In some
cases, the random timing of these blinks may exactly match an instruction your slave is programmed to. In this case it
may emit short pops of light or perform other erratic behavior.
Once you have identied an issue of interference, repositioning the slave ashes may correct the problem. In many
cases, your PX system will still operate in the presense of interference to a satisfactory level as to allow continued use
without changing location. In other cases moving just a few feet may be enough to get away from the interference.
Sources of Intentional Radio Signals
Some electronics intentionally emit radio signals. Your PX Transmitter uses the United States certied “Industrial,
Scientic, and Medical” or “ISM” band as that is the only band the FCC will allow the type of broadcast required to make
this system possible. This band is quite wide with lots of frequencies available so other devices with the exact frequency
as your PX should be rare, but you may occasionally shoot at locations with conicting radio signals.
Common sources are monitoring and environmental control equipment - such as security systems and air conditioning
and heating control systems. These systems may emit a strong signal and may conict with your PX system as far as 200
ft. away from the emitting source. Some locations may have many such transmitters throughout the property which
may prevent reliable operation anywhere at the venue. The good news is these more powerful sources of interference
are very rare and not likely to reduce the usefulness of your PX system at multiple locations.
Sources of Unintentional Radio Signals
All electrical devices emit radio signals. These signals are usually very low power and won’t interfere with other
electronics. As electric devices age and begin to fail, they often begin emitting various interference. Your PX Receiver
is tuned to be exceptionally sensitive to changes in radio frequency which allow it to repeat the signal between your
ashes at such an incredibly fast speed. This does also make them sensitive to certain background radio interference.
Sources of unintentional radio signals are fairly common. The most common source of signals likely to eect your PX
Receiver are failing uorescent lights (lights operating normally pose no concern of interference), and failing computer
and TV monitors. Though this type of interference is fairly common, these signals usually have very short range, and
moving your shooting location just a few feet may be enough to get you away from the interference.
Trouble Shooting
About This Section
We have put much consideration into the design and operation of the PX system. We are condent you will experience
simple and worry free operation. Please refer to this section if you do experience any trouble while operating your PX’s.
This section is split into three segments focused on the types of mis-re or malfunction issues you are likely to encounter.
How ETTL and iTTL Work
As the RadioPopper system is simply a “relay” for an existing signal being sent between your Master and Slave ashes, it
is important to understand how the existing system works. Some of the misre events or malfunctions you may experi-
ence are directly attributable to the underlying ETTL / iTTL system built into the ashes themselves, rather than the PX
radio system.
Your ETTL / iTTL system works by causing the wireless Slave ash to emit two separate bursts of light. The rst burst,
called a “pre-ash”, is a dim ash of a known amount of light. Before your camera’s shutter opens, your camera’s meter-
ing system measures this rst “pre-ash” and based upon it, calculates the correct amount of light needed to properly
expose your image. Your camera then opens the shutter and commands the wireless Slave ash to emit the second
burst, the “Main Flash” that actually exposes your image.
Pre-Flash with no Main-Flash
One of the most common mis-re events you are likely to observe is the wireless Slave ash emitting a short “pre-ash”,
but you see no ash contributing to your actual exposure when looking at the picture in your camera’s display. It may
appear your ash is “ring”, but you don’t see any ash in your exposed image. This type of mis-re may be caused by a
combination of several factors and will likely occur in a certain percentage of exposures.
NOTE: If you are using high speed sync, please refer ahead to the High Speed Sync note on Page 29.
NOTE: This type of mis-re will only happen if you are actually using the ETTL or iTTL function of your camera (the
“automatic ash” mode). Some camera bodies, Master Flash devices or IR Controller devices allow you to remotely
adjust the power of your wireless slave ashes manually. In this case they re at the prescribed power level with each
shot without performing a “pre-ash”. You may nd greatest system reliability especially at longer ranges when setting
your ashes to this manual mode. Please refer to your camera and ash owner’s manuals as dierent hardware may
vary regarding features for remotely setting the power level of slave ashes.
1. If you’re getting a lot of these misres (anything over 10% of your images), you should adjust the Sync Interval setting
on the transmitter (Page 20). A bit of trial and error here should dramatically improve reliability.
2. In much testing of ETTL and iTTL systems without the PX System installed, we’ve found a certain misre rate when the
Master ash is red directly into the Slave ash at a range of a few feet. It is clear that even in the most ideal situations,
a certain number of mis-res will occur purely attributable to inconsistencies in the Master and Slave ash system itself.