FlyingGiants - View Single Post

USN_POPS · 03-10-2008, 01:13 AM

I sent an email to XPS tech support to see if there was validity in this set of test results. These negative posts about XPS is causing some problems at the field. People see what I am using and think it is unsafe after reading all the bad press in these forums. So I asked for clarification. Within 12 hours I received this response:

"We have not seen the video. We can't access the flying giants site
apparently. Obviously we know it hops and it has been demonstrated by a
few others already. We have also demonstrated this to the powers that
be (AMA, MAAA, Graupner, etc.) so we have never been concerned about
someone not being able to make it hop using bench test equipment. We
don't fly our planes sitting on a bench.

We have stated before that our system uses a predictive hopping scheme.
The only time our it hops is when the noise floor is rising/falling in
a predicted pattern, long before any type of potential problem occurs.
The idea behind this is to increase the range. Less noise = longer
range. As stated repeatedly, REAL WORLD tests clearly show that when a
single frequency on 2.4HGz is saturated, the entire band is also
saturated. It does no good to hop when there is clearly no place to hop.

However, to make the masses all warm and fuzzy, we are making a small
change to the firmware that allows the system to hop during a fail-safe
condition *if* there is actually an available frequency. So, people can
perform their bench tests and easily see the change (and feel happy).
In reality, the only time we have ever seen a case where this is needed
is when a high power 2.4GHz video transmitter is being used directly
next to the receiver (and is turned on after our system is turned on).
You can also completely lock out a Spektrum system using two video
transmitters next to their receiver. It needs to be clear that bench
test conditions do NOT replicate the reality we have at our flying
fields or in the air. We have traveled the country monitoring the
2.4GHz band, and there are simply no locations where a single frequency
is turned on randomly, and with enough power to effect our system.
Interference either occurs across the entire band and causes a problem,
or does not cause a problem at all. In every case we have seen, ISM
devices always co-exist, even on the exact same frequency. It is
required under FCC/IC/ETSI rules to co-exist. Non-ISM devices do not
have this requirement. Non-ISM devices would be video transmitters and
radar. Video transmitters can only affect our system in the direct
vicinity. Radar saturates the entire band, so it kills ALL 2.4GHz
systems, including those that use true frequency hopping.

Our system is the only system that uses bi-directional communications to
immediately re-send data that is lost. All other systems require that
they wait for the next frame. It is certainly possible to have many
frames coincide with bad data and thus you lose complete control during
this time. With our system, you don't. That's easy enough to "bench
test" as well.

We do have to say that our competition is doing a great job of stirring
up things. We appreciate the extra attention we are getting.

You are welcome to post this information to the flying giants website."

And here it is - straight from the horses mouth. Do we fly airplanes or just sit around doing bench tests. For me it's in the flying that proves the system.

03-10-2008, 01:13 AM	#40
USN_POPS Seasoned Veteran Join Date: Jul 2007 Location: Enumclaw, Washington Posts: 296	Re: Kiwi's XPS test results are up. I sent an email to XPS tech support to see if there was validity in this set of test results. These negative posts about XPS is causing some problems at the field. People see what I am using and think it is unsafe after reading all the bad press in these forums. So I asked for clarification. Within 12 hours I received this response: "We have not seen the video. We can't access the flying giants site apparently. Obviously we know it hops and it has been demonstrated by a few others already. We have also demonstrated this to the powers that be (AMA, MAAA, Graupner, etc.) so we have never been concerned about someone not being able to make it hop using bench test equipment. We don't fly our planes sitting on a bench. We have stated before that our system uses a predictive hopping scheme. The only time our it hops is when the noise floor is rising/falling in a predicted pattern, long before any type of potential problem occurs. The idea behind this is to increase the range. Less noise = longer range. As stated repeatedly, REAL WORLD tests clearly show that when a single frequency on 2.4HGz is saturated, the entire band is also saturated. It does no good to hop when there is clearly no place to hop. However, to make the masses all warm and fuzzy, we are making a small change to the firmware that allows the system to hop during a fail-safe condition if there is actually an available frequency. So, people can perform their bench tests and easily see the change (and feel happy). In reality, the only time we have ever seen a case where this is needed is when a high power 2.4GHz video transmitter is being used directly next to the receiver (and is turned on after our system is turned on). You can also completely lock out a Spektrum system using two video transmitters next to their receiver. It needs to be clear that bench test conditions do NOT replicate the reality we have at our flying fields or in the air. We have traveled the country monitoring the 2.4GHz band, and there are simply no locations where a single frequency is turned on randomly, and with enough power to effect our system. Interference either occurs across the entire band and causes a problem, or does not cause a problem at all. In every case we have seen, ISM devices always co-exist, even on the exact same frequency. It is required under FCC/IC/ETSI rules to co-exist. Non-ISM devices do not have this requirement. Non-ISM devices would be video transmitters and radar. Video transmitters can only affect our system in the direct vicinity. Radar saturates the entire band, so it kills ALL 2.4GHz systems, including those that use true frequency hopping. Our system is the only system that uses bi-directional communications to immediately re-send data that is lost. All other systems require that they wait for the next frame. It is certainly possible to have many frames coincide with bad data and thus you lose complete control during this time. With our system, you don't. That's easy enough to "bench test" as well. We do have to say that our competition is doing a great job of stirring up things. We appreciate the extra attention we are getting. You are welcome to post this information to the flying giants website." And here it is - straight from the horses mouth. Do we fly airplanes or just sit around doing bench tests. For me it's in the flying that proves the system.