Originally Posted by
ntrain42
After doing research on this matter, frequency hopping does not necessarily take x amount of time to switch from frequency to frequency. And the examples given by you in the elapsed time domain are definetly off in that regards, especially since we are talking about 2 different forms of frequency hopping, packet size transmitted etc.
I am not a expert in this field by any means, but the reality of the matter is that upgrading to a servo with a faster transit speed will make a much bigger difference than worrying about 2.4gig tx/rx response time. Over the last few weeks Ive played with a number of these 2.4gig sport and competition radios, and in reality they all perform pretty much on equal footing in terms of absolute speed in terms of real world response. I think the most important issue is what you get for features for your dollar spent. For me personally I couldn't see myself paying 125 bucks or more for an Airtronixs M11X or 200 plus dollars more for a Futaba 4PKS over the price I paid for the DX3R Pro. For me, if the prices were reversed I would have easily picked up or opted for the M11X or 4PKS if they ended up being priced better vs. the SPektrum Pro radio.
I'm not an expert in the field either (not an RF guy by trade), but I have taken multiple classes in the field. Admittedly, the design of the systems we are using are not open, but the assumption that only a single 'packet' is transmitted before a hop (note that not all hops will actually result in a change in transmit frequency) is just as likely as not. Only a single value for each channel will be embedded in each packet and time between packets is directly related to latency. The number of packets lost to noise is just an approximation, but I've seen worse in a lab setting with artificial noise, I can imagine a noisy RF environment being similar. And, even with my approximations, if multiple packets are transmitted before a hop, noise will have an even greater impact, not less, leading to an even bigger impact on perceived latency (say 10 packets are transmitted between a hop, if there is narrowband interference, all of those packets will be lost).
That being said, I am interested in learning, and would love to see what you found that shows my assumptions to be erroneous.