whats so good about 2.4 ghz?!?!?!?
#76
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RE: whats so good about 2.4 ghz?!?!?!?
Haven't read the whole thread, but I still run the 40mhz stock radio from my LST2 - with all four of my RC's.. Now with everybody else running 2.4, I really never have a problem.. Range, disturbance, etc.. - nothing to complain about.. Except maybe broken antenna tubes.. Only down-side really.. Plus I'm not going to spend the price of a whole new car for a new radio with four receivers to replace what I have now that works perfectly fine...
#77
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RE: whats so good about 2.4 ghz?!?!?!?
ORIGINAL: ThunderbirdJunkie
It's so cute that downunderdog remembers all of ThunderbirdJunkie's posts from other threads nearly verbatim. Or has the time to kill to go back and look at them, whichever.
It's so cute that downunderdog remembers all of ThunderbirdJunkie's posts from other threads nearly verbatim. Or has the time to kill to go back and look at them, whichever.
do his research, as in actual usage higher frequencies tend to suffer effects of distance more than lower frequencies. Downunderdog thinks it's due to the shorter wavelength in higher frequency transmissions - more attenuation by atmospheric factors or things that get between source and receiver. Just have a look at the FPV pilots - for a given transmitter power output and antenna gains, 900mhz will have better range than 2.4ghz or 5.8 ghz video links. Downunderdog's research has indicated that lower frequencies both penetrate obstacles better (that's why they use ULF for communication with submarines) and is attenuated less due to atmospheric factors (i.e. humidity, etc.). So, for ultimate range of RC transmitters and receivers, Downunderdog believes that the lower frequency spectrums (i.e. 27 Mhz AM, 72 Mhz) are THEORETICALLY better. However, as it's rare that Downunderdog would be operating a RC vehicle on the moon, ultimate theoretical range is neither here nor there... but I'm surprised that ThunderbirdJunkie and ThunderbirdJunkie's Mini-me did not bring it up.
ThunderbirdJunkie has brought up a lot of irrelevant things in defense of 72/75 MHz, such as:
- RC jets using 2.4 gig and crashing (then ThunderbirdJunkie backs away from this statement and says that any frequency can be interfered with)
- RC jets using 2.4 gig and crashing (then ThunderbirdJunkie backs away from this statement and says that any frequency can be interfered with)
- Reliability (ThunderbirdJunkie has yet to clarify how 2.4ghz is less reliable than FM)
Your normal PCM/otherwise one-frequency-bound radio, however, has been proven over the decades. DSS/FHSS has not yet been shown to be so as of yet, and with the lower and lower quality goods being pumped out because people want everything for next-to-free, it'll be shocking if we ever see the true potential in longevity.
- Ease of service (ThunderbirdJunkie has yet to clarify what this means)
- Latency (first ThunderbirdJunkie brings up the fact that RC Jet flyers use 2.4 Gig, then ThunderbirdJunkie says that 2.4 Gig suffers from ''Latency'' issues. Curiously, ThunderbirdJunkie did not supply a link or any supporting information, as is usually the case.)
- ''bind-and-drive ability for a theif…'' (actually with all of the different spread spectrum 2.4 gig formats out there, Downunderdog believes that it would actually be easier to steal a 72 or 75 Mhz equipped vehicle - the RX's are interchangeable between brands, aren't they? Just change a crystal and off the theif goes. With 2.4 gig, most TX/RX combinations are brand specific.)
ThunderbirdJunkie is lucky that ThunderbirdJunkie's Mini-me's research did not lead him to throw in the old ''signal attenuation affects range'' argument in there. Downunderdog actually believes that the fact that AM DOES travel a long way is one of it's major weaknesses. A transmitter on the same frequency that is VERY far away (maybe even on the moon, if one cares to pursue hyperbole like ThunderbirdJunkie has been known to) can cause interference with an AM user right here in a park on earth. The real truth is that the all of the available frequency spectrums that have been allocated for RC model use have enough theoretical range to go beyond what any of us would normally need (except maybe FPV pilots who fly beyond visual range). What sets 2.4 gig apart is the extra bandwidth that is available at the higher frequency. That bandwidth can (and is) used to differentiate the signal from the noise. The TX can send a lot more data to the RX, and the RX can process the data to determine what is being transmitted by what it is bound to and what is noise or interference from other, unwanted, sources. So, while 27 Mhz or 75 Mhz may have more theoretical range, 2.4 gig actually has more USEFUL range because it filter out the interference, and the model does NOT do what 5 (or even just 2) different things that are all within range are telling it to do. It just does what the one transmitter that it is bound to tells it to do.
#79
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RE: whats so good about 2.4 ghz?!?!?!?
ORIGINAL: ThunderbirdJunkie
If you don't believe it, that's fine. Do your own research and prove ThunderbirdJunkie wrong if you really wish to debunk his every statement. It's something that can be felt in two similarly equipped cars.
- Latency (first ThunderbirdJunkie brings up the fact that RC Jet flyers use 2.4 Gig, then ThunderbirdJunkie says that 2.4 Gig suffers from ''Latency'' issues. Curiously, ThunderbirdJunkie did not supply a link or any supporting information, as is usually the case.)
From Spektrum's website, some information [link=http://www.spektrumrc.com/DSM/Technology/DSM2.aspx]about Latency.[/link]
"With DSM2, the total latency of your radio system has been greatly reduced, while the bit-rate has been increased. When combined, these improvements provide hobbyists with a faster and more locked-in feeling when compared to traditional 27MHz, 72MHz, or 75MHz radio systems."
Does ThunderbirdJunkie have a link to anything that discusses latency comparisons between 72/75 MHz and 2.4 GHz systems which indicates 2.4G is worse? Or does ThunderbirdJunkie prefer to speak in generalities like "Latency. It's something that can be felt in similarly equipped cars." ThunderbirdJunkie never even stated whether the latency of 2.4 G was greater than or less than 75 MHz, or how the effect made the cars feel. Perhaps ThunderbirdJunkie believes that higher latency of 75 MHz makes the feel of the cars better? Could ThunderbirdJunkie please clarify?