spread spectrum 900 mhz

[forgues research]

Its coming guys, the best spread spectrum of all 900 mhz better conrolled

Roger

[ferocious frankie]

Details?

[forgues research]

	Quote: Originally Posted by ferocious frankie
	Details?

The only details I can tell you at this point is 2.4 can be dangerous since it is called the trash frequency and the only reason the manufacturers went this route is because all chip sets are readily availlable very cheaply.

The 900 here in question will operate differently and be the safest also more distance ...

Roger

[rking]

in asia, cellular phones run on the 900 and 1800mhz band

[Mithrandir]

XPS has/had a 900 mhz I heard from the rumour mill

[Kiwi]

It certainly wont get into a whole bunch of countries as 900 Mhz is locked up tigher than a fishes butt (thats water tight) for cell phone use. You cant even buy a scanner on 900Mhz as its against the privacy regulations.

I suppose it will be legal in the USA but not a lot of other places unfortunately.

[XJet]

Yes, the 900MHz ISM band is pretty much a US thing. In many other countries only a very small subset of the band (or none at all) are available for non-licensed applications.

I agree with the fact that the 2.4GHz band was chosen as an alternative by RC makers simply "because it's there" and because the chipsets are so ubiquitous and cheap.

I still fly my most valuable models on 72MHz PCM (wink, wink). The chances of interference on that frequency (here in NZ) are far lower than the chances of getting hit by noise on 2.4GHz -- although both are very remote.

[forgues research]

	Quote: Originally Posted by XJet
	Yes, the 900MHz ISM band is pretty much a US thing. In many other countries only a very small subset of the band (or none at all) are available for non-licensed applications. I agree with the fact that the 2.4GHz band was chosen as an alternative by RC makers simply "because it's there" and because the chipsets are so ubiquitous and cheap. I still fly my most valuable models on 72MHz PCM (wink, wink). The chances of interference on that frequency (here in NZ) are far lower than the chances of getting hit by noise on 2.4GHz -- although both are very remote.

72 is still one of the best frequencies for model airplanes,

Roger

[HuckinChikn]

hmmmm.....

[rking]

	Quote: Originally Posted by forgues research
	72 is still one of the best frequencies for model airplanes, Roger

that isn't always the case. here in the philippines, specially within the city limits, 72mhz is notorious for getting hit. radio transmissions are all over the place and so far, 2.4 spektrum systems have been the most bullet proof.

i've also noticed 72mhz (particularly on my old airtronics rd8000) to glitch a lot when i fly close by to huge power transmission towers.

======================

europe is also on the GSM band on celphones so that should eat up the 900mhz band as well. i just wonder how XPS would be able to get around the millions of cellular transmissions in our parts of the world.

[ferocious frankie]

Wow, now I'm looking forward to this.

[XJet]

900MHz is not a universal panacea either.

It is an ISM band (so the same "free for all" license system applies) and whereas the 2.4GHz band is around 80MHz wide, the 900MHz one is around one third that big. This means that, if the amount of use is the same, there will be more contention for spectrum within the 900Mhz band than the 2.4GHz one.

There's also a greater risk from cellphones and pagers, even Digi (formerly MaxStream) acknowledge this. What's more, due to lower path-losses, a 900MHz signal tends to travel quite a bit further than a 2.4GHz one (for a given power/antenna configuration) which means that more potential interference sources will be visible on 900MHz than on 2.4Ghz once a model leaves the ground.

Unfortunately, since I don't live in the USA and we here in NZL don't have any ISM rights to the 900MHz band, I have no idea if there's enough noise in that part of the spectrum to be an issue for RC models in the countries where it's legal - but I suspect not.

It will indeed be interesting -- but really only an option available to those in North America, Israel and Australia.