udi maman

My Feedback: (18)

is ther a difrennce in the technilogy betwen FUTABA and JR(9303 with r921 reciver) and what is beter and more safe for jets (or ane r/c air plane)at 2.4GHZ?

GalenB

My Feedback: (18)

<groan!>[:@] This is going to be interesting...

I would suggest you start by searching this forum on RCU -- there is a lot of information and opinion available. This topic has been debated and argued very vigorously already.

aeajr

My Feedback: (2)

They are differnt and not compatible with each other.

I believe both would be fine for Jets.

I use Spektrum for small electrics and gliders as I like their remote receiver approach. You can have two receivers in the airplane so nothing can block the signal. You place them somewhat apart. I am not aware that Futaba does this.

JCINTEXAS

Udi,
Yes the "spread spectrum" methodology utilized by Futaba is different from that used by JR/Spektrum. Your question about which is better is a "Chevy vs. Ford" type of question. The answer depends on who you ask. Both brands are excellent radios. I am a FASST flier and I am very happy with my two Futaba radios.
Regards
JC

pilotpete2

A big factor to consider in your case is the power output allowed with DHSS (Spektrum), in many countries Spektrum is over the power limit allowed and must be run at lower power output, resulting in reduced range. True frequency hopping systems (FHSS) such as Futaba and the soon to be released Airtronics/Sanwa systems, they are not affected by these limits. Best bet is to check with radio gurus in your country as to the details.
Good luck,
Pete

fizzwater2

My Feedback: (61)

Since when? There's still a max output power acceptable in the band for any of these radios.

shakes268

Correct but currently spektrum has a max output higher than legally allowed by most European countries.

DougV

I have both systems, Futaba FASST for 8 months and Spektrum DX7 for a year.

Me, I like the Futaba FASST better. [sm=thumbs_up.gif]

Regards,
Doug.

udi maman

My Feedback: (18)

hi
thank you for your ansewer
i mean betwin jr 9303 2.4 with the new R921
and the futaba 2.4 ghz system

DougV

Hi:

I like JR/Spektrum programing, but when it comes to the RF Link, I like FHSS (Futaba FASST) better than DHSS (JR/Spektrum).

Regards.

aeajr

My Feedback: (2)

I believe France is the only one in Europe where the power output is a problem. I think it may be a problem in Japan too.

yakman

Futaba doesnt have anything that can compare with the 9303. They have a 7ch and a 12ch.

The 7ch doesnt have 2048 resolution, has only 10 model memories, less mixing, but it does have a snap roll button I believe. Also a ID problem which is the subject of threads around here and every other site.

The 12ch has features far beyond the 9303 as you would expect, but has a dodgey looking and apparently fragile antenna that hangs off the module. IMO it looks like a frankenstein third arm. I have also read somewhere on RCU that the speed is not as fast as the native FM, so it would seem that the JR has faster response.

p51flier

The new Euro-standard EN 300 328 Vers.1.7.1 will be valid at July 1 2008 in europe. DSSS (XPS, Spektrum,...) will then be limited to 20mW EIRP. FHSS will still be legal with 100mW EIRP. In France and Austria the frequency range for FHSS is limited from 2.400 to 2.454 GHz.

Just my 2 cents....

Mac_Man_UK

Sorry.... where do you get the 20mW from ??

EN300-328 v 1.7.1 Page 11.... (for the Non FHSS systems)

4.3.1.2 Limit
The equivalent isotropic radiated power (e.i.r.p.) shall be equal to or less than -10 dBW (100 mW). This limit shall
apply for any combination of power level and intended antenna assembly.

4.3.2.2 Limit
For wide band modulations other then FHSS (e.g. DSSS, OFDM, etc.), the maximum e.i.r.p. spectral density is limited
to 10 mW per MHz.

There are some different degrees of interpretation of the definitions as it is not 100% tied down. Regarding measurements, Section 5.7 (page 19) stipulates EXACTLY how the measurements are to be made and how to come up with the final figures.

On reflection, I believe you are mistaking the 20mW EIRP for possibly the PSD limit ? ( And as Spektrum uses 2 channels, you have assumed that 2 channels at 10mW/MHz would give 20mW).

Information available from various sources show that the Spektrum system does not transmit on 2 "channels" simultaneously but alternates between the 2 selected "channels".

Anyway, anything that is currently legal under 328 v 1.6 would still legally be allowed to be used.

Hirobofly

Hi there.
Here is a picture of the JR 9303 2,4Ghz version.... http://www.espritmodel.com/index.asp...OD&ProdID=6973
Talking about fragile solution with that thin wire and the RF-connections. Well.... I do not think the Futaba solution is so dodgey.

RJ

p51flier

Max_Man_UK,

oops, sorry, you are definitely right with the 10mW. See the attached pic which you obviously already know.

This problem will be discussed even by officials of the european community (ETSI, ECC, TCAM.....). A friend got this information from an official of the austrian ministry for traffic, innovation and technology, Dept. telekom-post. This particular answer of the ministry is posted with the permission of the ministry at an austrian rc-forum.

Joe

aeajr

My Feedback: (2)

RJ,

Sorry, but that is not the JR 9303 2.4 GHz transmitter.

That is a 72 MHz JR 9303 with an adapter module that converts it to 2.4 GHz.

udi maman

My Feedback: (18)

guys
i asked if ther is a diference betwen futaba and jr(x9303 r921) at 2.4 ghz and what is the safe one for jets?

shakes268

Which futaba? Which JR?

Spektrum DX 7
JR X9303
JR XP9303 with spektrum module
JR 10X with spektrum module
JR 12X

Futaba 7C
Futaba 6
Futaba 12FG FASST
Futaba 12Z
Futaba 14MZ


The radio features should be compared without 2.4 in mind I think. Sure the RF links differ but most of the radio features are the same between the 72 and 2.4 counterparts.
Futaba jumps channels. JR grabs 2 channels and holds on to them. Futaba has a lower voltage cutoff at the receiver level. JR has a quick connect feature to handle brownouts.

Both should pretty much be the same in jets. There was a HUGE post in the jet forum talking about the Futaba FASST system in jets.

aeajr

My Feedback: (2)

The answer is both are safe for jets. What part of that does not answer your question?

Futaba frequency hops and Spektrum/JR locks on to two channels and takes the the best signal from the two and uses it. You can get arguements either way as to which is best. Both work.

Spektrum/JR probably have a much larger installed base based on being in the market much longer but that does not make one better for jets than the other.

You have not named a specific Futaba radio so we can't compare one radio to the other but the 9303 should have all the features anyone should need or expect from a 9 channel radio. Now, if you need a 12 channel radio, that is different.

If you have specific questions you need to ask them and not make us try to figure out what you want to know.

If you want someone to say that one is bad for jets, sorry, but that would be wrong.

What else are you looking for?

udi maman

My Feedback: (18)

thank guys for your answer
i asking about the JR X9303 2.4 with R921or the FUTABA 12FGA 2.4
i realy need those 12 chanal and the diffrence in the money is not the isue
just the safe radio tx and rx

GBR2

My Feedback: (1)

If you really need 12 channels, why are you even considering the 9 channel x9303?? Your real question seems to be which 2.4GHz scheme is better. They both have their strengths and weaknesses. You really need to do a lot more reading to make your own judgement which you think is better. Opinions on the subject abound in lots of forums. Read them and make your own decision.

udi maman

My Feedback: (18)

thank for your answer
i need a 9 chanal at all my jet
so yes i asked what is beter the futaba or the jr 2.4ghz

pilotpete2

Just my 2 cents, but if you need all 9 channels in a jet, the last thing you'd want to even think about is buying a 9 channel radio, it would be a short term investment at best
The Futaba 12FG is available now on 2.4Ghz and has the benefit of not being locked into todays 2.4 technology as it's modular in design.
Pete

udi maman

My Feedback: (18)

pete
yes you rite but i can put littel macbox if i need more then 9n chanel
about futaba look her
http://www.rcuniverse.com/forum/m_6857282/tm.htm
at the new jr r921 rx ther is no glich problem any more with the new x9303 2.4