Just got a new (used) Futaba 8UAF? transmitter on e-bay. In reading there seems to be 2 methods of operation, PCM, and FM. I currently use an FM Tx, Rx, and standard servos. Will I need to get a new Rx? Servos??? What is the advantage if any with PCM? Will I just need to get a new freq crystal to operate my current plane? I would 'preciate any info.
Thanks in advance,
Rich
World Class Navigator, low time pilot.....
On 26 Jun 2005 18:54:37 -0700, "rich" wrote in :
If it is Futaba-compatible, no. Just select FM for the RX, hook up some batteries and servos, and test it. It should work.
No need to upgrade.
PCM lets you create default settings for each channel. If the signal gets lost, you can have the engine slow down or cut off completely, put in some aileron deflection, and perhaps a little up elevator. If you're lucky when the TX goes out, your plane might land itself. Or you might regain control before it hits the ground.
PCM might be a little more selective than PCM. I don't honestly know. I've heard stories (unverified) that a PCM TX and a standard FM transmitter on the same channel didn't interfere with each other. I wouldn't count on it, but maybe it could help save a plane if someone inadvertently turned on a non-PCM TX on your frequency.
If your RX is already on the same channel, no.
If it is not on the same channel, yes.
Marty
Rich- You may not need a new Rx, if it is Futaba or another brand that uses negative modulation shift, i.e., Hitec. If your Rx is Hitec, just get a crystal (Hitec only) to match the Tx channel. If the Rx is Futaba and IF it is in the same (upper or lower) half of the 72 Mhz band, you can do likewise. For example, if the Tx is in the lower half, below ch 36, and the Rx is also, then just get a matching Futaba Rx crystal. If not, send the Rx to Tony Stilman at Radio South to change the crystal to the Tx frequency and retune the Rx. The main advantage of PCM is that it provides you with settable fail-safe modes that few among us actually use, and it provides the distributor with greater profit. If your current Rx has positive modulation shift (as JR and Airtronics), then it won't be compatible with your new Tx. Buy a new Hitec Rx for good performance and value. The servos are generally compatible electrically, though not always as to connectors. If the connectors fit, use them. If not, come back here and somebody will show you how to adapt them.
Abel
The 8U is a good TX. Reportedly (maybe just "urban legend"... not sure
it is susceptible to interference if a cell phone is within a couple o feet of it. (so to fail on the safe side... leave any cell phone in th car when youare flying... you shouldn't answer the phone while flyin anyway)
The full manual for it is available as a PDF from Futaba's website. I would be a good idea to download and print it.
8UAP defaults to PCM fixed wing mode.. 8UAF defaults to PPM fixe wing... 8UHP defaults to heli PCM.. 8UHF defaults to Heli PPM. There' little to no programming difference, but some of the switch labels ar different for the heli versions than the fixed wing versions. (They al use the same insturction manual)DO NOT use the 9C_Z Synth module in one.. there is a synthesize frequency module that will work in it though. (its cheaper than gettin
3 specific frequency modules to get one synth module-- fhhuber50677
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Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:
All the information provided is very good.
HOWEVER, they forgot to mention one thing. If you are going to use regular FM, your present receiver is just fine. If it is on the same channel you are OK, if not, get a receiver crystal for your channel. Don't worry about the high/low thing unless you are going from one end of the channel spectrum to the other - from channel 4 to channel 58 for example. If you are doing that, I would send the receiver back to Futaba and have them do "their thing" just to be safe.
The one thing they forgot is: IF you decide to go with PCM, you will need a new receiver. The PCM receivers are a little different (and a lot more expensive) than a regular FM receiver.
If you go the PCM route, make sure the receiver is going to work with your transmitter. At present there are no set standards for PCM. Everyone has their own method of doing it AND the method changes periodically within the brand. A Futaba PCM receiver for a transmitter of a different model (or several years old ), in all probability, is not going to work with your transmitter.
Thank you all for the great information!!! One last question: Can you change the freq on the Tx, by just plugging in a crystal? That would seem easier than changing crystals on 4 different planes. If not, then I guess it's another trip to the LHS!
Or I could be really, really lucky, and the Tx will already be on channel #38!!!
Sure.....
Regards,
Rich.....
If you're in the US you are not supposed to change the Tx frequency, unless you are authorized and have the equipment to confirm it's still transmitting within spec. Sending it to a service place and having them do this would probably be about the same as the cost of those 4 Rx crystals. This is also thing to do since this Tx is not new and you can't be sure of it's history. The safe thing to do is have it checked before you use it. Better this than losing a plane.
Tower Hobbies prices:
9C/8U Single Freq Tuner Block (72Mhz) (LXH256**) = 49.99 9C/8U Synth Freq Tuner Block (72Mhz) (LXHKB1) = 89.99 (now listed as available late July)I was lucky enough to get one from the first batch Tower Hobbies had. Looks like they are out again.
d.tipton
The current Futaba PCM receivers will work just fine with your 8U transmitter. Be sure the receiver is PCM 1024...that's it.
The 8U uses RF modules (there is a crystal in the module) that you swap out to change channels. Since the module contains all of the 'tuning stuff' you can swap them legally. You just have to get modules on each channel you need. Bad part; modules are about $50 each.
| Tower Hobbies prices: | 9C/8U Single Freq Tuner Block (72Mhz) (LXH256**) = 49.99 | 9C/8U Synth Freq Tuner Block (72Mhz) (LXHKB1) = 89.99 (now listed as | available late July) | | I was lucky enough to get one from the first batch Tower Hobbies had. Looks | like they are out again.
If you're after the synthesized frequency module, I saw two (I think) at Discount Hobbies in Georgetown, TX on saturday. The price given was the same as Tower -- $90 -- which is why it stuck in my head (I like Discount Hobbies -- they don't jack up the prices like the other hobby shops around here. The downside is that it's 30 miles away ...)
You could order it from them. Their web site is
-- The Spectra module has the switches on the back. You have to remove the module to change or even see what channel you're on. This encourages just going from memory, which could very well be wrong. (I'm glad to see that Futaba moved them to the front, where you can see it even if installed.)
-- Both modules use those damn small little knobs. It's so easy to put them on the wrong channel, or to get channel 34 confused with 43.
Really, what they need to do is make bigger knobs for adjusting the channel, and put a set of big red LEDs (or some LCD digits) on the back that display the current channel. Perhaps get rid of the knobs entirely, and just have four buttons -- up 1, down 1, up 10, down 10, and the LED display. Whenever you push a button, the RF power stops until there has been no button pushing for 10 seconds. And perhaps another button to `arm' it -- we don't want somebody to bump the buttons in flight, after all.
Some simple (and relatively cheap) modifications to these modules could easily do away with most of the `dial a crash' issues. Adding a small receiver where it would refuse to turn on on a channel that's in use would be nice too, but that wouldn't be _quite_ so cheap.
Anyone know how much of an energy hog the futaba synthesized frequency module is (the one for the 9c)? I knew a guy with the Hitec spectra module and it cut his battery time in half. I also know a guy with the futaba 10z and a synthesized module and he gets a little over an hour with his set up. Right now I get about 6 hours with my 9c and a 1650 mah nimh battery. After
6 hours I am a little over 9 volts.
babycakes!
The "new" synth block for the 9C shouldn't draw any more than the fixed frequency block since the "new" synth block was designed for the 9C/8U. Spectra modules were designed for the HITEC circuits so the battery drain would of course be different.
I need to do a load test on mine. Haven't had a chance to use my 9C synth block yet.
d.tipton
Where does everybody get the notion that the 9C Synthesized module is
functional AND BLESSSED to work with an 8U? I see nothing in th Tower writeup. Or is this another idea like the Spectra module in th
8U, which also is NOT BLESSED. In fact the AMA sez you don't have an liability protection if you use a Spectra in an 8U (it was very late i coming about for sure). Now, do they have to make a similar statemen about this 9C module or is there some legal writeup somewhere to thwar this?? (Futaba doesn't like the foreign RF modules either in the 8U) FCC don't like it either(stated now on the Hitec Spectra modul webpage).I'm looking for the ultimate 'expert source' on the matter... who ca definitively state what will/will not legally work with what. suppose radio equipment will be checked at the contests this summer t insure AMA compliability and assure there is no possibility fo bringing down someone else's plane or worse..
BTW - I'd like to own an 8U with a Synth module , if I can find a lega one
-- daSelle
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| Where does everybody get the notion that the 9C Synthesized module is | functional AND BLESSSED to work with an 8U?
Well, all the other TP modules made for the 9C work in the 8U (and 7U) and vice versa, so people probably assume that this one is no different. That, and Futaba has been promising a 9C/8U synthesized module for a long time.
But you're right -- the description does say 9C, but not 8U.
| Or is this another idea like the Spectra module in the 8U, which | also is NOT BLESSED.
I think the term you're looking for is FCC certified.
| In fact the AMA sez you don't have any liability protection if you | use a Spectra in an 8U
No, the AMA has said that it may endanger your liability protection. Not that you have no protection. The two statements are similar, but different.
| Now, do they have to make a similar statement about this 9C module | or is there some legal writeup somewhere to thwart this?? (Futaba | doesn't like the foreign RF modules either in the 8U)
If you read
Based upon FCC regulation 95.645(b), and the advice of our lawyers and the AMA who have analyzed and discussed this issue with the FCC, we must indicate that we believe that any non-Futaba module to be against FCC regulation to use in a Futaba transmitter.
Now, this was written before the TP-FSM module came out, so maybe they just haven't updated it. Also, the 8U has been discontinued, so maybe Futaba just didn't bother to explicitly certify the new module with it.
| FCC don't like it either(stated now on the Hitec Spectra module | webpage).
Lots of people guess at what the FCC has to say about matters. Far fewer actually read the regulations properly, and fewer still actually ask the FCC. In this case, I believe this statement to be correct, but just because you find a web site that says something, that doesn't make it true.
| I'm looking for the ultimate 'expert source' on the matter...
Then you're in the wrong place. You'll want to contact either the FCC or Futaba. The best you're likely to find here are educated guesses.
| who can definitively state what will/will not legally work with | what. I suppose radio equipment will be checked at the contests | this summer to insure AMA compliability
It's the FCC you have to worry about. The AMA just follows their lead.
As for equipment being checked at contests, the degree of checking is hardly uniform, and contests make up only a small part of the flying that goes on. And I imagine that very few contest directors will actually know to not permit a TP-FSM module in an 8U radio -- if they check at all, they're likely to just see Futaba on the module, Futaba on the TX and say OK.
| and assure there is no possibility for bringing down someone else's | plane or worse..
I think it's pretty well established that the Spectra module works properly in the 8U and 9C, and I would assume that the TP-FSM works correctly in both as well (but I have not tried it) so the issue is not that it will `bring somebody else's plane down' but that the FCC (and therefore the AMA) may not like it.
| BTW - I'd like to own an 8U with a Synth module , if I can find a | legal one!
Then contact Futaba. Or the FCC -- they do keep track of certifications, and can probably tell you authoritatively if the TP-FSM has been certified on the 8U radios or not.
There has been a synth module that WAS rated to work in the 8U... chec
the FutabaRC website. (I looked it up there, not at Tower.. about months ago. It was a TP series module but NOT the current FSS.
-- fhhuber50677
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Go to
Thanks for the 'perception', really! I believe this is all that it is
and from everyone that I talk to. I need to see this in officia writing; what is the reason it is not? People also replace crystals i their USA Tx and say it works, and that too isn't permitted. In al cases, no one seems to have the ability to technically scope this ou and prove it one way or the other. Other Equipment Manufacturers Compatibility claims are the mos 'expense in time' to make by any company for the payback, so it doesn' surprise me that the FCC, AMA, Futaba, or Hitec are not willing to g out of their way to make them. Until then, it is unofficial! Practically, if it isn't tested or designed as such, it isn't going t work. And none of us experts can rely on our own observations to mak such claims. Any lawyers listening? This is a hobby; there are safety and property concerns if you not flying completely alone out in the middle of some tundra
-- daSelle
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