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Buying new computer tx

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Old 02-18-2005, 11:23 PM
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fastplane
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Default Buying new computer tx

As a 1 year rc pilot I am ready to buy a computer radio. What is the difference between FM and PCM?
Is the Optic a better buy than the Eclipse? -- Concerning growth of planes and complexity of adjustments?
What brand recievers and servos will they work with or not work with? I currently use JR recievers and a mix of JR and Hitec servos.
I think I want one with the spectra module. I would like to be able to use one tx for planes with different frequencies.
So what do you suggest? Thanks,
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Old 02-19-2005, 07:18 PM
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Default RE: Buying new computer tx

first of all I do not own either radio . but I can answer a few of your questions.

The Difference between fm and pcm is the modulation. Fm is a pulse position modulation and pcm is a pulse code modulation. you have a lot less chance of picking up interference. The PCM receiver are brand specific for example the futaba pcm is used with futaba radios, hitech with hitech and so on. Fm receiver you may use on different brands of radio equipment as long as they operate on the same shift and of course same frequency and channel ex 72 mhz 75 mhz. Hitech and futaba are both negative shift. But there is also some hitech receiver out there that are shift selectable to allow operation with Jr and airtronics transmitters. Airtronics and Jr are both positive shift.

Once again like I said I have not owned either the optic 6 or the eclipse 7 so I cannot comment there. I have seen a forum on here about the two radios. maybe if your lucky the radio would transmit with a shift selectable. I'm not sure on this but I think vaguely I might have heard something.

As for the spectra module using any channel you want is a nice option. But be aware that the spectra module will use a little more mah. simple fix use a battery with double the capacity of the original battery to get the same time on a single charge at the field. As far as Jr and Airtronics are concerned I have no idea if they have a synthesized radio (which I don't see why not) or not simple because the fact that I have never personally owned either radios. As far as my suggestion I would check into a Jr radio with synthesized equipment simply because of the fact that if you by a hitech radio then you are going to have to replace all of your existing radio receivers with negative shift receivers.
I hope this helps.
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Old 02-19-2005, 07:20 PM
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Default RE: Buying new computer tx

http://www.rcuniverse.com/forum/Hite...2620342/tm.htm
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Old 02-20-2005, 07:04 PM
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Default RE: Buying new computer tx

I was looking at the specs for the eclipse 7 and it has a fm shift modulations selectibility. so you can fly using all recievers either positive shift or negative shift you have to choose it in the modulation select mode.
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Old 02-21-2005, 02:06 PM
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Default RE: Buying new computer tx

I have not had the Optic 6 but have both the Prism and Eclipse and like them both. If I were buying a new one, I think I'd go with the Optic 6 as it is more user friendly. As to FM or PCM,, PCM is FM (frequency modulation)in all modern radios although you can still buy PPM using AM (amplitude modulation) Both PPM (sometimes called PWM) and PCM are the way the FM is modulated. FM is really a missnomer as the modulation used for both PPM and PCM is phase shift modulation in all our RC equipment. If you want more info, check out Torreypinesgulls.org.
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Old 02-21-2005, 02:11 PM
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famousdave
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Default RE: Buying new computer tx

This thread should be move to the general radio forum.. it will get a lot more replies there. Also -there is a lot of posts on this subject in many threads ...

DP
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