Hi,
I'm wanting to know if I can use a Jr flight pack with my Futaba transmitter. I under stand futaba has a negative shift and Jr a positive shift. I'm not sure what that is thou.


Thanks for the help

thetoad

JR servos work with futaba receivers and transmitters but a JR receiver will not work with a futaba transmitter.

You'd need a Futaba receiver and buy the JR servos seperately.

If you get the new JR receiver that allows you to select the 'shift' you can use it. If not, you can't. I just bought a new JR sport 120 pack and it came with a shift selectable RX. You cannot use a positive-shift RX with a Futaba TX.

Good Luck!!!

Some manufacturers use positive shift and some use negative shift. Manufacturers are now providing receivers which are "Shift Selectable". Futaba, HiTec and Tower Hobbies are Negative Shift and JR and Airtronics are Positive Shift. Both HiTec and JR are providers of "Shift Selectable" receivers. Why an industry standard wasn't settled on is anyones guess. I think at first, the manufacturers thought; Well, if we pick something which is exclusionary, only our products can be used with it! Then they found out; Well, we've used something which is exclusionary and because of this, our products can't be used with other's.

What "Shift" is, is not known by me!

PPM mean Pulse Position Modulation. IAW you are changing the POSITION of the pulse in the data stream "word" that is transmitted. Each control or "channel" is always in the same relative order or transmission but the "time" when the pulse starts can be shifted forward or backward by a few micro-seconds. This is know as positive or negative shift.

Earlier sets used PWM or Pulse Width Modulation. All pulses started at a uniform time but the pulse widths for each channel varied.

PCM is an entirely coded signal not like either of the above and is based (very basically) on the presence or absence of data bits in a binary code for each channel.

JR sells RXs for Futaba/Hitec/Tower shift transmitters. I'm using probably the best value in an ultra light RX around, the RS6UL, with my remaining Futaba TX. They sell the RS6UL two ways. One is negative and one is positive.... no jumpers to set.

Tower doesn't sell them but Horizon does. http://www.horizonhobby.com/Products...rodID=JSP40015

And most LHS will have that JR counter top display with all the SPORT line servos, batteries, connectors, switches, and RXs sitting somewhere in their store. I just bought another RS6UL for less than $50 at the LHS off one of those displays. They're an excellent, reliable, long range RX and the price is good.

Bruce, thanks for the answer to my statement about not knowing what "Shift" is. We could go on to say the PPM is another name for FM and PCM = Pulse Code Modulation. Now, ain't I smart? None of this helps me fly better, though! Now, why is that?

While you could say PPM = FM and PCM = Pulse Code Modulation, it wouldn't really be saying anything since PCM is also FM!

Ooh Chuckie, you've been reading again. You're right. PCM is pulse code modulated FM and PPM is PPM FM

Yes, and I had even had my morning coffee!

thanks for the help, the pack I was looking at does say universal in the tech. notes

thanks

I'm sure glad Chuck got his morning coffee, because he can be a real bear without it, & they call me Grumpy!![8D]

About a year or so ago, when JR was advertising their latest transmitter, I asked the tech rep -- here on RCU -- just when JR would add the feature of "Shift'Select" into their transmitters. My Airtronics' Stylus -- rather old computer technology -- has that selection in the program, My older Hitec 7 channel has that feature. My JRs do not. I have a number of the Hitec receivers with the feature on the receiver however that costs one channel of the receiver.

JR replied that JR DOES NOT WANT THEIR CUSTOMERS MIXING ANY OTHER RADIO ITEMS WITH THEIR JR TRANSMITTERS!!!

Sorry JR, but I do and I will as long as my current 2 JR transmitters function. They will not be replaced by like items.

I don't remember saying PCM wasn't FM; and although I stated I didn't know what "Shift" was, a more accurate response would have been; I don't care what "Shift" is! Sorry for the confusion, my bad!

The only important aspect of the question is that the "Shifts" be matched.

I build and fly R/C model airplanes. I lack interest in the inner workings of how radio's work. I am interested in not wasting money buying equipment that won't work together.