Help Required
 

Trying to help a friend sort out a raft of R.C. items. We are both relatively new to the hobby.
Some of the radio items are inscribed "Digital proportional" Others are shown as being "Dual Conversion"
Question 1. - What (If any) is the difference ?
.. .. 2 - Does one have any advantage over the other?
3 - Are they compatible in any way? ie: receivers/transmitters/crystals.

Hoping that someone can advise.

Thanks in anticipation.

Magpie.

Re: Help Required
 

Digital proportional are two entirely different things. It's not a difference between.

All the radios we use today are digital proportional. In the old days, we had receivers operatin with relays, reeds and analog proportional.

Digital is the way the signals are encoded - for example, digital as opposed to analog. That has nothing to do with dual conversion.

Proportional means simply that as your control stick on your transmitter moves, the servo which it controls moves a given amount and more as your control stick moves, in direct proportion to the amount of that transmitter control stick movement. MOve a bit, you get a little servo movement. Move twice as much, you get twice as much servoi movement.

Of course, with modern computer radios, you are easily able to change that relationship.

Dual conversion as opposed to single conversion, refers to the way the receiver handles the incoming signal when it's amplified and interference is rejected.

The crystals must be compatible with the specific system that you are using. Not all crystals will work in all receivers, for example. You will find this with JR, where some crystals, of identical frequency are in a black case while others are in a gray case. They are not interchangeable.

Re: Help Required
 

To simplify things as a beginner I would recommend that you spend some money and get a decent 2.4 ghz radio system.

It really doesn't matter which brand you get but it will save you alot of trouble with interference and channel usage.

Re: Help Required
 

Can you list which make and model of transmitter and receiver? This would help us answer your questions more effectively.

"Digital Proportional" equipment means that the servo moves directly in relationship to your control sticks. Only difference is if you have a switch, for example GEAR or FLAPS. In that case the servo would move to a preprogrammed position.

Dual Conversion is related to the receiver and is a description of how it filters the signals. D/C receivers are touted as having better reception, meaning they pick your signal out of the air and reject false or misleading noise more effectively. However, Singles work just as well if they are of a good design. In fact, some of the best Single Conversion equipment is able to do just as good a job.

Only concern for you is if the different components are compatible. Each manufacturer will have their system work a certain way, so in most cases you cannot mix and match from one to another. Same with Single and Dual Conversion receivers and crystals. You need to match a Dual Conversion Rx crystal with a Dual Conversion Rx, etc. It's also best you use the crystal from the receiver manufacturer to guarantee best performance.

There are exceptions to the above. Some receivers are made with the capability to receive and decode the signals from different makes of transmitters, Hitec and Berg amongst them. In some cases you need to flip a switch to receiver Airtronics/JR signals, or the other way for Futaba, Hitec, etc. More sophisticated, such as the Berg, will auto detect as long as you have the correct Berg Rx crystal to match the frequency of the transmitter.

Re: Help Required
 

Hi Cougar429, thanks for the speedy reply. We have quite an eclectic mix, as follows.
Futaba Skysport TX. Channel 52.
Futaba T7CAP TX. Channel 50.
Tower Hobbies Dual Conv. 7 channel RX - No Crystal
Hi-Tec 7 Channel RX. Dual Conv. ultra narrow band - no crystal
E-Sky RX 6Channel Digital proportional - no crystal.
E-Sky crystals (72.830 Channel 52) for RX and TX.
E-Sky crystals ((72-790 Channel 50) for RX.
GWS R6Nll RX. Naro Type.
GWS R4Pll/H RX. Pico Type.
Thanks again for your help.
Thought for today. If Isaac Newton's parents had remained childless, would our hobby be as interesting?

Re: Help Required
 

I know for a fact the ESKY receiver is compatible with Futaba, (If you open ESKY or EFlite transmitters the cases are likely to be Futaba anyway). Only problem is the ESKY receiver is what's called a "Parkflyer" type, meaning it has shorter range. Also, the ESKY receiver uses Single Conversion crystals. It looks like you already have the correct frequency crystals to tie to the Skysport and the 7CAP if you want.

What will happen with the Skysport 4 Ch transmitter is that you will only get Channels 1-4 working with the ESKY receiver if you plug in the Channel 52 crystal. It won't see channel data for 5 and 6 as they aren't there. If you use the Channel 50 crystal you can still use the 7CAP, it's just the 7th channel data will not be seen by the receiver as it cannot do anything with it. Channels 1-6 will function normally.

Hitec should also be compatible with Futaba. Don't know about the Tower Hobbies since you don't list a model number.

GWS makes receivers for both JR/Airtronics or Futaba/Hitec. Obviously the JR compatible receiver has a "J" sticker and Futaba compatible will be marked with an "F" sticker. The NARO is a 6 channel and PICO 4.

p.s. The ESKY transmitter crystal should also work in the Skysport as it has a plug in crystal, rather than the later model 7CAP module type. The 7CAP is a programmable radio set up primarily for airplanes, (meaning the switches are marked for airplane functions rather than for helis) and will have a lot more options for control throws and direction, exponential and other features.

My only concern is with the age of the transmitters in relation to their battery life. I would recommend you cycle and check the batteries or look to replace them.

NOTE: For all intents the GWS receivers are also short-range Parkflyer types. I would recommend if you intend to fly larger airplanes with a normal flight regime the best receiver of the bunch you listed would be the Hitec. Go online and look for a Hitec crystal to match the transmitter frequency you intend to use.

Re: Help Required
 

Thanks again for the wealth of information.
Good winds, and safe flying.
Magpie.

Re: Help Required
 

7C transmitter as master -> make sure it's switched to PPM not PCM
Skysport as buddy box (on a cable)(or second TX)

These are both full range receivers, both likely PPM/FM
Hitec needs Hitec Rx crystal to match Tx
Tower hobbies should be Futaba compatible, so may need a Futaba Or Tower Rx xtal not sure here and the tower website doesn't show tower xtals and only shows this Rx as included with a six channel radio package.


These are pretty much all parkflyer receivers unless it states dual conversion

You will need battery packs, switch harnesses, and servos to suit the aircraft.

Re: Help Required
 

As soon as I shut off the PC last night I realized I forgot to mention about PCM and PPM.

The Skysport and all the receivers listed are only able to work with the standard PPM signal coding. Your 7C has the capability of encoding the signals in PCM as well as PPM. PCM coding is another form of signal algorithm that requires a unique Futaba PCM receiver to decode. It will have a "P" in the ident name. For example 146iP or 138DP. PPM types will have an "F", such as a 138DF.

To change from one to another on the 7C you need to go into the PARAMETERS page and set PPM, then turn the transmitter off and on again to set that mode.