Hi - Anyone on here into RC planes? I'm just starting out and have bought a Futaba FF7super Tx which is PCM/PPM selectable.

I now need a matching Rx but do I HAVE to use the Futaba ones stated in the Tx instruction book (R129DP, R137GP,R149DP) or can I use other makes. If so, what is the criteria for a suitable Rx? I see some advertised as 'Dual Conversion Type' does this mean they can be used for both PCM and PPM or does this mean they can use ceramic and crystal xtals (or what????)

 

Looking for some help - Dave

My brother-in-law has several RC planes so i will ask him and get back to you. He's actually selling some so he might have what you need.

My brother-in-law has several RC planes so i will ask him and get back to you. He's actually selling some so he might have what you need.

 

Thanks, bigsss, I'll keep my fingers crossed.

You can use aftermarket recievers , IIRC if you buy a ppm reciever make sure you have a ppm crystal installed as a pcm one won,t work in it :confused: .

Early sets were all ppm , most out today are ppm and pcm so they can be used with earlier recievers.

A pcm set sends the signal twice from your transmitter to the reciever so if the reciever doesn,t recieve the second mirrored part of the signal it won,t follow the command , it,s designed like this to cut down on inteference problems cos any inteference would only be one signal recieved so the reciever won,t tell the servo,s to move as it,s not a legitimate command .

If you can understand this your doing better than me :headvswal:

The only probs i,ve had with aftermarket ones is some glitching when used in electric planes :cry: HTH

Meant to say , dual conversion means it,s ppm and pcm compatible :hyper:

You can use aftermarket recievers , IIRC if you buy a ppm reciever make sure you have a ppm crystal installed as a pcm one won,t work in it :confused: .

Early sets were all ppm , most out today are ppm and pcm so they can be used with earlier recievers.

A pcm set sends the signal twice from your transmitter to the reciever so if the reciever doesn,t recieve the second mirrored part of the signal it won,t follow the command , it,s designed like this to cut down on inteference problems cos any inteference would only be one signal recieved so the reciever won,t tell the servo,s to move as it,s not a legitimate command .

If you can understand this your doing better than me :headvswal:

The only probs i,ve had with aftermarket ones is some glitching when used in electric planes :cry: HTH

Meant to say , dual conversion means it,s ppm and pcm compatible :hyper:

 

Hi Boldy - Many thanks for your help....you've filled a lot of holes in my knowledge. Your clear description of PCM has at last enabled me to understand what it is, something several worldwide web sites I have perused have been unable to do.

At the moment I have my switchable Tx set for PPM and am using a PPM Rx and crystals...it all seems to be working OK. The information you have given makes me want to take advantage of the PCM functions even more so I will now start looking for a 'dual conversion' Rx.

I've had a bad start as there was one on eBay being sold as 'dual conversion' but when I emailed the seller he said 'sorry it is only PPM'..you can't trust anyone can you!

Can I assume from what you say that any aftermarket 'dual conversion' Rx should be OK? (Provided, of course, that it has sufficient channels....in my case a minimum of seven).

 

Thanks again for your help - Dave

Yes bud , aftermarket dual conversion recievers should work fine and the good thing is there a damn site cheaper than Futaba ond other makes :hyper: :hyper:

All this talk of models actually made me go in the workshop and clean this one up ready to sell , can,t fit it in my car , had a carlton estate before the zed :x:

It,s a 1/4 scale Protech Giles GS600 , 73inch span , fantastic plane but i,m more into funfly,s , sommat i can chuck around the sky and not worry if it hits terra firma :nono:

PPM will be fine, PCM is normally used for larger models. They also incorperate a fail safe, so if loss of signal, it will set the servos to a set position, normally so it stalls and spials down. You wouldnt want a large model just flying off into the distance!

 

You can use other makes and I do, in my gliders, but for my more expensive electric models, I use all the same make, inc crystal. You can get a lot of interfernace and using all the same makes ensures the best signals possible. Its only a few quid more, but on a £700 plane I think its worth it!!!!

 

You know that plane I was looking to sell you saw. That crashed the other day due to interferance, DOH!!!!!!

After speaking to my brother-in-law he basically told me much the same of what rodders and boldy have already said so beat me to it. He did suggest to find a local flying club as this is what he did as the info he got from its members was invaluable and also for cheap second hand parts and remotes etc.

Thanks Guys, you are all being a great help. :bow:

 

Sorry your plane got pranged Rodders.

 

A nice looking model, Boldy, I've bought a second hand 72" wingspan 'custom designed' trainer model which is pretty robust (heavy) and a bit scruffy but it wasn't a lot of money and should hopefully see me through my early training days.

 

The one thing that's still confusing me is the term 'dual conversion' as some dual conversion eBay ads say PPM and some say PCM. I thought dual meant suitable for both. Does this mean that there are PCM specific receivers and would these be cheaper than the dual versions?

I wouldn,t swear on it bud but i always thought any pcm reciever was already ppm compatible :confused:

Probably worth checking with a shop though .

Happy landings :hyper:

Dual conversion and single conversion is nothing to do with PPM and PCM.

 

Dual conversion receviers have better interference rejection than single conversion. Dual conversion come in both PPM and PCM as do single conversion come in PPM/PCM.

DOnt forget DC receivers need a DC crystal!!

 

You will find PCM cost more too.

Dual conversion and single conversion is nothing to do with PPM and PCM.

 

Dual conversion receviers have better interference rejection than single conversion. Dual conversion come in both PPM and PCM as do single conversion come in PPM/PCM.

DOnt forget DC receivers need a DC crystal!!

 

You will find PCM cost more too.

 

Oh dear.....getting more confused :confused:

What does dual conversion mean then, Rodders, and what the heck is DC?

 

Dave

 

EDIT - Sorry, DC obviously means dual conversion...I'm just thick :slap:

As above mate, DC can keep out interefence better than SC.

 

So if you have a bigger, yours isnt big, model that you are going to fly further away from you, then DC would be better than SC.

As above mate, DC can keep out interefence better than SC.

 

So if you have a bigger, yours isnt big, model that you are going to fly further away from you, then DC would be better than SC.

 

Thanks Rodders, I now understand that DC keeps out interference better but how does it do this, and does the Tx/Rx have to have a special xtal?

DC receviers require a specific DC xtal. SC like wise wouldnt work with w DC xtal.

 

DC has some crazy electronic sh1t that I know nothing about inside that does it!

 

Tx and Rx crystals are different too anyway. You must make sure you dont get them mixed up!

 

Im not sure if theres DC/SC Tx xtals though. It might only be down to the Tx. Not 100% sure mate.