RunRyder RC
 3  Topic Subscribe
WATCH
 1 page 692 views
Scorpion Power Scorpion Power
HelicopterBeginners Corner › FM or PCM ?
03-10-2003 08:19 PM  14 years agoPost 1
BillCt

rrNovice

Connecticut

My Posts: All  Forum  Topic

Not sure which to buy. I am new to heli and not sure which to buy. I am buying the JR 8103 but not sure if I need to spend $100 more for the PCM mod. Not to sure of the difference.

Thanks BillCT

PM  EMAIL  Attn:RR  Quote
03-10-2003 09:23 PM  14 years agoPost 2
5zigendes

rrApprentice

Orange County, ca

My Posts: All  Forum  Topic

from what i remeber, pcm has failsafe and fm does not. failsafe can come in handy sometimes.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-10-2003 09:30 PM  14 years agoPost 3
mrNoodles

rrProfessor

Borlänge, Sweden

My Posts: All  Forum  Topic

FM is PCM, the "opposite" of PCM is PPM.

/Fredrik
'Hm now I just have to find out where to connect the GV1 sensor to the Jazz80 ESC.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-10-2003 09:31 PM  14 years agoPost 4
midi0101

rrNovice

Calgary, Alberta,​Canada

My Posts: All  Forum  Topic

Well, yes failsafe can come in handy....but it also can kill people if not setup properly.....anyway, the difference is the modulation of the signal. You get a better resolution with pcm (pcm1024 (todays pcm standard, I believe) has 1024 steps of resolution. I am not quite sure how fm compares to that (some electronic literate care to comment ?), but overall, pcm is more excact.....whether or not you 'need' pcm....well, I don't know...I fly fm, and that will do for the forseable future..

Michael

PM  EMAIL  Attn:RR  Quote
03-10-2003 09:37 PM  14 years agoPost 5
The_Dave

rrVeteran

Las Vegas / Pahrump,​Nevada

My Posts: All  Forum  Topic

FM is PCM, the "opposite" of PCM is PPM.
Actually, PCM and PPM both transmit on the FM band. I believe one is digital (PCM) and one is analog (PPM).

Mark McAlpine - 2005 - We will never forget.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
03-10-2003 10:02 PM  14 years agoPost 6
vitek

rrKey Veteran

Corvallis, OR

My Posts: All  Forum  Topic

The transmitter and module are the same either way (PCM or FM). The difference is the servos and the receiver that you get. There are several different sets that you can get these days. These are just 2 of the many.

JRP8622** Helicopter FM
JRP8653** Helicopter PCM

The 8622** sets come with 5 537 servos and the R549 RX, the 8653 sets come with 5 811 ditigal servos and a R649 RX. There are also cheaper FM sets that come with the R700 RX. Here are the servo specs.

JR 537 Standard Servo Specifications
Torque: .43 oz/in@4.8V
Speed: .25 sec/60°
Weight: 1.58 oz

JR 811 Digital Servo Specifications
Torque: .54 oz/in@4.8V
Speed: .18 sec./60°
Weight: 1.44 oz

Most people (including myself) would recommend against putting the 537s or even an FM RX in a 60 size helicopter. If you are going to be putting this into a 30 size heli, you'd be fine to get the FM set.

You will be saving yourself a little bit of money if you get the PCM stuff now, as you will most likely upgrade to PCM and digital servos over time.

PM  EMAIL  GALLERY  Attn:RR  Quote
03-10-2003 10:13 PM  14 years agoPost 7
Chef

rrApprentice

Derbyshire. United​Kingdom

My Posts: All  Forum  Topic

PM  EMAIL  GALLERY  Attn:RR  Quote
03-10-2003 10:18 PM  14 years agoPost 8
mrNoodles

rrProfessor

Borlänge, Sweden

My Posts: All  Forum  Topic

Dave

That was what I meant! That both of them transmits on FM band.

/Fredrik
'Hm now I just have to find out where to connect the GV1 sensor to the Jazz80 ESC.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
WATCH
 1 page 692 views
Scorpion Power Scorpion Power
HelicopterBeginners Corner › FM or PCM ?
 Print TOPIC  Make Suggestion 

 3  Topic Subscribe

Friday, November 24 - 6:45 pm - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online