How to chose radio transmitter/receiver

[demands]

Hi all,

I would very much appriciate help in chosing a radio to use for my tricopter build.
I'm building my first *copter, and want a radio which is "future-proof" though not to expensive.
I would also like a receiver which provides PPM directly, so I don't need to hack/convert it...

So far I haven't found any good lists of transmitter/receivers, just a bunch of hacks and converters one could use to get PPM from different receivers.
Isn't there any PPM ready receivers out there? Been looking at HK, though I can't find receivers stating they do PPM out...
How many channels is minimum/recommended for tri- and quadcopters (and in case of additional channels for future triggers etc, how many should I go for).
Should I go for 35/72MHz or 2.4GHz?? Pros/Cons??
Can someone explain "synthesized" (and pro/con)??
Preferably, I don't want to spend more than 400$ on a complete kit (transmitter/receiver), less if possible.

I guess what I'm asking for is a "radio wrap-up" from someone with a bit of knowledge/experience...
It's a jungle out there

PS. Of course I'm building with MultiWii, which is why I'm posting in this forum
But I've looked through rcgroups.com as well, and I'm still (even more) confused

//demands

[captaingeek]

since your just starting maybe go with a cheapy. you can get the flysky 6 channel for about $50 or the flysky 8 channel for around $70. both are good readios and come with an RX.

[demands]

Thanks captaingeek,

I've looked at the FlySky's you suggested. But I haven't found any retailer shipping to Sweden...
As of right now, I'm looking at HK, and have a couple of suggestions myself (maybe bad ones, I don't know).

I would appriciate comments/rating on the following, all found on HK.
Is there anyone I should avoid?
Which is "most bang for the buck"?
And, ultimately, will they all get the job done with a MultiWiiCopter??

• Turnigy 9X 9Ch Transmitter w/ Module & 8ch Receiver (Mode 2) (v2 Firmware) - 53,79$ - http://www.hobbyking.com/hobbycity/stor ... ware_.html
• Hobby King 2.4Ghz 6Ch Tx & Rx V2 (Mode 2) - 22,99$ - http://www.hobbyking.com/hobbycity/stor ... de_2_.html
• HK-7X 2.4Ghz 7ch w/ 5 Model Memory TX & RX V2 (Mode 2) - 49,99$ - http://www.hobbyking.com/hobbycity/stor ... de_2_.html
• HobbyKing HK6DF 2.4Ghz FHSS 6Ch Tx & Rx (Mode 2) - 28,41$ - http://www.hobbyking.com/hobbycity/stor ... de_2_.html
• Futaba 6EX 2.4GHZ FAAST Radio System w/R617FS Receiver (Mode 2) - 169,99 - http://www.hobbyking.com/hobbycity/stor ... de_2_.html

They're listed in the order I think I'd get most bang for the buck. I guess the Futaba at the bottom is "the best", but it's also a lot more expensive than the rest. It's all the transmitters I've found <400$...

[brink094]

I started with the Hobby King 2.4Ghz 6Ch, it works but you need to order the separate usb cable and use a computer program to change settings. Advantage is that the receiver has a ppm sum signal on the bat connector. This radio also feels a bit cheap, I bought this radio first because the 9X was always out of stock.

Quickly I upgraded to the Turnigy 9X, this radio feels a lot better quality wise and it has more channels for future use. Programming can be done without a computer. This radio is also compatible with the receiver of the HK 6ch radio, so if you order this receiver:
http://www.hobbyking.com/hobbyking/stor ... Ch_V2.html
You get a lighter receiver with a ppm signal on the bat connector! I don't think the turnigy 8ch receiver has a ppm signal.

Another reason to get the 9X is that you can load your own firmware which upgrades it to a really powerful radio:
http://code.google.com/p/er9x/
http://www.rcgroups.com/forums/showthread.php?t=1266162
Easiest way to update the firmware by installing this programmer and back light kit:
http://www.smartieparts.com/shop/index. ... fadcd35cba
The default firmware has some quirks and bugs but will work fine for a tricopter so you do not have to upgrade to the er9x firmware if you don't want to.

My advice would be to skip the cheap HobbyKing brand radio's and go for the Turnigy 9X and order the HK-TR6A receiver for the ppm sum signal.

[EOSBandi]

I started with the Hobby King 2.4Ghz 6Ch, it works but you need to order the separate usb cable and use a computer program to change settings. Advantage is that the receiver has a ppm sum signal on the bat connector. This radio also feels a bit cheap, I bought this radio first because the 9X was always out of stock.

Quickly I upgraded to the Turnigy 9X, this radio feels a lot better quality wise and it has more channels for future use. Programming can be done without a computer. This radio is also compatible with the receiver of the HK 6ch radio, so if you order this receiver:
http://www.hobbyking.com/hobbyking/stor ... Ch_V2.html
You get a lighter receiver with a ppm signal on the bat connector! I don't think the turnigy 8ch receiver has a ppm signal.

Another reason to get the 9X is that you can load your own firmware which upgrades it to a really powerful radio:
http://code.google.com/p/er9x/
http://www.rcgroups.com/forums/showthread.php?t=1266162
Easiest way to update the firmware by installing this programmer and back light kit:
http://www.smartieparts.com/shop/index. ... fadcd35cba
The default firmware has some quirks and bugs but will work fine for a tricopter so you do not have to upgrade to the er9x firmware if you don't want to.

My advice would be to skip the cheap HobbyKing brand radio's and go for the Turnigy 9X and order the HK-TR6A receiver for the ppm sum signal.

If you are a DIY kind of guy, then Turnigy 9Xv2 is your radio. You can replace the TX module with a really good FRSKY TX and put the er9x firmware on the radio. If you choose FrSky with telemetry you can even see telemetry data on the TX display. For around $100 and some diy work you will get a system which costs 5+ hundreds from brands.

http://www.hobbyking.com/hobbyking/stor ... ware_.html $53.69
http://www.hobbyking.com/hobbyking/stor ... duct=16720 - BackLight for Turnigy Tx9 $4.99
http://www.hobbyking.com/hobbyking/stor ... duct=14353 - FRSKY DIY TX module without telemetry $14.95
http://www.hobbyking.com/hobbyking/stor ... duct=17205 - FRSKY DIY TX module with telemetry $22.14

http://www.hobbyking.com/hobbyking/stor ... duct=14350 - FRSKY 8ch receiver without telemetry $18.93
http://www.hobbyking.com/hobbyking/stor ... duct=14356 - FRSKY 8ch receiver with telemetry $23.67

[captaingeek]

i have both the flysky th6 (same as hk 6ch v1) and the flysky 9ch v2 *same as t9x). both are very good radios.

i'm interested in using the ppm signal on the bat connector. anyone know about that?

[brink094]

To use the ppm sum signal you only have to move the throttle wire on your receiver (ch3) to the bat connector and disconnect all the other wires. Just one wire is needed between your receiver and the arduino

Then in the software uncomment one of the SERIAL_PPM_SUM lines. You may have to change the order of the channels, this configuration works for my Turnigy 9x with er9x firmware:

Code: Select all

/* The following lines apply only for specific receiver with only one PPM sum signal, on digital PIN 2
   IF YOUR RECEIVER IS NOT CONCERNED, DON'T UNCOMMENT ANYTHING. Note this is mandatory for a Y6 setup on a promini
   Select the right line depending on your radio brand. Feel free to modify the order in your PPM order is different */
//#define SERIAL_SUM_PPM         PITCH,YAW,THROTTLE,ROLL,AUX1,AUX2,CAMPITCH,CAMROLL //For Graupner/Spektrum
#define SERIAL_SUM_PPM         ROLL,PITCH,THROTTLE,YAW,AUX1,AUX2,CAMPITCH,CAMROLL //For Robe/Hitec/Futaba
//#define SERIAL_SUM_PPM         PITCH,ROLL,THROTTLE,YAW,AUX1,AUX2,CAMPITCH,CAMROLL //For some Hitec/Sanwa/Others

[demands]

Thank you very much guys!
This weeks shopping list from HK looks like this (ordered yesterday):

• Turnigy 9X 9Ch Transmitter w/ Module & 8ch Receiver (Mode 2) (v2 Firmware)
• Turnigy 9X LCD Backlight Kit - Blue (DIY)
• FrSky DHT 8ch DIY Telemetry Compatible Transmitter Module
• FrSky D8R-II 2.4Ghz 8CH Receiver with Telemetery
• FrSky USB Cable
• FrSky Battery Voltage Sensor - FrSky Telemetry System

[natael]

Hi,
I'm digging out this post instead of creating a new one for the same question. I was looking for information on the Turnigy 9x (i'm a noob at rc, not in electronics/programming, I'm just at the beginning of a DIY tricopter), which got me there. I wondered seeing that last reply : if I go for the Turnigy 9x, and if I get the separate" FrSky DHT 8ch DIY Telemetry Compatible Transmitter Module", can't i simply get the Turnigy offer that comes without the native transmitter module : http://www.hobbyking.com/hobbyking/stor ... ware_.html ??

Now, in the case of that particular radio, what difference will it make for a noob choosing between mode 1 and mode 2 ?

Thanks for your help