FrSky V8HT DIY 2.4 Tx Module - Installation

[sweli]

I have been trialing some 2.4 Eflite modules in radios with some bugs to work out. It's time to move on from FM. My kids are (a little) more careful with the radios. And one of my rigs with a lot of tube work is glitchy no matter what FM Rx or Tx I use.

In the meantime, I ordered two FrSky V8HT DIY 2.4 Tx modules from Hobbyking.
V8HT(discontinued)-2.4GHz V8 Series-V8 Transmit-Product Show-Products-FrSky Electronic Co.,Ltd
It is now replaced by a newer module, and is out of stock.
FrSky V8HT 2.4Ghz DIY Module





I also ordered two Rx(s) to start with.
FrSky V8R4-II 2.4Ghz 4CH Receiver

[sweli]

In my Futaba T3PDF radios, this is a breeze
Can you say, Red=V+, Black=V- and White=PPM/PWM !

Cut the wires, removed the FM module PCB, which left a lot of space to secure the new FrSky module inside the caseback.
I modified the old antenna guide to hold the new threaded antenna mount.

[sweli]

Have to say the newer antenna looks nice, but weirdly out of place on this older radio.


The teach button and status LED board fit perfectly in the old FM crystal window.

[sweli]

TX and it's 2" antenna are in a waterproof ABS box under the rigs hood.
In the glitchy tuber, I was able to control the rig 40ft away through two cement walls.
The FM radio would have been glitchy even with the antenna half way up!

[dirtslow]

Hey, How did you find out the radio is PPM? I am trying to do the same with my old airtronics cs3p.

thanks

[sweli]

Wow, that's an early one.
FM is either PPM or PCM. I don't believe there are many PCM radios out there, and most of those were probably 4+channel stick radios for flight.

Understanding Spread Spectrum Radios, PCM Radios, FM Radios, and AM radios.

Have you pulled the case appart? Are there seperate control and transmit PCBs with three wires between them?

[td-civ]

all radios are ppm but some radios can be set to pcm or ppm you just have to go in to your programing of your radio and set it to ppm thats all i have done this mod to over 40 old style radios in many makes and models

[dirtslow]

Oops, it is actually a cs2p not 3. It has a FM 27 mhz module on top. Was one of the top radios in the '90s. I have taken it partially apart. It has many wires from the module not just the blk/whit/red trio.

I am not knowledgeable enough to decipher. I will try again.

thanks

[sweli]

I have found a few 5 wire systems that people have discussed on various forums.

Does one of the five wires lead to the antenna?
Problem is he PPM line will appear to be a V+ line to the average multi meter.
I was lucky enough on the Futaba to have 3 wires, but also that the 12v from my 3s lipo was also what was powering the old FM module. So even with a multi meter, it was discernible at 12v, from the 3.7v PPM line.


FrSky DIY module to old Futaba radio? - RC Groups

Frsky on hitec flash 5x - Page 2 - RC Groups

Corona 2.4GHz diy kit - convert old radios to 2.4GHz - R/C Tech Forums

[td-civ]

ok it dont mean anything if the radio is 5 or 3 line you only use 3 lines

power

ground

ppm line

as long as you can find them your good the radio will work 100%

[sweli]

Round 2

This one I left the FM transmitter in and also installed the 2.4 module.
I bought a 2P2T slide switch from Rat Shack that cuts the V+ and PPM signal.
I have LOTS of Novak FM Synth modules and not enough radios to change all my waterproof rigs over to 2.4 yet.

Guts: Selector switch is below module, antenna above. LED and Bind button are on the right. FM board still on the main board.


I put the selector switch in a downward position (in case I'm out in the rain) that won't get bumped. Throw of the switch coordinates with the antenna position.


Mounted the LED and Bind button behind a rubber strip that has a LED diffuser built in.



Might try and use an old 3PM FM antenna I have that is shorter than this one.