Futaba FP-T7UAF transmitter conversion

Shout here if you need any help!
Maybe you need a plan - just shout
MJF
Posts: 81
Joined: 12 Jun 2018, 15:22
Location: Ontario Canada

Futaba FP-T7UAF transmitter conversion

Post by MJF »

I have this older but still functional Futaba transmitter that I would like to put a FrSky XHT module in. I have never changed over a standard transmitter in the past and do want to mess it up (i.e. let the smoke out)
Although it is on a still legitimate 72MHz frequency channel most clubs in our area frown on their use due to "age" and being on 72MHz.
Typical older module equipped Futaba.
Typical older module equipped Futaba.
I removed the back of the transmitter to locate the board & contacts for the plug in module and found the T853B board where the module plugs into.
I am sure the blue wire is the PPM line, Red positive, I do not know what the yellow wire is for??, Black is ground, White is the antenna and the other Black is also ground.
The T853B board with the blurry pins is where the module plugs into. I was planning on removing the header with the long pins and soldering the 3 XHT wires to the board. Removing the insides of the plug in module box, modifying it to fit the bind board in it
The T853B board with the blurry pins is where the module plugs into. I was planning on removing the header with the long pins and soldering the 3 XHT wires to the board. Removing the insides of the plug in module box, modifying it to fit the bind board in it
Questions What is the yellow for? Should I remove it or leave it in place as the XHT module leaves the pin vacant?
Should I snip off the white wires for the antenna or can I leave them in place as the XHT has no connection to that pin either.

Any input appreciated.

Thanks


Mike F
User avatar
Wayne_H
Posts: 809
Joined: 17 Feb 2018, 05:26
Location: Temora, NSW. Australia
Contact:

Re: Futaba FP-T7UAF transmitter conversion

Post by Wayne_H »

Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
MJF
Posts: 81
Joined: 12 Jun 2018, 15:22
Location: Ontario Canada

Re: Futaba FP-T7UAF transmitter conversion

Post by MJF »

Thanks Wayne.

Looks like I can simply connect the XHT PPM, Positive and Negative wires and leave the rest alone.
Thought there would be more to it than that.


Mike F
User avatar
Wayne_H
Posts: 809
Joined: 17 Feb 2018, 05:26
Location: Temora, NSW. Australia
Contact:

Re: Futaba FP-T7UAF transmitter conversion

Post by Wayne_H »

Some manufacturers use additional pins for functions such as channel check (is frequency clear before transmitting), RF signal strength, telemetry, etc. Best is try the simple approach first - I'm sure it will work. :)

Since I don't have any Futaba txs fitted with modules, I can't check anything myself. Others with Futaba modules will chime in as necessary, I'm sure ;)
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
MJF
Posts: 81
Joined: 12 Jun 2018, 15:22
Location: Ontario Canada

Re: Futaba FP-T7UAF transmitter conversion

Post by MJF »

Phil_G wrote: 20 Jan 2021, 10:40 Is that a standard Futaba module? if so I'd find a DFT which would just slot in, job jobbed :D
Hi Phil

Yes that is a standard Futaba module. I did look around for a DFT plug in unit to no avail. When I press the order button I get a message saying either out of stock or discontinued. Swap meets have been on hold for some time due to Corona. I thought I would try the XHT board for now.

In the mean time I did connect my spare XHT to the PPM, Pos. & Ground leaving the yellow and white wires in place and it did bind to the V8R7-II receiver and the sticks operated the servos. I was not sure if doing this I might cause damage in the long term to what ever the yellow wire was doing with the old module.

The purpose of converting this old radio was to have one transmitting the ACCST protocol. This would allow me to test fly my new models intended to operate either on simulated reeds or multi function single channel on proportional for the first flights.
User avatar
Wayne_H
Posts: 809
Joined: 17 Feb 2018, 05:26
Location: Temora, NSW. Australia
Contact:

Re: Futaba FP-T7UAF transmitter conversion

Post by Wayne_H »

If you can't pick up a genuine Futaba compatible Frsky module, then depending on how much you really want Frsky functionality in a Futaba-compatible module, another option could be to use a Corona Futaba-compatible module such as the Corona CT8F - e.g. https://www.aliexpress.com/item/1005001 ... 6062%23774

& reprogram it using Martin's code - see thread viewtopic.php?f=42&t=1092&start=50 - from one of Martin's posts (on page 6) of that thread "....The transmitter modules I know work are the CT8F and CT8J - ..."
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
solar
Posts: 6
Joined: 12 Feb 2021, 17:25

Re: Futaba FP-T7UAF transmitter conversion

Post by solar »

MJF wrote: 20 Jan 2021, 01:47
Although it is on a still legitimate 72MHz frequency channel most clubs in our area frown on their use due to "age" and being on 72MHz.
I have an almost identical Tx bought abroad and assuming it was illegal in UK I was also thinking of converting using the FrSky XHT. It's on Channel 40 of 72MHz. I was surprised to hear you say it may be legal. For the purposes of non club use (I don't fly planes) can I use it and is there any licensing needed?
Last edited by solar on 13 Feb 2021, 18:02, edited 1 time in total.
solar
Posts: 6
Joined: 12 Feb 2021, 17:25

Re: Futaba FP-T7UAF transmitter conversion

Post by solar »

Wayne_H wrote: 20 Jan 2021, 23:39 If you can't pick up a genuine Futaba compatible Frsky module, then depending on how much you really want Frsky functionality in a Futaba-compatible module, another option could be to use a Corona Futaba-compatible module such as the Corona CT8F - e.g. https://www.aliexpress.com/item/1005001 ... 6062%23774

Sorry I am new to all this but what happens if one uses the Corona module and instead of reprogramming it use a Corona Rx like https://www.aliexpress.com/item/1005001 ... 15607%2393 which are cheaper than FrSky ones?
MJF
Posts: 81
Joined: 12 Jun 2018, 15:22
Location: Ontario Canada

Re: Futaba FP-T7UAF transmitter conversion

Post by MJF »

Hello Solar

Regarding my Futaba FP-T7UAF transmitter being on 72 MHz and still being on a legal frequency it is important to note that I am located in Ontario Canada. The Model Aeronautics Association of Canada is our "governing" body as far as modelling is concerned. They work closely with numerous Government agencies such as Industry Canada to keep us informed and on the straight and narrow.
All of the 72 MHz numbered channels on narrow band are still OK to use in Canada but a lot of clubs no longer welcome them.
I have some older wide band RC sets on 72 MHz such as 72.160 (blue/white) and 72.960 (Yellow / White) as well as some others are no longer legal to use (I still have three of these but do not use them).

I do not know where you are located in the world but I would bet if in Europe your rules would be different than ours. I know for instance that in England they used 35MHz (and some others on HAM bands) . Hopefully someone from your part of the world can clarify what you can use and what not to use.

I have attached a copy of the permitted approved frequencies for use in Canada. See page 2 of the document for a list of transmitter frequencies for model control and page 3 for FPV and video transmission.
Again this is Canada and maybe USA.

I have put a FrSky XHT module in my Futaba FP-T7UAF transmitter and it works perfectly. I did not post the conversion as I thought it may be boring to most - I can take some photos & post if there is any interest. It seems that plug in 2.4 Modules for this transmitter are more widely available other than here!!!

Mike F
MAAC Safety Document (MSD) 17 - Radio Spectrum.pdf
(418.07 KiB) Downloaded 118 times
User avatar
Wayne_H
Posts: 809
Joined: 17 Feb 2018, 05:26
Location: Temora, NSW. Australia
Contact:

Re: Futaba FP-T7UAF transmitter conversion

Post by Wayne_H »

solar wrote: 13 Feb 2021, 17:44 Sorry I am new to all this but what happens if one uses the Corona module and instead of reprogramming it use a Corona Rx like https://www.aliexpress.com/item/1005001 ... 15607%2393 which are cheaper than FrSky ones?
That would work fine - just means your using Corona protocol so have to use Corona (compatible) Rx's. Just follow the instructions that come with the Corona module for binding with the Rx.

My reference to reprogramming using Martin's procedure was to offer an alternative if you HAD to have the Frsky protocol but couldn't source a Futaba compatible Frsky tx module.

If you’re not tied to using Frsky, then much simpler & easier to just "plug n play" using Corona's Futaba compatible Tx module & Rx's.

Let us all know how you get on.
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
Post Reply