Futaba RF Module Pinout

[jcaywood]

I'm working on a personal project and I'm trying to figure out the middle pin of this module(FP-TP-FM), so far I've come up with(looking at the back of the radio, with the module board installed, and calling the left most pin "1")

1 - PCM/PPM Signal from Radio
2 - V+
3 - ??
4 - GND
5 - RF Out

I'm not sure what pin 3 is, the signal on it looks like a weak copy of the RF out signal, is it perhaps the pin used to indicate to the radio that the module is plugged in? I'm going to throw it on a better scope at work and see what I come up with. Any help would be greatly appreciated.

[Bruce Abbott]

Pin 3 is the RF output indicator. It pulls down to ground when RF is detected at the collector of the final amp.

[jcaywood]

Thank you very much!

[icedog]

Hi , Bruce
Do you have the full schematic of futaba rf module?

[Bruce Abbott]

I have traced out the circuit of 60MHz unit, but only the part posted above has been translated into electronic form (the original drawing is very messy and may even be wrong in a few places).

Here is another drawing that I found on a Russian website. It's tidier than mine, and possibly more relevant as it shows a 72MHz version.

[icedog]

thank you ,Bruce.

[n0kjf]

I have a 9C on 50 MHz and I have access to a Spectrum Analyzer. My 9c is transmitting on 50.86 and it should be on 50.88. Can someone tell me which pot(s) in the RF module to tweak to bring it in line?

Thanks
Lew H.

[lazy-b]

nOKJF, I guess there is nothing wrong with your RF Modules......your transmitter is operating at 50.880 MHZ, but your Spectrum Analyzer is reading at 50.86, I guess the 20 Khz offset is due to the PPM modulation....you have to remove the modulation in order to get an accurate operating frequency....its a complicated task of tuning the Transmitter modules.

its not just simple removing the PPM modulation signal, you have to inject a proper modulating signal.

I guess, the absolute accuracy is not important here, its the Matching or Tuning of your receiver to its Matching Transmitter Modules.

If anybody know the procedure, about tuning the transmitter modules, It would be very interesting leard.

[icedog]

I don't think so, remote control is narrow band, it only has no more than 10k bandwith, it should within 50.880M + 3k and 50.880 - 3k.

Isn't it ?

[Man]

I have a FP-7UAPS transmitter. Recently, I had turn on the transmitter and found out there was not RF output. I immediately put another RF module for test. It is still not RF output. After reading Bruce Abbott’s full schematic of Futaba RF module, I tested transmitter pin 2 and pin 4; it is found that the pin 2 does not have any DC supply. I prepare to send the transmitter to Futaba for repair but they have already stopped to repair FP-7UAPS in 2003.
Can anyone help ?

[lazy-b]

Icedog, Yes, your right a 20 Khz difference is too large....any way my point is you can not just measure the output frequency with ppm signal modulating the carrier......the ppm signal has to be converted to steady constant DC voltages.......or a ppm can be replace by a 50% duty-cycle square wave, and using Spectrum Analyser to adjust for minimum side band splatter.

I guess a frequency counter would be a better equipment to check the Transmitter output frequency......by just putting the Futaba Transmitter near the Frequency Counter, you can monitor the actual frequency output, this will only work on PPM/FM only. my Frequency Counter can not lock on frequecy using PCM mode, I think due to PCM signal, that produce a random like signal that make difficult for frequency counter detect.

MAN, your problem might be due to PCB break in the terminal post that connect the Transmitter Modules and the Transmitter.

due to frequent INSERT and REMOVE of Transmitter Modules, the TERMINAL POST tends to create a hairline Break......lots of FUTABA 7UHP or FF7 owner experience this problem and cause Crashes. I use to have the 7UHP transmitter also, I have added an additional Stranded wire, by directly soldeing the wire from the Terminal post to the circuit.

all 7UHP and FF7 transmitter use a SINGLE SIDED PCB, this can cause a Hairline Crack on PCB.....its nice to know the FUTABA have already improve on the 9CHP transmitter, they use DOUBLE SIDE PCB, to avoid this problem any more.

[n0kjf]

To 20 KHz difference first showed up during a range test with a new receiver, we only got about 65 feet. After that we looked at the Spectrum Analyzer and saw it was calling the center 50.860 MHz. Anyway, I hate to just play around with unknown pots just to see what it does without knowing the potential side effects. We checked on PPM and PCM and it centers on 50.860 MHz on both. With the poor result on the range check, 20 KHz clearly makes a difference.

Thanks for the thoughts,

Lew H

[Bruce Abbott]

20KHz isn't just a bit off, it's on another channel! Your receiver should not be responding at all. Before trying to retune, I suggest verifying the TX crystal's frequency. If the paper label is correct, peel it off and check that it matches the frequency marked on the can :eek:.

If the crystal is OK and the frequency really is 20KHz off, there is probably a fault in the modulator circuit which should be fixed rather than masked by retuning (assuming it is even possible to adjust out that much error). Bearing that in mind, here is the tuning procedure...

The modulator has two trimpots for adjusting the high and low frequencies, typically + and - 1.5~1.8KHz from the channel center frequency. Note that so-called 'FM' R/C transmitters actually use FSK (Frequency Shift Keying), therefore there is no adjustment for center frequency.

You need to disable the normal PPM/PCM input and apply fixed high and low signals. It may be possible to do this through the trainer port. When the PPM input is high, one pot will be more sensitive than the other. Trim the sensitive pot for the high frequency (eg. 50.8818MHz), then set the PPM input low and trim the other pot for the low frequency (eg. 50.8782MHz). Repeat until both high and low frequencies are correct. Your frequency measuring device should be accurate to +-100Hz or better.

[Man]

lazy-b, I have tested PCB side of the RED pin and BLACK pin next to the TERMINAL POST and also does not have any DC supply. The problem still cannot be solved.

Thanks for your advice.

[SlopeKing]

Check wires to the module board... all the way back to the regulator

[Man]

I have also tested the main PCB which the red wire and black wire lead to the RC Module Terminal board, still cannot get the reading of DC.

[SlopeKing]

Sorry to be a pain, but is your radio on? if nothing comes to light, check you're testing the correct wires on the board, and if you are, send it in for service

[SlopeKing]

Right... on module issues, need your help here bruce...

My FP-TP-40, once it 'warms up' or in this case 'heats up', seems to lose range... I fear the RF transistor might be gone or going, but dont know what it is to replace it...

Any ideas??

[Bruce Abbott]

The RF output transistor is a Sanyo 2SC4272. Unfortunately I can't find any suppliers and don't know of any equivalents :(.

[Daniel7866]

My 35MHz module has a (2S)C2314 as power RF. Equivalent BD139, BD230 from TVT ECA table.

Daniel

[dj2u]

@man

I had the same problem with my Robbe/Futaba F-14 (well was the PPM-encoder not RF) but the problem was a dead RF-choke (the blue non SMD things with red and black dots, that pretend to be tantalum caps ;-) they should be conducting if not try to short its terminals (TEMPORARYLI only not as a longtime workaround!) and see if RF works. BTW the dots are the type marks.

hope this helps

diego

[pbunn]

Does pin 3 pull to ground if RF is detected or to half of 9.6 - is the schematic correct - if so the output pin only goes halfway to ground.

[Nicetie]

There are no pots that alter frequency of the transmitter. It is crystal
controlled directly or indirectly via Phase Lock Loop depending on
whether the radio is synthesized or not. You can "pull"
the crystal slightly by increasing or reducing capacitance across it.

Measure the freq by removing the modulation and looking at the output
with a frequency counter. A spectrum analyzer is not accurate for
frequency measurements. Any two way radio shop will have an accurate
counter and can measure for you without even having to connect to the
radio.

[vintage1]

There are no pots that alter frequency of the transmitter. It is crystal
controlled directly or indirectly via Phase Lock Loop depending on
whether the radio is synthesized or not. You can "pull"
the crystal slightly by increasing or reducing capacitance across it.

Measure the freq by removing the modulation and looking at the output
with a frequency counter. A spectrum analyzer is not accurate for
frequency measurements. Any two way radio shop will have an accurate
counter and can measure for you without even having to connect to the
radio.

Well two pots that WILL: adjust the frequency are shown on the schematic, but 20Khz is probably beyind the capability of them to adjust.
I'd expect them to tune a couple of KHz as you indicate.

[flatfour]

MAN: I have attached a pic of a Futaba 9C. Follow the positive voltage pin back to the chokes. In this pic those are the blue components. One of thoise may have gone open circuit.

[iter]

This is an old thread, but I hope you'll bear with me.

Is my understanding correct that there are no RF components in the transmitter? If I took the PPM output of a buddy box and fed it to pin 1, and connected an antenna to pin 5, would it work?

Ari.

[Daniel7866]

This is an old thread, but I hope you'll bear with me.

Is my understanding correct that there are no RF components in the transmitter? If I took the PPM output of a buddy box and fed it to pin 1, and connected an antenna to pin 5, would it work?

Ari.

Do you mean using a buddy box with a Futaba Tx module to make a hybrid?

Daniel

[iter]

Actually, I want to generate my own PPM from a PC soundcard - I've had unexpected success with that idea here, and I've had the idea for some time. My 72MHz TX died, and I'm debating what to buy as a replacement. If this idea works, maybe I can just get a Futaba synthesized RF module and do the rest in software :=)

Ari.

[Daniel7866]

Here is how the PPM signal looks like on my FF9.
Pic is from pin 1 of FP-TP-FM HF module, crystal removed to avoid hf blurring.
Make a similar frame by software and it should work.

Daniel

[iter]

Daniel,

Thanks for the photo and the encouragement. I understand that pin 1 is PPM in, and this is what the scope shows. The photo indicates 2.15v - am I correct in my understanding that the PPM signal varies between 0 and +2.15v?

Also, what I was trying to figure out was if pin 5 ties directly to the antenna, or if there are extra components inside the TX box that the signal passes through.

Ari.

[Daniel7866]

Ari,

You are correct about PPM voltage.
I don't know why the signal is like a staircase. Maybe to reduce harmonic contents.
The 110cm aerial is not directly linked to pin5. See pic.

Let us know your working progress.

Daniel

[dalbert02]

I have the same Rf module (FP-TP-FM 50.860Mhz) and was curious if anyone has replaced the Rf transistor C2314 themselves. I accidently left the smiley antenna off and now my range range test is not passing. I think I may have blown or partially destroyed it (if that is possible). Is there a easy way to measure Rf output? I'd be curious to know if I am anywhere near the legal limit of 750mW.
Thanks,
-dave

Edit: would it be possible to trim a pot to get the full 750mW? I have heard that some of these modules are only putting out 100-200mW or so.

Edit 2: maybe change c2314 for Phillips BLY88C? Or maybe some of these other transistors? http://members.tripod.com/Malzev/comp/power.htm

[Daniel7866]

FYI I tested mine on 35MHz by exchanging the plug W204 (see above) for a 75 Ohm resistor. A good o'scope across the resistor gived me 14 volt peak to peak (@10 V battery) and therefore 333mW RMS. This is NOT input power nor radiated. To check input power times I by V for the final transistor.

Hope it helps.

Daniel

[dalbert02]

Anyone ever heard that a TK module puts out more Rf then a TP module?
-dave

[JimCob]

A while back I converted my Hitec Flash 5 over to the Ham Band using a Futaba TP module and as part of that process I also touched up the module output and matched it to the antenna.

Here's the process I used to tune and match the module to the antenna:

The stock TX antenna on a Flash 5 is somewhere short of a 1/4 wave on 6m, so it exhibits capacitive reactance which I was able to measure using my MFJ-259B. I added an appropriate small inductor between the module and the base of the antenna in order to cancel out the reactance and make the system purely resistive. I assume Futaba designed the module for a 50 ohm output impedance but it really doesn't matter all that much as long as you're in the ballpark. (In my case I think it was 36 ohms which is fine).
The next step was to tune the module using the 2 adjustable inductors closest to the antenna output using a field strength meter for maximum output.
You can also adjust the two trim pots in order to set the high and low modulation frequencies if you have the equipment for it and after doing all this a spectrum analyzer will show you if anything bad is happening with the harmonics or spurs (which of course you want to avoid!)

If you're only interested in measuring the output, then tack on a 50 ohm resistor between the RF output and ground (disconnect the antenna lead) and then use an RF probe + DMM or a high frequency oscilloscope to give you the voltage across that resistor.
For my project I wasn't all that concerned about measuring the output, I only compared it roughly to another TX that I have to ensure that the field strength was about the same.

-Jim

[dalbert02]

Thanks Jim,
Very informative! I was looking for a power/swr meter but most state they need at learst 5w minimum. Glad to hear the MFJ works at our lower powers, plus it does so much more.
-dave

[iter]

I ended up buying a Hitec Eclips 7 with a synthesized module. Am I correct assuming that it's interchangeable with the Futaba unit and has the same pinouts and voltage levels?

Ari.

[dalbert02]

The HiTec module will fit and work in a Futaba radio. However, it is illegal if you are governed by FCC rules. I am not sure if the voltages are "exacty" the same, I just know that it works.
-dave

[iter]

Thanks. Since I'm trying to generate my own PPM and plan to use the module without either a Futaba or a Hitec radio, I won't be using the module in a radio it wasn't certified with :=) Thanks for the warning though.

Mostly, I wanted to confirm that the discussion in this thread applies to my Spectra module.

Ari.

[Gary Warner]

Right... on module issues, need your help here bruce...

My FP-TP-40, once it 'warms up' or in this case 'heats up', seems to lose range... I fear the RF transistor might be gone or going, but dont know what it is to replace it...

Any ideas??

It's unlikely the transistor is bad. If it's running, it's ok. Heat (excessive) can be from a high SWR. Are you using a non-factory antenna? My Airtronics Vision uses a 'rubber duck' antenna and this causes the transmitter module to run warmer.

Sorry to troll, but you post sounded familiar to me.

Gary
--

[Pyrafoh]

Hi Bruce,

I am Peter from Germany an I have a question to the problem of no power output of the RF modul of my Futaba FC28. Because I am also a technician, I measured the + voltage coming in at pin 2 of the modul as described. But there I can measure only about 5,6 V. I think this is to low.
Also without the modul pluged in there is no more voltage.
My question is: Do you have some more schematic diagram of the FC28, so that I can see what is the way of the voltage from the accu...via switch up to the pin 2 of the modul plug.

Thanks in advance for your cooperation and best regards

Peter

[ATMEGA]

have a question.... if i make a coder with some microcontroller and if i can have a good signal,.... can i put it in a module so i can make my own transmitter???

Please Help Me with This...

Daniel

[RX5]

My 35MHz module has a (2S)C2314 as power RF. Equivalent BD139, BD230 from TVT ECA table.

Daniel

I got BD139 tr.. is that tr RF type??

[Daniel7866]

I got BD139 tr.. is that tr RF type??

Not designed for but with a ft at 190MHz there sould be no pb to use it at 35MHz.
Look at their respective datasheets and take your decision.
http://www.datasheet4u.com .

Daniel

[dalbert02]

So I have a module that is giving me trouble so I thought I would take a look. What is the worst I can do? It was glitching anyways. If I break it, I'll toss it in the trash.

WARNING: I am no electronics expert or pretend to be, I just tinker around. Any advice or suggestions is wholeheartedly accepted and encouraged.

I found with my frequency counter that I was off by quite a few Khz from where I should be. I adjusted it to 50.860 where is should be. However, from what I understand, when I apply voltage to ppm in, (+3.3v) the frequency should shift pos by 5Khz. This is a 50 Mhz ham band Futaba Tx module. In the ham band I thought all TXs shift positive. Mine shifts negative by 3Khz when +3.3v is applied , so maybe I am mistaken? I noticed that pots 6 and 7 both adjust the frequency either with or without the +3.3v applied. Pots 1 and 2 both seem to adjust amplitude to a certain point. If I go too high, the nice sine wave on the o'scope gets real dirty. I guess I am overdriving the transistor at some point.

Any of you gurus like to 'elmer' me to get this thing working better?

Thanks,

-dave

PS Also noticed that if I step up the voltage the amplitude increases. If I go above 12v tho, it gets real dirty. The rf out is connected to a 50 ohm dummy load.

edited to correct picture of pinouts

[bitmaniac]

dalbert02:
in this link
http://www.rcgroups.com/forums/attachment.php?attachmentid=1510520
you give the pinout of the module...!
This is different from the pinout of the 1st post!
please confirm which one is the right one as I am going to feed my Sanwa RD6000 with a futaba FP-TP module to revive it!!! (dead smd + dead output transistor on sanwa's rf pcb)
(just for experiments as for FCC rules I live in Europe)
Daniel7866 noted that the signal to ppm in is 0 to 2.15V is it ok?
also do I have to feed the antenna trough the capacitor and rf choke as noted in a previous post?
Well... I 'll give it a try and let you know...
I am searching for a good source of PPM on my Sanwa pcb.... now....

PS: ....also trying to trace pcb tracks of futaba FP-TP-FM module to find out which signal goes where.......

[dalbert02]

Hi Bitmaniac,
OOPS, I think I may have labeled them incorrect. The module in the first post is looking at the back of the module as it sits in your radio TX and my post above is looking at the front of the module. I flipped it over to better connect it to the test circuits.

-dave

PS I fixed the picture in the above post

[village_idiot]

1 2 3 4 5
. . . . .

looking at the back of the transmitter, antenna pointing away from you, flip for looking at the module

left side
#1 PPM
#2 switched battery positive
#3 RF good (pulled low through a transister when signal is present at the final amp)
#4 ground
#5 RF out
right side

tieing pin 3 to ground through a 100 ohm resistor seems to be fine for the Futaba radios

Also the module PPM pin has a voltage on it since the radio is just pulling the line low to make the pulses. The stock Futaba FM modules have about 2.5 volts for this supply. Does the Sanwa provide a real signal for PPM or does it pull the pin low for a signal? If it provieds a real signal, you may need to uncouple the pull up inside the RF module (if you can find it).

[bitmaniac]

:D SUCCESS!

I used FP-TP-FM 35Mhz Futaba module with a friend's sanwa RD6000(with burned rf stage) and EVERYTHING WORKED FINE!

SO now I have a SANWA RD6000 TX with Futaba module!.( :p )....
I am going to do a range check theese days to see how eveything works in the field.
So for SO Good!
(I have not used the capacitor and rf chock at the rf output (pin5) of the module yet... does any one know the value of the L is it 4.7μΗ??)

Also the reliability of the project MUST be tested too!

[arocholl]

Hi there, anyone knows the pinout of the new Futaba transmitter modules, such as the one on 14MZ? It has two connectors, apparently one is for programming the module frequency+region, and perhaps the other is equivalent to the old one (except ppm can be pcm if programmed as such).

Any help really appreciated, I want to reuse a 14MZ module for a DIY project.

TIA

[fwolf15]

Hi there, anyone knows the pinout of the new Futaba transmitter modules, such as the one on 14MZ? It has two connectors, apparently one is for programming the module frequency+region, and perhaps the other is equivalent to the old one (except ppm can be pcm if programmed as such).

Any help really appreciated, I want to reuse a 14MZ module for a DIY project.

TIA

Hello,

is there meanwhile any info about the pinout for the two connectors available?

I 've got a spektrum module with the same two connectors, now I should know where the modul receives the power or on the other hand on which pin from the futaba the + is available.

Wolfgang

[atilla100]

I have the same Rf module (FP-TP-FM 50.860Mhz) and was curious if anyone has replaced the Rf transistor C2314 themselves. I accidently left the smiley antenna off and now my range range test is not passing. I think I may have blown or partially destroyed it (if that is possible). Is there a easy way to measure Rf output? I'd be curious to know if I am anywhere near the legal limit of 750mW.
Thanks,
-dave

Edit: would it be possible to trim a pot to get the full 750mW? I have heard that some of these modules are only putting out 100-200mW or so.

Edit 2: maybe change c2314 for Phillips BLY88C? Or maybe some of these other transistors? http://members.tripod.com/Malzev/comp/power.htm

although abit old topic i want to add my experience,my tx range dropped to nearly 1/20 of the original range and i found out that changing the main output transistor(2sc2314) completely solved the problem(it was interesting that the old transistor passed the ohmmeter test)

[lslewis]

Converted my 9C to Spektrum and forgot how many planes I have on 72Mhz. So I purchased a used 7C, plugged in a new tx crystal for channel 48 and no joy. The schematic I found on this thread indicated it is a 14mhz crystal working on it's 5th overtone. I am guessing you tweak L1 (red arrow) and watch for a peak or minimum current/volts across the emitter resistor. Any help or clue will be appreciated

I have a friend who can get me exactly on frequency so as to keep the FCC happy;)

Hurricane Larry