FG4 AM convertable to 2.4ghz?

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FG4 AM convertable to 2.4ghz?

Postby quarry44 » Fri Aug 19, 2011 7:51 am

I have inherited an old but nice Futaba FG4(the gold metal case job) on 72.350 AM,for which I have no receiver.
Is this a candidate for conversion to 2.4 with a hack module,or won't it work with an AM radio?
I'm loath to throw this tx out,as it belonged to a good friend of mine,who has passed away.
Thanks .Hans.
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Re: FG4 AM convertable to 2.4ghz?

Postby bmsweb » Fri Aug 19, 2011 11:47 am

I have one of those oldies but its an FM one :) I have no idea myself
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Re: FG4 AM convertable to 2.4ghz?

Postby ergocentric » Fri Aug 19, 2011 1:45 pm

1. if it has a trainer port chances are good
2. if it has a transmit module chances are good
3. if you have electronics experience chances are good

that being said I think I have an FG3 in the garage somewhere, my first radio, very long antenna
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Re: FG4 AM convertable to 2.4ghz?

Postby quarry44 » Fri Aug 19, 2011 9:29 pm

1.It does have a trainer port
2.It does have a module
3.My electronics experience relates to building a few small kits,like crystal checker,speed control,etc.
My main concern was the fact it's an AM tx,I thought it had to be FM to be able to be converted to 2.4.
I have no rx for this,and can't buy one,so it's pretty much useless as it is.Hence my question.
Thank,ergocentric,for answering both my questions,it's much appreciated.
Hans.
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Re: FG4 AM convertable to 2.4ghz?

Postby ergocentric » Sat Aug 20, 2011 3:20 am

simple if you have a trainer port,

http://users.belgacom.net/TX2TX/tx2tx/e ... 2txgb3.htm

you will need three connections
+V (battery positive)
gnd (battery negative)
and the signal out pin

depending on the 2.4 conversion you may want a BEC to power it
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Re: FG4 AM convertable to 2.4ghz?

Postby quarry44 » Thu Aug 25, 2011 8:23 am

I've done some investigation,and found the trainer port less than useful.I could only find one pin that had a voltage on it.Perhaps the fact that the switch is spring loaded to the "off"position has some bearing on this.
So I looked at the module connections instead.It appears they don't conform to the pinout shown online in various places.Looking at the back of the tx with the module removed,I got the following:
Left to right,pin1=no volts.pin2=neg ground.pin3(centre)=4.8volts.pin 4=12.6 volts.pin5=neg ground.This transmitter uses a 9 cell battery pack,hence the voltage.
Am I correct in assuming the 4.8 volts is the PPM connection?
I've asked the fellow supplying the module,and he's doing some investigating of his own,but I thought I'd ask too.
There's a photo of the back of a Futaba module on the rcmf forum,and that shows the ppm on pin5,batt+ on pin4,pin3 blank.batt- on pin2,and pin1 blank.
Hence my doubts.Was this series of transmitters such an oddball?There's very little online about them.72 mhz was not a recognized frequency in NZ when this tx was made,so I'm assuming it was imported from elsewhere at some stage.
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Re: FG4 AM convertable to 2.4ghz?

Postby ergocentric » Thu Aug 25, 2011 12:43 pm

quarry44 wrote:I've done some investigation,and found the trainer port less than useful.I could only find one pin that had a voltage on it.Perhaps the fact that the switch is spring loaded to the "off"position has some bearing on this.
So I looked at the module connections instead.It appears they don't conform to the pinout shown online in various places.Looking at the back of the tx with the module removed,I got the following:
Left to right,pin1=no volts.pin2=neg ground.pin3(centre)=4.8volts.pin 4=12.6 volts.pin5=neg ground.This transmitter uses a 9 cell battery pack,hence the voltage.
Am I correct in assuming the 4.8 volts is the PPM connection?
I've asked the fellow supplying the module,and he's doing some investigating of his own,but I thought I'd ask too.
There's a photo of the back of a Futaba module on the rcmf forum,and that shows the ppm on pin5,batt+ on pin4,pin3 blank.batt- on pin2,and pin1 blank.
Hence my doubts.Was this series of transmitters such an oddball?There's very little online about them.72 mhz was not a recognized frequency in NZ when this tx was made,so I'm assuming it was imported from elsewhere at some stage.


does the transmitter contain a CD8081 or NE5044 encoder chip? you can pull PPM from pin 11 iirc

blog.quantifly.com: (since removed)
Compared to 2PL Attack 4 use single board for both signal and modulation therefore
to trace its ppm signal source it has to focus on its signaling ic - CD8081N or
NEE5044 Programmable seven-channel RC encoder, according to the datasheet the
ppm signal is located on pin 11, where voltage and ground is 16 and 8 respectivity.


hrrrm, no PDF attachments, plus it was huge, so I took a snapshot of the datasheet
Attachments
NE5044.jpeg
Signetics NE5044 seven channel radio control encoder chip
NE5044.jpeg (100.2 KiB) Viewed 3769 times
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Re: FG4 AM convertable to 2.4ghz?

Postby ergocentric » Thu Aug 25, 2011 1:01 pm

As an aside I wanted to add that 72MHz is/was big in north amerika, long before FM or PCM radios became available, wide band (80kHz) AM radios were used all over, as the 27MHz band was shared with ground vehicles and is just above CB radio frequencies (ground vehicles went to 75MHz) (27MHz is still allowed, wide band 72MHz is not)

So, there should be plenty of these transmitters in basements around here (Canadar)

The conversions are cool, but what you loose is channel mixing, programmable stuff like dual rates, improved latency, and the possibility of synchronizing channels (collective pitch comes to mind)
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Re: FG4 AM convertable to 2.4ghz?

Postby Ugly » Fri Aug 26, 2011 3:19 am

The Frsky DYI doesn't use the transmitter section of you radio, the 2.4 gig and mixing is generated in the Frsky module, all you need to do is feed the PPM modulation into the DYI module and it will work, remove the xtal from the old tx area to kill it or if you can remove it if it is on a separate board or module. whilst you only need 4 channel receiver I would go for the 8ch Frsky receiver as it gives far better range, see my post re Kraft 7C conversion in the DYI sect, I have been using the Kraft for 10 months with out a glitch, though you are only starting with a futtabaa so one may not be able to expect to much Hi Hi !!!

all the best with it Ugly
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Re: FG4 AM convertable to 2.4ghz?

Postby quarry44 » Sat Aug 27, 2011 5:05 am

I had another look at this today,and found that the module needs to be plugged in to register any voltages on the trainer socket.
However,I have found a piece of cabling with a connector that's a nice fit on the module pins.So I can either use those pins,or the trainer socket to connect my module.
I'm still waiting for my Frsky module to be delivered.I'll post an update when I get going on the conversion.
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