Teacher/student - different transmitter brands
TB
Does anyone know if it's possible to connect two different brands
of transmitters to use the teacher/student functionality?
(In this case: JR->Multiplex)
I realize that I would have to make myself a custom cable, but
AFAIK it's only the PPM signal that's interesting and that signal
should be the same on every transmitter. (Please correct me if
I'm wrong on this one).
Looking forward to your comments,
/TB
The Raven
news:1124356216....@g47g2000cwa.googlegroups.com...
Hitec and Futaba will work together but it's recommended by Hitec that you
use their cord. Some of the later Hitec radios can have problems with
certain trainer cords. The rumour (unconfirmed) is that some leads allow
voltage to flow back from the Futaba to the Hitec, often smoking both
radios. Anyone got the hot gossip on this rumour?
--
The Raven
http://www.80scartoons.co.uk/batfinkquote.mp3
** Now I will bring chaos to the world!
Tom Watson
model. The student and the teacher could have different brands of TX and
could even have different modes. Can't remember where I saw it. You had a
switch on the teachers tx that cut off the RF. then the student had control.
When the teacher need to regain control he let go of the switch.
regards
Tom Watson
Sydney Australia
"TB" <tbju...@gmail.com> wrote in message
news:1124356216....@g47g2000cwa.googlegroups.com...
A.T.
"Buddy Boxes. Servo Leads.Simulators.Interface"
e.g.
TX 2 TX *** http://users.belgacom.net/TX2TX/
Buddy Box System Operation - RCFU
and many more at Alan's Hobby, Model & RC Web Links
http://homepages.ihug.co.nz/~atong/
.................................................................
regards
Alan T.
"TB" <tbju...@gmail.com> wrote in message
news:1124356216....@g47g2000cwa.googlegroups.com...
AeroMutt
functions are the same, you can probably do it. BTW, Hangar 9 makes an
interface that allows Futaba and JR stuff to buddy box together.
Morris
John Alt
swils...@yahoo.com.au says...
>
> Hitec and Futaba will work together but it's recommended by Hitec that you
> use their cord. Some of the later Hitec radios can have problems with
> certain trainer cords. The rumour (unconfirmed) is that some leads allow
> voltage to flow back from the Futaba to the Hitec, often smoking both
> radios. Anyone got the hot gossip on this rumour?
>
hitec cord has a diode. Without it, this combo will power the student
radio, allowing it to transmit. You run the risk of shooting someone
down with the student radio. Solutions are to remove the students
crystal or frequency module and/or antenna, or to avoid the situation
and use a Hitec buddy cord.
tx2tx
news:b30b1$4304cbb8$d818625b$73...@NAXS.COM...
---------------------
Hi to all,
That positive shift problem of tue U.S. is of no importance, as this
concerns the RF-part. As the original author of the question suggests, it's
only the ppm-signal one should care about.
If you have just a little proficiency in electronics, or not even
electronics, just electrics and you know which side of a soldering iron is
hot, then you can make a buddy lead that would probably work between JR and
Multiplex. And if it does'n work, it will do no harm. You even can reverse
polarity of the signal, if signal is reversed, it will work. If it finally
does'n work, probably the signal must be a little manipulated with a few
electronic components, but unfortunately, then I cannot help anymore.
Anyway, as Alan Tong's excellent RC-URL-list mentions, refer to my website
for full details : http://users.belgacom.net/TX2TX : buddy box compatibility
problems between different brands of RC-transmitters.
Olivier
--
http://users.belgacom.net/TX2TX : buddy box compatibility problems between
different brands of RC-transmitters.
To answer, remove "nopub" from tx...@belgacomnopub.net
Doug McLaren
tx2tx <tx...@nopubbelgacom.net> wrote:
| That positive shift problem of tue U.S. is of no importance, as this
| concerns the RF-part. As the original author of the question
| suggests, it's only the ppm-signal one should care about.
Yes, but the PPM signal is exactly where the shift _is_.
It would be a simple matter to change the shift from one to another
(needing probably only a single chip) but if your buddy cord doesn't
take that into account, then it's not going to work.
Even the site you mentioned mentions this. Look at this picture --
http://users.belgacom.net/TX2TX/tx2tx/image/fig1-02.gif
this is the PPM signal, not the RF signal, and he talks about positive
and negative shift.
He also says this --
A transmitter with a positive PPM modulation will in theory not be
compatible with a transmitter working with a negative
PPM-modulation. In practice, my FC18V3Plus seems to understand
sometimes an opposite PPM-signal
He then says that `this has nothing to do with the positive and
negative SHIFT system which applies to the United-States and Canada',
which is probably what you're thinking of, but I'm not so sure I
agree.
Either way, he seems to think there is a problem -- and so do I. I'm
not sure I agree with him about the _source_ of the problem, but I'll
admit that he's done a lot more research on it than I have, so he may
very well be correct.
| If you have just a little proficiency in electronics, or not even
| electronics, just electrics and you know which side of a soldering
| iron is hot, then you can make a buddy lead that would probably work
| between JR and Multiplex. And if it does'n work, it will do no harm.
There is potential to do harm. Depending on the transmitter brand,
some master boxes provide power to the slave box. If you get that
power into the wrong pin, you could fry something.
| Anyway, as Alan Tong's excellent RC-URL-list mentions, refer to my
| website for full details : http://users.belgacom.net/TX2TX : buddy
| box compatibility problems between different brands of
| RC-transmitters.
And a fine site it is.
Either way, as long as you're not doing PCM, you can usually work out
buddy box connections between most brands of transmitters now.
--
Doug McLaren, dou...@frenzy.com
"One in a million odds happen eight times a day in New York." -- Penn Jilette
tx2tx
news:uogNe.154931$0f.7...@tornado.texas.rr.com...
Hi again,
As you didn't seem to notice, I am the author of the site
http://users.belgacom.net/TX2TX : buddy box compatibility problems between
different brands of RC-transmitters.
I live in Europe, where that positive and negative shift is non-existent.
Altough this positive and negative shift is nonexistant for the old
continent (all transmitters I had in my hands are exclusively positive
shift), the PPM-signal of some transmitters I had in my hands are positive,
some are negative. This just as proof that the negative and positive shift
is only related on how that PPM signal (be it positive or negative) is send
: either frequency shift below the carrier, either the frequency shift above
the carrier-frequency.
As you say, however, "Either way, as long as you're not doing PCM, you can
usually work out buddy box connections between most brands of transmitters
now."
And you are very correct by saying "Depending on the transmitter brand, some
master boxes provide power to the slave box. If you get that power into the
wrong pin, you could fry something."
That's why I suggest in chapter 2 about making buddy leads the following :
"In any case and as mentioned before, I dissuade everybody to use a lead
that gives battery-power from master to pupil transmitter"
In chapter 6, there's an (incomplete yet) overview of what type of
transmitters have been connected to each other. There have been several
Graupner transmitters as slave connected to a Multiplex transmitter. As
Graupner is rather similar to Jr for some models...
Unfortunately, I have nearly no (or not at) all feedback from the US (where
JR is so popular) about people connecting different brands to each other.
Probably the doom of the FCC has something to do with it.
Olivier
http://users.belgacom.net/TX2TX : buddy box compatibility problems between
different brands of RC-transmitters.
A.T.
Both must be set to PPM if linked together - neither will operate the
other's PCM RX.
There is no diode in the Hitec lead, Pins 4 & 5 are simply soldered together
at the student end only.
Hitec Laser and Eclipse can also buddy mode 1 to mode 2 and vice versa.as if
both are on the same mode.
NB: the new Futaba 9C uses a unique square plug.- reason could be that it is
more compact and the plug and cord are almost flat to the TX case and not so
easily damaged as the round type used on earlier models.
see = http://www.acehobby.co.nz/ossb2/root/OSSBEC1/showitem.asp?PID=53698
Caution # 2:
Some of the very early Futaba 8UAP would let the smoke out of their trainer
board when connected to Hitec slave with TX battery in place. The 10焙 coil
would burn out. Buddy operation would not operate but no other damage to
that 8UAP, remaining functions operating normally - simple fix with no more
problems.
Futaba 9ZHP has 5V + through centre pin which is earthed to plug shield on
Hitec buddy boxes, not a good combination.
It is now possible to connect JR to Hitec or Futaba.
refer to 'Buddy Boxes. Servo Leads.Simulators.Interface"
at Alan's Hobby Web Links http://homepages.ihug.co.nz/~atong/
in particular "Intelligent Buddy Box Lead By Ken Hewitt" and
"TX 2 TX "
regards
Alan T.
Alan's Hobby, Model & RC Links
http://homepages.ihug.co.nz/~atong/
.............................................................
"John Alt" <jaltdoesn...@bellsouth.net> wrote in message
news:MPG.1d6ed7632...@newsgroups.bellsouth.net...
Doug McLaren
tx2tx <tx...@nopubbelgacom.net> wrote:
| > Either way, he seems to think there is a problem -- and so do I. I'm
| > not sure I agree with him about the _source_ of the problem, but I'll
| > admit that he's done a lot more research on it than I have, so he may
| > very well be correct.
...
| As you didn't seem to notice, I am the author of the site
| http://users.belgacom.net/TX2TX ...
Yes, I missed that.
| I live in Europe, where that positive and negative shift is
| non-existent.
Right, but it seems an awfully big coincidence that in the US, the
same brands that have a positive modulated PPM shift also have a
positive RF shift, and the same brands that have a negative modulated
PPM shift also have a negative RF shift.
What seems likely to me is that the PPM shift is the _cause_ of the RF
shift, and outside of the US the manufacturers simply added a bit of
circuitry to reverse the shift before feeding it to the RF stage, or
perhaps the RF stage itself reverses it. (I wish they'd done that
over here, but I guess it saved a bit of money for Futaba and Hitec by
omitting the components.)
This would be a relatively easy thing to verify -- I would take a JR
TX as a buddy box, and connect it to a Futaba TX master (doing no
translation of the PPM signal in the trainer cord), then see which
brand of RX works with it. If a JR RX works (with the Futaba TX, but
the PPM signal coming from JR), then I'm correct. If the Futaba RX
works, then I'll be confused. If neither works, then you'll be right.
Since you're not in the US, you probably don't have any US RC
equipment, so any verification of this will probably have to be done
over here. I'll see about setting up the test if I get a chance.
| Altough this positive and negative shift is nonexistant for the old
| continent (all transmitters I had in my hands are exclusively positive
| shift), the PPM-signal of some transmitters I had in my hands are positive,
| some are negative. This just as proof that the negative and positive shift
| is only related on how that PPM signal (be it positive or negative) is send
| : either frequency shift below the carrier, either the frequency shift above
| the carrier-frequency.
It's not proof, as I've suggested. (And it's not really possible to
prove anything anyways, only disprove. It may suggest this, but I do
have an alternate explanation, one that can be verified (but not
proven, of course.))
| Unfortunately, I have nearly no (or not at) all feedback from the US
| (where JR is so popular) about people connecting different brands to
| each other. Probably the doom of the FCC has something to do with
| it.
I'll bet it's more economics than `FCC doom' -- by not standardizing
the shifts in the US, Futaba and Hitec probably saved $0.15 per
transmitter or so. Also, they may see some value in not being
compatible with JR and Airtronics.
As for JR being so popular over here, it seems to vary a lot. At the
glow club I fly at, Futaba reigns supreme. At the glider club it's
JR. Hitec is a distant third at both, especially with low end
equipment, and Airtronics is very rare. The glider club also have a
few Multiplex users. The glow club has never heard of Multiplex :)
--
Doug McLaren, dou...@frenzy.com
"Nostradamus told me this would happen. Smug bastard."
John Alt
> Hitec and Futaba TX and RX are fully compatible except for PCM systems.
> Both must be set to PPM if linked together - neither will operate the
> other's PCM RX.
> There is no diode in the Hitec lead, Pins 4 & 5 are simply soldered together
> at the student end only.
>
it myself. I'm sure you're right about it. The important issue, though,
is the Futaba/Hitec/Futaba combo. I've got a Futaba 4 channel FM on my
PT 40, with a hitec buddy box and a futaba cord. If I leave the crystal
and antenna on the hitec, it WILL transmit on whatever frequency that
crystal happens to be. This problem is most dangerous on the flightline
when a taxiing model on that frequency gets close to the student box.
A.T.
how to put past posts in more simple English..........
Whenever connecting a buddy box, the module and/or crystal should be removed
from the buddy box - no matter which brand of TX is used. Not only will
this prevent extraneous transmissions, but in buddy boxes which require a
battery to be in place (do not turn on - plug in activates power) as in JR,
and computerised TX.this almost doubles the battery on time as you are not
generating RF.
There is definitely no diode in a Hitec Trainer Cord. Two pins of the Hitec
Trainer lead are shorted together at the student end. This is the same as PC
Simulator leads for Hitec & Futaba 6 pin DIN plugs.
The Hitec Trainer lead is preferred for both use with Futaba TX with a round
6 pin DIN socket and Hitec systems, as it is not only longer and much more
flexible it is usually better priced.
Once more, please refer to
"Buddy Boxes. Servo Leads.Simulators.Interface" at Alan's Hobby, Model & RC
Web Links
http://homepages.ihug.co.nz/~atong/
especially the information on the many different connections between
numerous brands shown at TX 2 TX *** and how to make your own cables.
regards
Alan T.
Alan's Hobby, Model & RC Web Links
http://homepages.ihug.co.nz/~atong/
.................................................................
"John Alt" <jaltdoesn...@bellsouth.net> wrote in message
news:MPG.1d7029c59...@newsgroups.bellsouth.net...
tx2tx
"Doug McLaren" <dou...@frenzy.com> wrote:
> Right, but it seems an awfully big coincidence that in the US, the
> same brands that have a positive modulated PPM shift also have a
> positive RF shift, and the same brands that have a negative modulated
> PPM shift also have a negative RF shift.
>
> What seems likely to me is that the PPM shift is the _cause_ of the RF
> shift, and outside of the US the manufacturers simply added a bit of
> circuitry to reverse the shift before feeding it to the RF stage, or
> perhaps the RF stage itself reverses it. (I wish they'd done that
> over here, but I guess it saved a bit of money for Futaba and Hitec by
> omitting the components.)
>
> This would be a relatively easy thing to verify -- I would take a JR
> TX as a buddy box, and connect it to a Futaba TX master (doing no
> translation of the PPM signal in the trainer cord), then see which
> brand of RX works with it. If a JR RX works (with the Futaba TX, but
> the PPM signal coming from JR), then I'm correct. If the Futaba RX
> works, then I'll be confused. If neither works, then you'll be right.
>
> Since you're not in the US, you probably don't have any US RC
> equipment, so any verification of this will probably have to be done
> over here. I'll see about setting up the test if I get a chance.
Perfect! Please keep in touch if you ever find something that would confirm
you view! As my electronic knowledge is much to restricted and as I never
had any confirmation on the RF-signal having the same sign as the
ppm-signal, I am curious.
>
> | Altough this positive and negative shift is nonexistant for the old
> | continent (all transmitters I had in my hands are exclusively positive
> | shift), the PPM-signal of some transmitters I had in my hands are
positive,
> | some are negative. This just as proof that the negative and positive
shift
> | is only related on how that PPM signal (be it positive or negative) is
send
> | : either frequency shift below the carrier, either the frequency shift
above
> | the carrier-frequency.
>
> It's not proof, as I've suggested. (And it's not really possible to
> prove anything anyways, only disprove. It may suggest this, but I do
> have an alternate explanation, one that can be verified (but not
> proven, of course.))
OK, not a proof indeed.
> Doug McLaren, dou...@frenzy.com
> "Nostradamus told me this would happen. Smug bastard."
Thanks for you critical view on this matter, indeed.
Olivier
--