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Buddy Box options

baslug

Junior Member
#1
sorry if this is a tired subject, but I'm still fairly new to the hobby and trying to make sure I'm wrapping my head around the options correctly.

So, I'm currently flying with a 72Mhz Futaba T6exhp I bought ~10 years ago. I've installed the FrSky DIY 2.4Ghz module to give it a little expanded functionality - mainly so I don't have to change out the 72Mhz Rx everytime I want to change planes. I installed it with a DPDT switch to retain the ability to use 72Mhz and it's really easy to switch back and forth.

I'd like to teach my son & brother-in-law to fly, so I'm looking for a way to set up a buddy-box system. I also know that I'm quickly outgrowing the Futaba radio since it only has a 6 model memory and these FT planes are so easy to build that my fleet is expanding rather quickly. So far, from reading these forums, Taranis appears to be hands-down the most bang for the buck.

So, here are the options I perceive:
- HK has a $16 dual Rx controller board (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=70604) which looks like it would allow me to still use the Futaba radio... I'd just need another radio and then stuff an extra Rx into whatever plane we're flying. On the super cheap side, I could get the <$30 HK 6ch, Turnigy 6x, etc. Or if I wanted something my son could grow into, pick up a used Spektrum Dx6... or better yet, upgrade my own radio with a Taranis and hand him the Futaba. I was thinking the Spektrum would also open up the list of BNF planes that we could play with too.

My other options would be to buy two new radios that can buddy with each other without the need for two Rx's in the plane:
- 2 x Spektrum Dx5e (will these buddy with each other?) ~$120
- Spektrum Dx6i + Spektrum Dx5e ~$220

It seems to me that instead of spending close to $200 on two cheap Tx's which aren't much better than my current Futaba, it'd be better to get myself into a Taranis and find a second cheap Tx that it can bind to.

Right now, I'm leaning on the semi-cheap side with the dual-Rx board and a used Spektrum. Then I can always upgrade to a Taranis later.

I know there are lots of other permutations on the same stuff.
I just wanted to see if anyone had some advice... or if there was something I'm not considering.
 

HawkMan

Senior Member
#2
I'm not sure about your 72Mhz, but you don't really need special radios to just link them with a trainer cable. At least all radio's with a jack t least usually talks pretty well with each other.

I connected both a Hitech Optic 6 sport and a cheap 6 channel non programmable HK tx to my Taranis and both worked great. I believe you're pretty much limited to 6 channels from the trainer radio over the trainer (PPM) cable though. But those who need a buddy box training shouldn't need anymore if that much anyway, 4 should be what they practice on.
 

baslug

Junior Member
#3
my understanding was that in order to buddy box, the Tx's needed to be the same brand in order to talk with each other.

The controller board I linked to gets around this by actually using two separate Rx's on the plane. and the Taranis gets around it simply b/c it's open-source, and well, people get to write their own way around it... though i'm sure some of the bigger brands keep their code closed and make it harder to do.

if i'm absolutely wrong on this, I'd be just as happy to buy a cheap Tx + appropriate cable.
 

HawkMan

Senior Member
#4
Not really, I'm not sure about all Tx's and what they use to speak, but I suspect it's mostly PPM. either way as I said, the Taranis at least can be master for at at least HiTec as well as most cheaper off brand or china brand Tx's.

The controller board you put in the plane with input for two Rx's isn't to avoid this(though it can avoid it with certain brand that use special trainer plugs and protocols) but for Wireless buddy boxing across brands. for wireless buddy boxing all the brands use their own systems. Heck as far as I know only Spektrum even provides wireless buddy boxing.

Futaba I believe uses a special trainer cable(square ish DIN like plug with several pins) if I'm not mistaken and may not be able to talk to other Tx's though a standard trainer cable though. On the other hand most USB sim dongle's come with adapters that just turn these special plugs into regular 2 wire jack plugs, so I don't know, guess you'll just have to order a cheap 6ch HK to try. and if it doesn't work you just order a Taranis to replace your old 72Mhz Futaba, and it'll talk to the cheap HK transmitter over a standard jack to jack stereo(well mono but it doesn't matter) cable just fine.
 

HawkMan

Senior Member
#5
Yeah, the Futaba has the weird square ish din like plug for the trainer cable. more curiously, according to the manual. this specific transmitter can ONLY be used as a student radio not as the master.

So you'll need to buy a new transmitter to use anyway. in which case you have a few options.

Buy two cheap HK radio's and use a normal jack to jack mono/stereo cable.
But since you're used to a simple computer radio that has expo and dual rates and such that would be a bit of a downgrade. so another option
Buy a Taranis for your main radio, upgrade your radio and
- buy a cheap HK 4-6 channel for the student
- buy a Spektrum DXe or DX4-6 for the student radio, also let's you play around with BNF planes without getting a module for the Taranis.
- buy any other radio to your liking with a ppm compatible jack out for the student.

OR get the HK "wireless buddy box" module. and a cheap TX and receiver. use your existing radio for the master input and a cheap 2.4 HK radio for the student input. the benefit is that it is wireless of course, but it ads weight and complexity and stuff that can go wrong. and you need two receiver in the plane. it's a bit of a spaghetti.

OR Spend a lot of money to buy a DX9 and a DX6 for actual wireless buddy boxing (the radio's talk to each other wirelessly. the master talks to the plane)



There is another option. but it requires some googling to find out how to do it and probably some good soldering skills. The new Taranis firmware allows you to connect a receiver with PPM output either itnernally in the radio or int he module bay, or a S.Bus receiver you can put in the battery bay and connect to a serial port there. This allows the Taranis to act as the master on a true wireless buddy box. With S.Bus a futaba receiver should work, with ppm, most brands make ppm receivers you can use, from cheap flysky to spektrum(I think).
 

baslug

Junior Member
#6
Thanks for the input, HawkMan. I didn't realize the Futaba Tx could only be used as a student radio and not master.

Looks like I'll go ahead and take the plunge and buy a Taranis as my main and then find a second-hand Spektrum for student/BNF planes.
 

HawkMan

Senior Member
#7
I have not personally tested that spektrum radios send a default ppm signal the taranis can decode on the trainer port, so I can't personally guarantee spektrum's will work.

But they use a standard jack port so I would assume so, but assumption is the mother of ... and so on, but I'm sure there are other people here that should be able to give a definite answer.
 

HawkMan

Senior Member
#8
Well according to google and RCGroups, Spektrum radio's should work fine as student radio's with the Taranis as master. the one issue is that some may need a spektrum trainer cable and not just a regular stereo cable for some reason. but I believe that's just a mono to mono jack cable anyways. not sure why a stereo wouldn't work as they're essentially the same but it happens on some gear.

Either way, it should work fine.
 

HawkMan

Senior Member
#11
The link has good is slightly outdated in some situations info. For the Taranis I'm not sure it actually care if the ppm signal is positive or negatively modulated.
 

baslug

Junior Member
#12
Just to update...

I took the Taranis/cheap-HK radio route to start with. i figured it'll get us flying, i get an excuse to selfishly upgrade my radio, and if the kiddo/B-I-L decide to stick with it, they can take over the old Futaba or invest in something else later. If we get into playing with the BNF's, it looks like Taranis has an external module that'll connect it... and it doesn't hurt to have an extra cheap radio/receiver to knock around with.

to my dismay, the HK-T6A i bought didn't have a 1/8" jack for the trainer port... instead, it was a 4-pin mini-DIN jack. I found a 4-yr-old thread on rcgroups with a circuit diagram of the HK-T6A (http://www.rcgroups.com/forums/showthread.php?t=1516704) and was able to wire together an old S-video and 1/8" mono cable i found around the house. so far, it works swimmingly on the bench. hoping to try it out in the air this evening.

i feel like i should be earning a B.S. in Taranis programming with all the research i've had to do to program my models in the transmitter... but i'm figuring it out ok. i forgot that open-source isn't always user-friendly. need to establish some best practices to make sure everything is consistent.

thanks again for y'alls help
~Ben
 

HawkMan

Senior Member
#13
Yeah, you'll always learn when using the taranis, a lot of stuff you do at first you'll later find out, you could probably do a lot simpler as they have built in functions for just that. it's just put in places programmers think is logical and not users :)
 

bhursey

The Geeky Pilot
#14
Im in the same boat. I have a futaba t6xa 72mhz i want to teach my dughter how to fly i was actualy pondering getting a second t6xa of ebay to buddy box my wife does not want me to spend allot of $. I wanted to buy 2 tyrningy 9x. But that was a no go.
 

baslug

Junior Member
#15
Im in the same boat. I have a futaba t6xa 72mhz i want to teach my dughter how to fly i was actualy pondering getting a second t6xa of ebay to buddy box my wife does not want me to spend allot of $. I wanted to buy 2 tyrningy 9x. But that was a no go.
looking at the manual for the T6xa (http://manuals.hobbico.com/fut/6xas-hs-manual.pdf) it looks like two t6xa's will buddy together fine.

I can't tell if the t6xa will act as the Instructor to a controller other than another t6xa. i imagine if you can pair two up, it should. if it will, and you have even basic soldering skills, you may be able to wire up a cord and buddy it with a cheap HK transmitter (http://www.hobbyking.com/hobbyking/...2_4Ghz_6Ch_Tx_Rx_V2_Mode_2_AR_Warehouse_.html) I'll look into it more and see what I can find. This would probably be the least expensive option...just a little uncertain if it'll work or not.