jbrundt

My Feedback: (2)

I am an exclusive Futaba or Hitec user and I'm not familiar with JR's buddy boxes or trainer cords. Could someone please explain them to me.

I was asked to help a co-worker learn to fly. They have an old JR Max 4. The Tx has a trainer jack on the back that looks like it takes a mini-phono plug. The instructions for the radio say to use a JRATC001 trainer cord. Do they still even make these? I was at Horizon's web site to check out the trainer cords but of course they have no picture nor do they list a buddy box for JR radios (and they are the US distributor....go figure)

Any help is appreciated.

TIA,

Jeff

visioneer_one

My Feedback: (506)

The JRATC001 trainer cord is really just a cord with mono mini phone plugs on both ends. Pick one up at your local Radio Shack for $5 bucks or so.

NOTE: be sure to get a MONO cord, not a STEREO one. Check the package description carefully!

Pretty much any JR radio can be used as a buddy box. The slave radio is powered by the master; you don't need to have a crystal (or battery) installed. Check the for-sale listings - people are always selling off their old 4/5 channel transmitters for cheap. Alternately, your buddy could upgrade his radio and use the old Max4 as a buddy box.

heliguy

My Feedback: (3)

Jeff, You are correct that JR uses a mono mini phono plug for its buddy box connection. Unlike Futaba (and Hi-Tec) the JR setup requires that the slave have a battery, but the slave transmitter is not turned on. When the phono-plug is plugged into the transmitter, it turns on the encoder section of the transmitter but not the RF. (To test this just plug any mini-phono plug into your JR transmitter and the unit will come on but will not be transmitting.)

The trainer cord is two mini-phono plugs wired tip-to-tip and sleve-to-sleve. You can use any high quality patch cord .

All this said, you cannot connect a JR to a Futaba or Hi-Tec. Even if you construct a usable patch cord they will not work. This is because of the way JR and Futaba have chosen to sequence their servo pulses. Futaba’s sequence sends Ail, Elev, Thr, Rud while JR’s sequence sends Thr, Ail, Elev, Rud. What this means is that if you transferred control to the slave JR from a Futaba the throttle would work the aileron, the aileron would work the elevator, and the elevator would work the throttle.

For what it’s worth—Al
Http://www.rchelibase.com

Steve Lewin

Unless you construct this design of Ken Hewitt's http://www.welwyn.demon.co.uk/lead/lead.htm

Probably not worth the effort but Ken can't resist a challenge like "You can't connect JR and Futaba".

Steve