HobbyKing 4 channel HK-T4A Tx - 2.4 GHz: USER MANUAL
POST #1 INTRODUCTION:
[If you have the 6 channel transmitter, start at posts #154 and 155 to find the better info]
EDIT - July 2013
This radio is now being sold as part of a RTF (Ready To Fly) plane (see message #329)
So this old thread (manual) will probably get much more use now.
It is still a good basic radio and deserves the extended life that this event will cause.
EDIT - Dec 2010 - an updated version of this radio has superseded the old version.
This manual will still be of use for the new version.
The changes are for the better:
1. New frequency hopping technology is used - instead of one channel being used, many channels are used in sequence giving you more immunity to interference.
2. The receiver is all in one small box - no longer in two small boxes.
3. Users report range to be at least as far as the old version.
4. The old and new versions are NOT compatible with each other so you can't interchange receivers.
5. The transmitter case looks the same - just a slight difference in the label (please see messages 192 to 195 and pictures below for the details)
This 4 channel- 2.4 GHz, HobbyKing HK-T4A Transmitter and HK-TR6A Receiver -“manual” (more like a lengthy instruction sheet) may help you if you have purchased the radio or are just considering its purchase.
It is a VERY inexpensive radio and is shipped without a manual, or even a simple instruction sheet.
Here is the site that shows the catalog entry for this radio.
EDIT: This link at HK now points to the NEW, incompatible version.
The thread presented here was started for collecting the information necessary to construct a manual for the 2.4 GHz, HobbyKing HK-T4A Transmitter and HK-TR6A Receiver.
Most of that information has now been collected. So, I will edit it and present it in the first four posts of this thread (original four posts – deleted). I call myself the “editor”, not author, since most of the information was kindly, at my urging, contributed and gathered by others more knowledgeable than I about this radio. You will find the links to other discussions that were not limited to just this radio scattered through this thread – explore them – they are very interesting. Thanks so much to all who contributed. Even though the first four posts have been erased (they were written by me and were, mostly, my plea for information) the other posts remain and may be useful to you.
This manual is for ONLY the 2.4 GH, HobbyKing HK-T4A Transmitter and HK-TR6A Receiver.
There are other, somewhat similar, radios now on the market that have more features and more channels with messages posted on RCGroups that may provide you with conflicting and confusing information if you are unable to discriminate between what applies to this radio and what does not . That is the main reason I have edited this manual, to provide you (and me) with a concise set of information that applies to ONLY this radio.
Post #1 – Introduction
Post #2 – Quick Start Guide
Post #3 – More specific details
Post #4 – Index to other posts and other threads
Please make additional posts to this thread if you have corrections, suggestions, or comments.
The HK-T4A is sure to undergo some manufacturing changes as time goes on – please post your observations if you have this radio and it does not match, exactly, what is described here. I will attempt to make changes and additions appropriate to your comments.
Here is a very readable "review" I just found of this radio: (version 1)
Quick Start Guide
POST #2 QUICK START GUIDE
[If you are an experienced RCer, you may want to skip this post - it is aimed that the newbie who should check out the new radio to see if it works before installing it in a model]
Here are the items that are shipped to you:
OLD VERSION 1 RADIO
NEW VERSION 2 DIFFERENCES > "v2" label on transmitter and orange shrink wrap on dipole antenna end of the single receiver.
Please see Post #252 to find out what is under the orange shrink wrap. http://www.rcgroups.com/forums/showp...&postcount=252
You will need for initial testing:
Eight AA Alkaline Cells (leave the issue of rechargeable batteries until later)
One receiver battery – 4.8 to 6 volts
Insert 8 fresh alkaline batteries into the rear compartment of the radio oriented as shown by the + and - marks molded into the compartment wall.
Turn on the Transmitter.
You should see the LED on the front panel glow green.
Turn off the transmitter.
Connect the Binding Plug to the three pins in the BAT position on the main receiver. (See picture below)
Connect the receiver battery (NO GREATER THAN 6 VOLTS) to any other of the three pin positions with the negative side (usually black) toward the edge of the Receiver and the +voltage to the middle pin as shown in the picture.
GET THIS RIGHT, TOO - EITHER OF THESE MISTAKES WILL SURELY BLOW THE RECEIVER
[If you do not have an appropriate voltage battery, you have probably bought a model kit that provides the correct voltage to the receiver through an Electronic Speed Controller (ESC) - the ESC contains a BEC (battery eliminator circuit) to reduce the voltage from a higher voltage to the proper voltage. You should borrow a proper , less than 6v. battery from a friend. If you don't, you are presented with a "chicken and egg" problem - you will be simultaneously trying to setup and test both your model and your radio at the same time - that is difficult for a newbie since there are possible conflicting issues with setting up the radio and setting up the ESC and motor for the first time - GET HELP]. Of course, if you already have a working model for which you are just changing radios, all you need to do is plug the ESC into the Rx for your testing - no problem. However, you might be a complete newbie with this new radio and a new model - then you will need help.
You should now see an LED on both the main and the satellite receivers blink.
They are sometimes hard to see because they are hidden inside the case, which is a dark, translucent plastic. It is kind of like looking at someone smoking a cigar who is inside of a SUV which has dark tinted windows.
These pictures should help you locate them.
Pick up your transmitter,
hold down the "BIND RANGE TEST" button - don't release it,
Turn on the transmitter power while watching both LEDs blink on the receivers.
When the two receiver LEDs stop blinking and stay lit you may release the BIND button.
The receiver is now bound to YOUR transmitter and will only respond to commands from THAT transmitter.
Disconnect the battery from the receiver
unplug the binding plug and put it in a safe place - you will not use it often (if ever). But if you do need it - you need it NOW.
Turn off the Transmitter.
Plug a servo into the CH1 location on the receiver.
Turn on your transmitter.
Plug in the battery into the receiver BAT position- again with the neg. lead next to the edge of the case and the positive lead in the center pin.
Always do it in this order - turn on Tx then turn on Rx.
The only time you do it in the reverse order is when you are BINDING.
Move the CHANNEL #1 control stick on the Tx to see if the servo rotates about 90 degrees or so. Move the trim control for CH1 to see if it causes the servo to rotate a few more degrees. Move the CH1 "REV-NOR" switch to the opposite position. Again, move the CH1 control stick to ensure that the direction of rotation of the servo is reversed. [Note: This is for the "Mode 2" version. If you have the Mode 1 version (throttle on right stick) you will have to experiment to find what the relationship is between the control stick, REV switch, and the CH#? connector on the Rx - some of us who use multiple radios, find this issue confusing enough that we place masking tape on the radio with a diagram on it showing which control is which]
Control layout for "Mode 2" transmitter
Now, move the servo to the next connector and repeat the above tests.
All four channels should behave the same.
If so, congratulations! You will not have to send the radio back to be replaced
Post #3 – More specific details
WHAT THIS RADIO SET WILL NOT DO.
Compatibility - The transmitter may not be used with other brands of receivers and the receiver may not be used with other brands of transmitters. EDIT: see message 195 for some exceptions to this.
It is not dual frequency (like Spektrum DSM or DSM2).
It is not frequency hopping (like FASST radios). EDIT: version 2 DOES employ frequency hopping
Distance (range) of use - since it only transmits on one frequency (even though it has two receivers) it is not as immune to interference and path of signal problems as the high priced radios. And it is not as powerful as the other radios. For those two reasons this radio set should be used only for limited range models - parkflyers, indoor flight, boats, cars, and robots. I have controlled a sailboat over 700 feet away with the satellite Rx disconnected (see post #109)
Even though it has a button labeled "RANGE TEST", there is no range test feature. On the earliest versions you could remove the transmitter antenna to, sort of, do a range test. But the later versions have the antenna permantly fastened.
Programmability - it is not, in any way, programmable. It does not have exponential rates, control mixing (elevon, v-tail, etc.). And for setting the NOR/REV setting for each control, you must manually adjust front panel switches as you move from using it with one model to another.
Failsafe - when the receiver loses the signal from the transmitter, in more expensive radios, the servos are driven to a "fail safe" position. Not so with this radio. When that condition exists the receiver stops sending a position signal to the all servos except channel #4. Channel #4 is driven to center position and all the other servos go limp (no force on the lever arm).
External Power - If you want to use a wall wart to power the radio, you are out of luck because the external power jack is wired to JUST charge the batteries, if you decide to use rechargeable batteries instead of alkaline .
WHAT YOU CAN DO WITH THIS RADIO
A second binding plug is provided (not provided with version 2) so that, if you have a model with the proper external on/off switch and charging port, you may bind the receiver to the transmitter with out having to access the receiver - you just plug the special binding plug into the charging port, instead.
Normal binding plug on right.
Special charging port binding plug on left.
All but the vary earliest versions of the receiver are equipped with an antenna on the end of a coaxial cable, so that you may have more latitude in positioning the antenna in a model that has limited space to do so. The last one inch of the cable is the active antenna and the rest of the cable is just for convenience. So only the last inch needs to oriented properly for the best communication. The two antennas should be set at right angles to each other for the best results. If you are not concerned about distance problems and are concerned about very small space in which to install, it is possible to remove the satellite receiver and just go it with one receiver.
Early, short antenna EDIT: version 2 is provided with a short antenna that is a folded dipole and it is the last fatter section of the antenna that is the active part.
Later, long antenna
Closeup of long antenna tip
The lights on both the main and satellite receivers should blink when in the binding mode.
They should be off if either: there is no power or the receiver does not find a signal from the Tx.
They should both be on constantly if there is a good signal from the Tx. Sometimes it takes a few seconds for the receiver to find the proper Tx and make the connection.
Battery warning lights, batteries, and rechargeable batteries and powering from a wall wart:
The green/yellow/red-blinking power light on the Tx is calibrated to work best with alkaline batteries.
With the power switch on, the light glows green if the voltage is above 9.8 volts, glows yellow if the voltage is between 9.8 and 8.8 volts, and blinks red if the voltage drops below 8.8 volts.
The current draw is about 175 milliamps.
It is easy to use NiCad or NiMH batteries. They just plug in like the alkalines do. However, there are two concerns when using them. One is the warning light indication and the other is that you will need an appropriate charger - it isn't supplied by the manufacturer.
The yellow light will probably light up to soon after you start to fly because these batteries are of lower voltage than the alkalines. So when you get a blinking red light you should land REAL soon.
If you do not remover the batteries to recharge them in an external charger, you will need a "wall wart" type charger of the proper polarity, and current rating. It needs to be 12 volts. The polarity is REAL important - it must have positive voltage on the center contact of the connecter. The appropriate current rating is about 1/10 of the capacity of the batteries you choose. For example, if you use 2000 mah batteries your charger should provide about 200 ma of current at 12 volts. For fully discharged batteries it will take about 10 - 15 hours for a recharge. It is best not to let them charge longer than that. If you would like to leave the batteries on continuous charge (for days) it would be best to use a charger that is about 1/20 of the rated battery capacity.
If you want to use a wall wart to power the radio, you are out of luck because the external power jack is wired to JUST charge the batteries.[/URL].
Post #4 – Guide to other posts and other threads
Now, for the more adventuresome, I will point you to places that you can find information you will need to get your hands dirty with soldering and all that stuff. The long thread that contains most information of importance to you is here [Careful - it also contains lots of information that applies, also, to some other related radios and does not apply to your radio]
It's up to over 1300 posts in a pretty short time!
You will want to read the rest of this thread, as well as the long, more diverse thread.
You might want to start with this post #19 and then come back to post #5.
to get all the questions answered that are posed below
What is that connector on the back of the case that is labelled TRAINER.
Beware: These pin assignments are ONLY for the 4 channel radio - the six and nine channel versions are different pin outs and mixing them up may fry your radio.
You may find the O'scope waveforms you expect to see on pins #4 and #1 in these, later, messages:
http://www.rcgroups.com/forums/showp...&postcount=320 - Thanks to unisev
The jack accepts a S-Video plug (or you can modify a PS/2 mouse plug to fit). So by making a cable(s) you may connect you radio up to a computer and practice at home using a simulator program on your PC (posts # 84, 86,and 87). Or you can wire it to another radio to be used with an instructor that will be able to hand over control of his airplane to you - however this requires significant modification because, among other issues, there is no switch installed that will allow the instructor to grab control away from the student if the student gets in trouble. http://www.rcgroups.com/forums/showt...2#post12898172
In post #105 "crucial" reports a link to the cable he uses for connecting to a computer flight simulator:
EDIT: OLD HK LINK REMOVED - wjbite.
Some have reduced the number of battery cells to four from eight.
After all this new technology really needs only 5 volts to operate, so why not.
It seems like the redesign for the new technology, in this case, ignored the lack of need for higher voltage.
Modifying the voltage thresholds for the battery charge status LEDs:
Since you may be using rechargeable batteries (or even just 4 batteries) you might want to modify the voltage thresholds for your chosen batteries to cause the lights to indicate more appropriate voltage levels .
Start your search here:
Or if you plan to use a 2s LiPO battery here is a link to the solution to message #284 in this thread:
Throttle stick mods:
If you want to move the throttle stick from the left to the right or vice versa (Mode 2 to Mode 1) you can learn to do it here.
Look at post #19 again.
If you want to increase the physical travel of the throttle stick (I need it for the sail control of my sail boats)
Look at message #119.
EDIT: For version 2 of this radio the stick gimbals are constructed differently than for the earlier versions.
So look at messages #294 and 300 to see how to modify them.
Maybe you have a one or two thousand dollar radio that "walks, talks, and crawls on it belly like a reptile" but is NOT 2.4 GHz - don't despair - here is lots of great information on how to buy this cheap radio - take the 2.4 GHz transmitting module out of it - and install it into your super radio. Uses the expensive computerised features of your old radio and allows you to have the 2.4 GHz advantage of MUCH less hassle with interference and having your radio impounded at the flying field.
Idiot's guide to hacking these radios:
NOTE: ALL POSTS, THROUGH POST #63, BELOW WERE WRITTEN BEFORE THE FOUR POSTS, ABOVE WERE WRITTEN.
We discussed the 4 channel HK radio in this thread. Later the thread wound up being mostly about the Turborix 6 channel. But we did go into a lot of detail on the HK 4 channel still. Schematics too.
Joined Mar 2005
The TX's green LED meaning >9.3 v means it would be on for the full USEFUL charge of 8 cell NiCd/NiMh. 8 NiCd/NiMh cells will peak about 11 volts. They will hold OVER the "nominal" 1.2 v for most of the useful charge.
If using NiCd/NiMh and the green LED goes out... land immediately, you won't have long left before you have just a red LED, rapidly followed by non-functioning controls.
The green LED going out when using Alkalines would = prepare for impact. To get that low with 8 Alkalines means they are DEAD.
It is my hope that those who delve into this above mentioned thread will bring all the info that they find that is SPECIFIC AND BASIC to the use of this radio set to this thread.
I believe that this thread would be quite useful to those of us who don't understand many of the posts on the other thread - it seems to be hard to separate out the basic info from the other radio when one does not understand the highly technical nature of what is being discussed there.
I guess I could state that more simply if I said:
I hope this thread will become a useful user manual for what looks like a low level radio that is a breakthrough in price (albeit, shipped with absolutely no manual )
Thanks, also to fhhuber for the useful info.
Mystery binding plug?
All four of my receivers (one with the Tx and three extras) came with the binding plugs shown in the picture.
The female plug is what I expected.
But, with its leads intertwined with the female plug, a male plug of the Futaba shape was included.
I don't know what this is supposed to be used for. I can only assume that in a low cost product like this the designer would not spend money on something that was not useful.
Can anyone tell me what its intended use might be? UPDATE - SEE MESSAGE #9
Joined Mar 2005
JR/Spektrum also supplies the 2 styles of bind plugs with thier 7 and 9 ch 2.4 ghz RXs.
The second plug is for use with the heavy duty switch being plugged intot the batt-bind port. The 3rd wire IS active on this switch. Thus you can plug in to bind via the charge port.
HobbyKing has two USB cables available.
EDIT: BAD LINKS REMOVED - wjbite.
They sell them for programming the 6 channel radio.
As far as we know, the 4 channel radio is not programmable. The six channel radio seems to require programming because it does not have reversing switches on the case.
Could it be possible that these cables will provide the connection through the "TRAINER" port that will allow us to use simulator software.
Maybe our electronic savvy friends who have hacked this radio will have some idea if it is possible, by looking at the schematics.
OR maybe they have a cable and can try it out, eh?
[ANSWERED IN MANY LATER POSTS]
I fly my Alkaline Batteries till the red flashing light comes on... As many sets as I have put through the transmitter, I'd say it's no fluke... And the Orange light last about as long as the green light... not that I really timed it... but seems that way to me...
Could you give me a link to info on the radio you are referring to, please.
USA, NH, Concord
Joined Oct 2004
Works with Phoenix
The included programming cable (different from the sim cable) is probably equivalent to the HK-TR6A Win2000/XP cable. It works fine with Vista using the right driver. Google mycoolheli and I think you'll find it.
My problem is that I have not yet learned to set the endpoints and servo directions and throttle curves and what-not for the different models in Phoenix. The program used to configure those settings, t6config.exe, seems to work just fine. Once I get that all sorted out I'm going to try to use the transmitter with FSX.
I would be a very happy camper if someone could point me toward a t6config.exe config file for a T-rex 450.
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