airflow

My Feedback: (1)

Just put my brand new DX6 on trickle and started looking through the forums for DX6 info. Couldn't find any significant problems, and I'm feeling like it will turn out to be a good way to fly some park flyers. The battery that came with the DX6 is a 600 mah nicd. Remembering my 8103 battery and how useful it was to put in a liitle more capacity, I'm considering upgrading the capacity. I ran across a note about changing the voltage regulator, and checked out
http://www.dimensionengineering.com/...ektrum_mod.htm
Being familiar with soldering (I've had 40 years experience doing that for a living) I'm considering doing this modification (even though I suspect the warranty would be voided). I am curious about your opinion on this modification.

dsnyder

That is not recommended or advised to do, and you are correct, the warranty of the system would be void. It is also a violation of FCC regulations.

gwh

Danny,

Please elaborate more on why this is a violation of FCC regulations.

hilgert

My Feedback: (2)

Because it would increase the runtime and functionality of the radio, therefore making it more useful. So, obviously, it would violate FCC regulations.

CFR Title 47 Part 15 Section 23 states:

§ 15.23 Home-built devices.
(a) Equipment authorization is not
required for devices that are not marketed,
are not constructed from a kit,
and are built in quantities of five or
less for personal use.
(b) It is recognized that the individual
builder of home-built equipment
may not possess the means to perform
the measurements for determining
compliance with the regulations. In
this case, the builder is expected to employ
good engineering practices to
meet the specified technical standards
to the greatest extent practicable. The
provisions of § 15.5 apply to this equipment.

This is *NOT* a Part 95 device (eg - it's not "old school" rules). Part 15 is *way* more flexible in this regard.

hilgert

My Feedback: (2)

So is crystal-swapping by "non-qualiifed" persons, yet Horizon and others will happily sell crystals to end users without question. I'm not saying this is bad (it's actually quite practical), just that it is against FCC regulations (not selling them, but a non-qualified user changing them).

Part of the reason for doing the voltage regulator mod is the silly decision to put in a linear regulator in the first place that wastes half the power it draws, cutting runtime in half. The two flaws I see in the DX6 are the regulator and the POS radio it was put in. I think people would have paid $50 more to have it in a 6102, and toss in a switching regulator to boot. THEN there would not be nearly as much effort put into modifiying the base setup. I guess the only other thing I would do is increase the power output on the Unigen module to 100mw (I have heard conflicting stories on just what the actual power output is).

Don't get me wrong. I am a HUGE proponent (and defender) of the Spektrum system. I have seen some of the "others" out there, and I still think Spektrum got the SYSTEM right on the first try, just not the delivery (POS TX and linear regulator). Also, with the two RX antennas, you have addressed the diversity problem as well.

adams-RCU

Hilgart, Could you please give me a call at 217-352-1913. John Adams

hilgert

My Feedback: (2)

Tried calling - no "adams" in the company phone directory. Check your PM...

airflow

My Feedback: (1)

it's illegal to change crystals in rc transmitters -
contrary to or in violation of a law : ILLICIT, UNLAWFUL

here's links to the code

95.645 Control accessibility
http://www.nsea.com/PART95/95.645.txt

95.218 (R/C Rule 18) What are the penalties for violating these rules?
(up to $10,000 or 1 year in jail or both)
http://nsea.com/PART95/95.218.txt

Snyder has it right about the modification also. Modifying any transmitter will void the FCC certificate.

p.s. It would be a good idea to void all above comments by Hilgert.

hilgert

My Feedback: (2)

Yes, please do - and stop all innovation. Also, please do not roll through stop signs.

By the way, this is ***NOT*** a Part 95 device like our older narrow band radios. It is covered under Part 15 (spread spectrum). Not sure if you were implying that or not, or if you were just re-stating what I had already said before.

This modificiation (doubling battery life) does not change any characteristic of the RF output in any way that is measurable (except, of course, that the output can stay on LONGER since the battery last longer). If the output was changed somehow, then it would mean that the RF deck was in violation in the first place (prior to the mod).

I applaud the folks at DE for coming up with this.

Again, the Spektrum system is the BEST thing out there in terms of glitch-free flying. Hopefully they are paying attention to all of the modifications taking place and perhaps considering improvements based on those mods. AND, hopefully, they are considering making MODULES for JR and Futaba TX's as well, which would essentially negate the need for most/all of these modifications.

airflow

My Feedback: (1)

I understand the desire to improve the DX6, and I appreciate the need to defend the existing product. Originally I asked merely for an "opinion" and I believe that is what we received, although it was a very short reply. It's up to the factory reps to supply an explanation for the opinion; such an explanation would clarify the situation. If clarification isn't forthcoming, then the gods have spoken. Thanks, Hilgert, for staying on subject.

adams-RCU

Gentlemen, The DX6’s current consumption is 280ma. The included 600mAh battery offers just over 2 hours of run time. If more flight time is needed a 1500mAh transmitter battery is available under the Expert brand that will extend flight times to over 5 hours. Soon we will be releasing a 2700mAh pack under the JR brand that will offer over 9 hours of flight time when used in the DX6.
Officially Horizon Hobby strongly encourages customer to not modify JR, E-Flight or Spektrum radios for obvious responsible reasons. The potential for serious property and sever physical damage caused from an out of control model is very real. While the modifications that Hilgert is advocating, when correctly done and tested by qualified technicians indeed do work, the probability of a non-qualified individual making a mistake (cold solder joint, reverse polarity, etc,) is very high. In fact our service center has been receiving several calls per week from customers that have attempted these modification and have rendered their radios inoperable.
Like most products the DX6 was designed to meet a price point. Adding a thirteen-dollar switching regulator and upping the features would have significantly increased the cost of the system. We are working on more sophisticated systems that will likely come closer to meeting Hilgert’s expectations however these systems will be more expensive. In the mean time if you desire more flight time, I recommend that you look into one of the larger capacity packs that are available. Adding a high capacity pack won’t void your warrantee and there is no question that doing so is FCC legal.

John Adams
Technical Director
Horizon Hobby
Spektrum

hilgert

My Feedback: (2)

My first response was to indicate that this is a Part 15 device, and Part 15 rules are more "relaxed" that part 95 rules. Specifically, Sectino 23 indicates to me that as long as you are not marketing or selling modified units it seems to me you would be okay with the mod from an FCC standpoint. Other sections in Part 15 talk about interference, etc. The FCC will *NOT* come and arrest or fine you for *any* modification to *any* Part 15 device if it does not cause interference outside of it's normal operating parameters. So, if you do the mod, and nothing fundamental changes in RF output, etc., even if someone tattles on you the FCC does not care as long as there is no interference. In other words, in this regard, the FCC cares about EFFECT and not CAUSE.

My second response was specific to THIS modification. It was stated that this mod is not recommened or advised. Has anyone felt the heat generated by the linear regulator on the DX6 RF deck? It gets HOT, and that means wasted energy. One of the single largest complaints in the early threads (at least on RCGroups.com) was the short runtime of the TX - good for a couple of flights only. This SIMPLE and EXCELLENT modification more than doubles runtime, and I applaud the folks at DE for coming up with it.

HOWEVER, as John correctly states, if this is done in an improper manner you can end up with a fried system, or even worse a loose/cold solder joint (or torn pcb trace) that could casue intermittent problems (I'd rather have it work or not work, and nothing in-between). This is a HOMEBREW modification, not a PRODUCTION modification. If you are not comfortable solderiong and working with electronics, then the mod is not for you. And, as with ANY mod, the owner assumes all risk.

To be clear, I am not pushing this modification. I think it's great, many have done it and like it, it works and it's cheaper than a new battery pack. In production the cost of a switching supply would be way less than the $12 DE charges, by the way.

ANY modification we make to our TX's, RX's, planes, motors, props, chargers, etc. involves owner-assumed risk. If you can't do it right, then it should not be done. But if you CAN do it right, and are willing to void the warranty, then it does help to push the envelope of the hobby forward.

As I stated before, I hope Horizon and others are seeing just how popular many of these mods are (power mod, module mod for using in 7-8-9 channel TX's, 6102 mod, etc.), and will in turn incorporate them into production units that eliminate the need for such mods.

-Hilgert

airflow

My Feedback: (1)

Just finished a run-time test on my DX6. Close to 3 hours on the supplied 600mah nicd. I really feel I lost about that much time looking at the various forums here and RC Groups. If I find more time to fly the parkflyers, I may replace the battery with a higher capacity JR Extra nicd. I believe Spektrum did it right, and the price of $200 for Tx, Rx, and 4 Servos is more than fair.

hilgert

My Feedback: (2)

Well, at 280mah for the RX, and a 600mah battery, you must have just charged the battery (just simple physics and math here - no conjecture). These batteries (this is not unique to Spektrum) loose a non-trivial amount of their charge in the first day or two, and slowely die over time after that. Many people like to keep a TX and plane in the car to get in a flight or two on the way home from work, at lunch, etc., and having to constantly worry about charging the battery can be a pain. Certainly a larger capacity battery would help, but for only $12 (IF YOU HAVE THE SKILLS TO DO IT PROPERLY) the DE 3.3V switching regulator is quite a bargan.

The other approach is to put in a 2500mah lipo TX battery (available from commonsenserc.com), or just use TP2100 11.1v 3s1p lipos (ProLites). I use the ProLites in my planes, and they fit with a bit of a squeeze into the battery bay in the JR TX's. Lipos don't have the storage loss problems of NiCd and NiMH batteries, but you do have to watch how you charge them. Again, this is for people that UNDERSTAND lipos only.

Anyway, the point is that a 600mah battery on a system that wastes half of it's power in energy loss is not efficient by any definition of the term "efficient". Adding larger capacity batteries that will STILL waste half of their power on a linear regulator does not make much more sense to me than the stock battery.

The bottom line is that IF YOU HAVE THE SKILLS TO DO IT PROPERLY this modification is a nice mod; if not, then resign yourself to charging every few flights, getting extra batteries or getting a larger battery.

I would encourage everyone to ACTUALLY READ the page on Dimension Engineering's site. It carefully explains the modification, and has some nice before/after data.

hilgert

My Feedback: (2)

Also, to be complete in my statement, I do agree that at TX with the Spektrum RF deck and an AR6000 is a fair deal at $200. The servos are certainly nothing to be desired (many folks have problems with them centering consistently, and about 1/3 of mine jitter all the time with no stick input and no load). To me I am getting a RF deck for $80 that I can transplant into a better radio, an excellent diversity antenna RX for $60, and I can use the S-75 servos for test servos or sell them to someone else (why do they always seem to sell servos with a TX?).

All-in-all, not a bad deal for glitch-free flying. So, I agree, $200 is a fair price for this setup (other than the servos - eesh). Personally, I'd pay double that if the TX was a bit more functional.

To me the original question (going back to that to remain on-topic) was about an opinion (from Spektrum) on the modification. Well, obviously the manufacturer would not endorse a mod to a stock system (I would agree with them on that for legal reasons). Many have done the mod and liked it; I am sure others (as John points out) have done it and were perhaps a bit over their head and mucked it up. In fact, I just read a post where someone used a 5v regulator (ordered the wrong one) and probalby blew their RF deck. So, nothing is fool-proof, as fools can be quite ingenious (having foolishly done such things in the past myself on various thing, but I accept the financial responsibiliy and don't expect the manufacturer to pay for my experimentation).

So, the bottom line is that the mod works as advertised if done properly, but can be disasterous if not done properly. But, this is true of almost any modification - if you don't have the skills to do it right, then don't do it.

airflow

My Feedback: (1)

Thanks, John, well said.

adams-RCU

Two points that I'd like to Clarify. At 280 ma, the DX6 actually draws less current than conventional 72mHz systems which typically draw between 320 to 380ma. Consequently the DX6 actually provides more flight time with the same capacity battery than current 72 mHz systems. Point #2- Every brand and type of 72 mHz transmitter uses a linear voltage regulator. I've been at Horizon for nearly 20 years and have evaluated nearly ever type and brand of radio system on the market and every transmitter that I've encountered has a linear voltage regulator. While it's true that the DX6 uses a lower operating voltage thus the regulator operates under a greater load, the point remains that all currently available transmitters use a linear not a switching regulator.

airflow

My Feedback: (1)

I'm certain that if I invested time and money, I could improve the Spektrum DX6 Transmitter. Having spent 40 years upgrading and updating electronic equipment, I intend to spend the next 40 years adhering to the dictum, "If it ain't broke, don't fix it." My 'unfixed' DX6 is performing superbly every day, thank you. Yes, thank you for providing a reliable product at a reasonable price. [sm=shades_smile.gif]

Thomas B

My Feedback: (4)

I have very recently cheerfully and extensively voided the warranty on my DX6 system by having an electronics guru (who shall temporarily remain nameless....) remove the TX RF board from my DX6, add the translator chip created by Mr. RC Cam over in RC Groups and piggy back the resulting unit in a stand alone removeable module on the back of my Futaba 9CAP.

This was not the first one of these things, even in the DFW area...and you know it will not be the last.

PS. I also did the switching regulator mod a while back, so I have REALLY voided my warrenty....

Please...no admonitions about FCC violations. The Unigen FCC certificatiion used by Spektrum is unaffected by this conversion. None of these mods cause any issues, per Hilgert, above.

Works flawlessly. Put in 6 flights over the past weekend on two models at the big NEAT 2006 event in NY. All I had to do was drop in a DX6 RX in any of my models, select the associated memory from my Futaba 9CAP and all was perfect. there will be more flights at DEAF 2006 this coming weekend.

John Adams, et al at Spektrum: I LOVE the DX-6 technology and I LOVE the DX6 RX unit. I cannot thank you enough for creating such a great radio system and for advancing the state of the art of our hobby in such a great way.

However:

I really hate the fact that you tied it to a creaky old first generation JR computer TX. I do understand WHY you did it that way, but that does not mean I have to like it.
I really hate that you installed such a physically delicate TX antenna and refuse to sell replacements.
I really hate the fact that you chose not to produce a module system for aircraft use compatible with all brands of module radio systems, as you did for the surface car and boat crowd.

Thus, the above gives great motivation for many to fix those problems.

The lack of a switching regulator is not that big of a deal.....I can forgive you for that... Easy to fix for most, anyway. The power supply is an ancillary item that does not affect the FCC cert, in any case..

Please: produce a DX6 module system for my Futaba that works as well as the one I have perched on the back of my 9CAP now, and I will stop using my homebrew conversion tomorrow...

Please: don't pull a "Wright Brothers" scenario where you invent something great and then fail to keep up with developments and desires that force the technology ahead at great speed.

Tom

wings515

I am in the process of purchasing a DX6 and would like to know the restriction associated with the receiver. What is the limitation 'for park flyers only' ? Is it the TxRx distance or servo drive. If it is a distance issue, what controls this limitation. If it is the servos, can an external driver be configured for larger planes with higher servo torque requirements. The Spread Spectrum technology is fantastic and should completely change the RC sport.

Thank you,
Wings515

hilgert

My Feedback: (2)

There is a large thread on this very topic over on RCGroups.com located here:

[link=http://www.rcgroups.com/forums/showthread.php?t=452817]Spektrum DX6 - Actual Field Results[/link]

-Hilgert

rcboosted

Sorry to resurrect this thread, but I have some questions about the DX6. First of all, the battery pack is a 9.6V NiCd pack. Why does the voltage on the display say 11v+ right off the charger? It drops off to 10.9V quickly, but even then, it's still more than the battery pack itself. If I were to put a lipo pack in there, should I only charge the lipo to 10.9v or 9.6v? (9.6v would actually be impossible unless I use a resister to waste that power away) Any ideas?

dsnyder

A fully charged 9.6V battery will be roughly 11.4-11.6, but then quickly fall off when in use. 9.6V is the nominal voltage rating of the pack. Charging a lipo to only 10.9-11V would not really increase your flight time per charge. I'd suggest a larger Nimh if you want more flight time per charge.

JRPB5011 TX 9.6V PACK 2500MAH NIMH SANYO

rcboosted

I'd like to go lipo if possible. (simply because I don't have a nimh charger and the stock charger is way too slow at 50ma) My next question is, how high of a voltage can the DX6 take? If I assume 11.6v is the highest it can take, then I only need to shave off 1v from a 3S lipo pack. Simple V=IR tells me that 1=.28R (1volt and 280mah the DX6 consumes) will give me 3.57ohms for the resistor value. If it can take 12V, I only need 2ohms. Is this correct Danny?

hilgert

My Feedback: (2)

I use 3S1P TP 2100 Prolites in my TX's (XP6102DX and XP9303DX), and they work like a champ. Since I use the same packs in my planes I never run out of power at the field, and I sometimes will swap in a used plane pack (with 10V left) and take the TX pack and fly it. I have also tried the Common Sense RC 3S1P TX lipo battery (many have used this battery, and it fits in like a stock battery) as well. I would *not* do this without the 3.3V switching reg modifcation, but if you have done the mod already then going to a lipo won't void your warranty any more than it already has been. I have also cut off the battery connector from the stock charger and put it on a lipo charger lead (remembering to REVERSE the polarity, as JR uses a center negative pin unlike everything else in the US - wierd). If you are worried about the voltage, just charge to 11.5 volts or something (I don't under-charge, and I have not had any problems).

No guarantees with DIY projects, but many, many folks have done this without ill effect. Some, however, have botched some aspect of the switching reg mod and/or lipo conversion, but that was due to lack of skill/knowledge. Of course, this is true of any modification.

The Common Sense RC pack can be found here: [link=http://www.commonsenserc.com/index.php?cPath=37_27]http://www.commonsenserc.com/index.php?cPath=37_27[/link].

That all said, there are several other alternatives, one of which is pointed-out in a previous post, using NiMH batteries as well. I went that route initially, but found that it added a ton of weight to the TX as well as still having the drainage problem when in storage. Also, the stock TX charger only charges at 50ma, so on a 2500mah NiMH battery it would take 48 hours to charge completely (where my lipo takes just over an hour, and lasts forever in storage).

-Hilgert