Opinion on DX7 vs. 9CHP

[sireric]

Hey.

Don't want to start a war, but I'm thinking about upgrading my 6EXCH to either a futaba 9chp or DX7. I want a lot more control on the head setup, plus timers, at the very least. Programming the servo movements would be a plus too.

I've only had 1 glitch so far (using PCM), and that was before the dean's antenna. Things seem pretty glitch free up to 1000' (my "max" range). Howerver, the appeal of 2.4G is interesting, as well as pretty much getting rid of any big antenna.

Has anyone gone from a 9chp to a DX7? Or considered both and selected 9CHP?

Thanks!

[Jermo]

I only know what I've read about these radios.
My opinion is the DX7 is the better choice from a technolgy stand point. It uses Spread Spectrum (Frequency hopping I believe as apposed to direct frequency), uses 2.4GHz, and uses a digital encoding method on dual channels to ensure communications.

As a communications person the DX7 wins even if it had fewer features (which I don't believe it does.)
Jermo

[spork]

The DX7 has another major benefit in addition to no glitching... you don't need to wait for your freq. pin. As far as the feature set compares to the 9CHP I can't comment except to say the DX7 is supposed to be full-featured. I think kgfly can tell you everything there is to know about the DX7. Also, you could probably download the manual for each.

[kgfly]

Good suggestion Spork. I suggest you browse through the feature summaries on the mfrs websites and download the manuals if you want a more in depth look.

The DX7 (~$310) is an excellent mid-range 7-ch computer radio with a very nice user interface and lots of plane/heli features. It has phenominally low (and consistant) latency and unique features like ModelMatch (cannot fly an aircraft with the wrong model selected in the Tx) and ServoSynch (reorders channels in the Tx frame so that mixed channels are output together, a big advantage for CCPM). It comes with a 1500mAh Tx battery which given the exceptionally low power consumption (another benefit of DSM/DSM2) will last for at least 8 to 10 hours continuous operation.

The 9CHPS (~$650) is an excellent mid-range 9-ch computer radio with a good user interface (by reputation, I have not played with one and the LCD looks to me to be smaller and lower resolution than the DX7's) and lots of plane/heli/glider features. Note that if you are going with the 9C I believe you should get the "super" as it is higher performance. The 9C definitely has the edge on features (eg more timers and glider modes), the question is whether you need/want them. It comes with a puny 700mAh battery and since FM (PPM/PCM)radios are 1W RF and the Spektrum is only 100mW (yes, don't worry, that's for full range operation) this is a pain and explains the booming market in higher capacity batteries after-market.

So, if you don't need (or just want) 9 channels or glider features then I would say the DX7 is a pretty compelling and excellent value proposition. You get:

* A great 7ch computer radio
* The most secure R/C RF link ever
* No risk of shootdowns, ever
* No RF glitches, ever
* Low latency/high performance (better than almost any other system, even those costing up to 8 time more and way better than a 9C, http://www.rcgroups.com/forums/showthread.php?t=604621, take a look at posts 382 and on down)
* Long run time with the stock battery
* No more channel/frequency management, ever
* Tiny, light Rx with tiny antennae
* No more waiting for you channel to come free, ever

If you decide the 9C is better suited to your need, then consider buying the Tx-only and a flight pack from here (should be available in the new year): http://www.xtremepowersystems.net/

For more opinions search here or on rcgroups for DX7, you will find plenty of feedback. I would say 95% positive to superlative. The negatives are mostly from people used to high end Tx (9303, 12z/14mz or some 9C) that are disappointed at a missing feature, glider pilots who can achieve most, but not all they want using the 6 Pmixes and one PITA called kgfly whinging about them not being convertable between mode1 and mode2. :lol:

Hope that's some help, happy shopping.

[kgfly]

Some other general factors to consider:

* What do others you fly with use ? Will you be seeking help with programming/setup ? If so, having the same radio makes it easier.

* Do you want to buddy-box with anyone ? You need the same radio (at least the same brand/series).

And one more opinion, if you are looking at the 9C you should also look at the JR9303 (aka 9xII). They are both excellent radios. The 9303 has a slight edge in most comparisons and surveys. Get your hands on them in a shop or from mates just to see what feels better in your hands.

[sireric]

Thanks for all the good advice!

[BAyres]

Hey Guys,
Another question...I just convinced my father in law to start flying also. He is getting a DX7 for Christmas and wants a compatable buddy box. Which buddy box is compatable with the DX7, I cant find it on the webpage or manual! JR I am guessing...

Thanks and Merry Christmas Guys!

Bob

[spork]

I don't know if it's compatible with JR, but we did a DX7 today with a DX6. Maybe that's too obvious.

[sireric]

btw, I finally flew with DX7 today. A big step up from the 6exh.

Positive:
-Very fast responses -- Less lag than before, so quicker to respond.
-Finally a timer!
-Subtrim got me perfectly level horns (very close before)
-Pretty easy setup
-Mapped channels easily to new unit, using gyro gain = aux2 and Pitch = aux1
-Lots and lots of features

Some Negatives:
-Weight of unit is off (Wish it hung horizontally when on neck hook)
-Gyro gain is now 0-100 instead of -100 to +100 (need to divide desired gain by 2 and add 50)
-Gyro gain control is not obvious -- Not much instruction on this -- I wanted aux2 switch to go from HH to regular, but could not get it to work
-Manual is "good", but certainly not great (nothing about setting up receiver and a few other items).
-I extended out the sticks, but I think I liked the futaba ones better.

Overall, this is a nice step up for me. I'll have to fly a bunch more. Went through 3 batteries today; but I also had a little accident, when I was on the ground but at 50% throttle, I must of hit a stick to get it to tip over (broken props and lost 1 link rod) as I was studying some setting.

[kgfly]

-Gyro gain is now 0-100 instead of -100 to +100 (need to divide desired gain by 2 and add 50)
-Gyro gain control is not obvious -- Not much instruction on this -- I wanted aux2 switch to go from HH to regular, but could not get it to work
Try disabling the gyro settings, using the endpoints on the gear channel and hooking the gear channel to the switch.

[Raydee]

-Gyro gain is now 0-100 instead of -100 to +100 (need to divide desired gain by 2 and add 50)
-Gyro gain control is not obvious -- Not much instruction on this -- I wanted aux2 switch to go from HH to regular, but could not get it to work
Try disabling the gyro settings, using the endpoints on the gear channel and hooking the gear channel to the switch.

I noticed that the end points are -150 to +150 on the Spektrum. Compared to the 9C that threw me off and I ended up flying my heli with a gyro gain that was way too low. If you had a 9C before there is a small learning curve once you switch to the Spektrum/JR radio.

[nregjeb]

DX7.....

much...much, much faster radio. Plus all the other advantages people have listed so far.


I just made the switch from 9CH to DX7. The only thing I miss is the timer starting on Throttle stick position. Every thing else I have been able to get working as good or better then the 9ch.

I am just starting to play with swash 'expo' setting. (another fearure of JR type programming). Available on the DX7.

[Steve Rogers]

Being the owner of both as well there are a couple of features missing from the DX 7 that the 9C has that I will miss. I miss being able to assign more swithches and the 9C has an Alievator function that allows the use of 2 servos on the elevator of larger planks on 2 seperate channels. Which for helis that is no big deal. Also owning a Spektruminized 6102 I missed the timmers now the DX7 has them but there are pluses & minuses. The 9C had 2 timers (like the DX7) one for flight & one total on the radio. The DX 7 has a flight & an intergrated timer I believe they call it that will keep time on each modle. I wiss it had three - flight , total (on the radio) & one to keep track of each model.
All In All I like both tx's but for the ease of no pins I like the DX7

[WillJames]

Good comparison info Steve, thank you!! :noteworthy