RC Transmitter Ruminations…

aileronoff

I recently had to send my Spektrum DX8 into for a warrantee repair of an aileron pot which is shown  above with the stick centered.  Flicking the stick would eventually bring it back to center.  Like any equipment failure does, this got me to question my purchase a bit and it made me really look long and hard at the transmitter market. ( My failure appears to be one that reoccurs for many people and I don’t like being without a transmitter. )

At the moment I’m having trouble looking at anything other than Futaba and JR. This is a VERY religious topic, but I’ll will try to walk through my thought process.

First of all for a heli pilot who has no buy in to any system, I would definitely pick the Futaba 8FG in a heartbeat.  It is priced well, performs well and has a great track record for reliability. There really is no downside if you can fly everything you have with Futaba receivers and are comfortable with the ergonomics. I personally like JR ergonomics better, but that is a personal preference.

Flying with the same transmitter all the time seems safer than switching around.   When you get into trouble the last thing you want to do is go for a switch that is in a different position on a different transmitter. Since I’m flying an mCPX at home more than anything at the air field, this has a distinct impact on my decision.

That said I have bought into the DSM2/DSMX family for a couple reasons.

  1. The Blade mCPX.  This a big reason for me. I want the ability to use the same transmitter all the time, and this little heli allows me to  fly acrobatics in my back yard without putting my neighbors or my wallet in danger.
  2. My Skookum SK-720 electronic flybarless system will run as a receiver and use 2 DSMX satellites  directly. This is a very clean system. Anything else requires a separate receiver which means more wires and another point of failure.

So why did I buy a DX8 to begin with?

The main reason was to fly my mCPX’s. However I was lured by the telemetry as well. My feeling now is that the DX8 is a whole lot of transmitter for the money, but it is built to a price point where more compromises than I would like were made and it has some reliability issues. Some people are very happy with the DX8’s, and others are not. I fall into the latter category.

So where does this leave me now?

JR11X

I purchased a JR 11X because it is a reliable full featured transmitter that is DSM2/DSMX compatible. It has all the bells and whistles and I shouldn’t have any problems with it. It doesn’t have telemetry, but if I really want telemetry I can get a Spectrum TR1000 for an Apple iTouch that will bind to my TM1000 and give me telemetry in color.

e6_stmri1000_telemetry_interface

Having just purchased a second transmitter this year, I hate  to say that there are lots of new developments going on right now and this is really a bad time to buy a transmitter.  If you can wait I would say to do so. There is a lot of settling out that is going to happen in the next few years.

From what I can see JR’s new DMSS looks like the new communication standard to beat.

DMSS
•    3 GHz bandwidth for frequency hopping vs. 1GHz for DSMX/FAAST
•    96 channels vs. 24 channels to switch between
•    channel binning ( ie. swash  Aileron, Pitch, Collective sent together in a single packet ) = smoother control
•    2 way communication with telemetry in the receiver.
•    Receiver/BEC voltage out of the box without additional sensors, plus numerous additional sensors that are just starting to become available.

Their new transmitters XG7/XG8 are priced below the DX8

•    7/8 channel transmitters
•    11ms frame rate / 4096 steps for digital servos that can handle it.
•    comes with receiver with satellite, receiver battery telemetry out of the box ( additional sensors available  )
•    LiFe battery  ( nice!!! I wish all Transmitters came with this )

So the frame rate is the same as a DX8 or twice the 22ms of the JR 11X that I just purchased.  The resolution is good for bragging rights only. No transmitter can really give you 2048 never mind 4096 steps of resolution at the moment.

My guess is that JR is testing DMSS out at the low end and will trickle up to their top of the line models only after DMSS has proven itself. 

I really think the bi-directionality of the DMSS protocol is very interesting and making a separate telemetry module unnecessary is a really nice feature.

Politics

This is a bit of a hot potato right now. Horizon Hobby has no plans to release the JR XG7 or 8 in the US currently, but there are places overseas where you can order one if you really want one. The big question is how to handle warrantee issues if they ever come up if you are a US RC person.

So I’m curious if JR will run DSMX in the US only and DMSS for the rest of the world since DMSS competes with Spectrum’s DSMX, which means it won’t support all of Horizon Hobby’s BNF aircraft, etc..

In the mean time I’m just going to use my JR 11X on my heli’s and relegate my DX8 for use by my kids for their 3D RC Foamies that are made to fall out of the sky.  Maybe that’s a bit harsh, but once you don’t trust a piece of equipment, either you repurpose the equipment or you get rid of it.

Advertisements

0 Responses to “RC Transmitter Ruminations…”



  1. Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s





%d bloggers like this: