Relocating the receivers - adding telemetry

While talking to some new friends on the RC Groups forums, I was told of a possible issue with the location of the receivers on the bottom plate of the hex frame.  In the picture to the right you can see that the main receiver (the grey box labeled AR8000) is mounted to the right of the NAZA M controller (the white box with the red label in the center of the plate), and its satellite is mounted to the left of the controller.  Turns out that the construction of the plate that they are mounted to may block radio signals to the receivers.  My new friends advised me that both receivers needed to be relocated to allow the antennas to extend past the airframe so they have the best chance of getting a strong signal from the transmitter.  Time to get to work.

The main receiver has now been moved to the right so that the antenna extends away from the frame between the "left rear" and "left center" motor arms (as viewed from the front of the airframe.)  For those of you who are familiar with the NAZA M designations, this would be between the "motor 3" and "motor 4" arms.  This ended up requiring a complete rewire of the servo connections between the receiver and the controller, but in the end they are a lot more compact and look somwhat neater, so that was time well spent.

The satellite receiver's antennas needed to be placed as close to 180° away from the main antenna as possible and also in the opposite plane.  To accomplish this it has been moved to the top of the "right center" (or "motor 6") motor arm. Fortunately my new buddies over on the RC Groups forums informed me ahead of time that the existing cable that connects the main to the satellite was way too short, so I picked up a longer cable from my local hobby store that did the trick nicely. 

One really nice side benefit of relocating the receivers is that it opens up quite a bit of space for mounting other "stuff" on the bottom plate.  Eventually a PMU-2 module, an iOSD module and a video transmitter will all have to go on this airframe.  Now it looks like there will be plenty of room for all the new "stuff."

I'm fairly pleased with how "stowed away" the servo wiring looks, but the wiring coming to the controller from the ESC's is still a rat's nest that begs some proper dressing.  If I can figure out a way to dress them up short of cutting them to size I will post it for you.  I would like to avoid cutting them if I can. 

Sharp eyed viewers will no doubt notice that I have replaced all the plastic tie-wraps that held things to the frame with removable and reusable eight inch long and 3/4 inch wide velcro tie-wraps.  I saw this on someone else's airframe and it made immediate sense to me, especially when you consider that I'm likely to have this thing apart and back together a lot.  A pair of rolls (in black and grey, 25 straps each) can be bought at your local Home Depot for about six dollars.  You will definitely find multiple uses for these little ties, they are very handy indeed and I highly recommend them.

The radio system came with a telemetry unit that the previous owner had never installed.  The telemetry system transmits things like flight pack (main battery) voltage, temperature, engine RPM and detailed information on the received radio link itself back to the transmitter so it can be viewed in real time or stored in a flight log for later viewing.  I figured that this would be a perfect time to install the telemetry module since I had the airframe taken apart anyway.

The module has a relatively long antenna which also needs to be routed away from the airframe for best performance.  Since I'm planning on having a GoPro on a gimbal installed at the front, I need to make sure that this antenna routs out the rear of the craft to avoid getting it in any pictures.  After some experimentation I realized that the only place I could mount the module (and #1 be able to make the connection to the main receiver using the only cable I had that fit, and #2, being able to route its antenna out the rear of the craft ) was on the upper plate at the rear of the frame between the "motor 4" and "motor 5" arms.  A quick solder connection of the voltage leads to the battery supply, plugging in the data cable and the power "sensor" lead to the module and I'm all set.  Time to button this thing up!

So here we are with the top plate reinstalled and ready for flight and range testing.  I could not resist a "quickie" flight out in the front yard.  The telemetry workd great.  I can now monitor my battery in real time and see the data on fades, dropouts and such - and there was actually nothing to report from that quick test flight, but I cannot make any definitive rage or interference tests from my house.  I need an area with more open space to do a proper range test.  

In addition, after a few test flights from the sidewalk in front of my house I am starting to realize that something in my immediate neighborhood causes the hex to be a little "jumpy", for lack of a better way to put it.  It's nothing drastic, certainly controllable, but the hex will seem to apply a little rudder on its own intermittently, and even with more than enough GPS satellites available it is noticeably not as stable as it is when I fly it away from "civilization" at places like Markham Park or when I was out at Harold Campbell or elsewhere out off of US 27.  I'm presuming that either the receiver is being botherd by the ten or fifteen WiFi routers that are within range of my house (the radio system operates at 2.4 Ghz, the same band as WiFi uses) or its compass is being affected by things like mailboxes and light poles nearby (compass problems could cause the rudder issue), or maybe a combination of both things.  Because of this, any tests for internal interference will also have to wait until I can get a little further away from the house to test.  I'll let you know how it all plays out.

Charlie