DX8 Out of Range Issues?

[John Roberts 9]

Having given up trying to resurrect my very old Sanwa radio I decided to buy some 'new technology' in the shape of a Spektrum DX8 & AR8000 Rx.

 

Last week my Irvine 40 Tutor had its maiden flight and almost immediately the model started displaying 'out of range' issues even at pretty modest distances away. The throttle would cut to tick over revs as the failsafe mode kicked in and a second or two later normal service resumed.

 

Initial thoughts were that (as a raw novice) I was making the mistake of accidentally moving the throttle joystick but my club instructor experienced exactly the same problem.

 

Low power range tests on the ground showed that 'out of range' was happening at 15 paces or less (30 is the recommended figure). After conversations with the equipment supplier and Horizon I repositioned/reorientated the two Rx components and this improved the low power range test a little by about 3 paces. Still a long way short of the recommended distance.

 

I have now returned the equipment to Horizon for investigation.

 

Is this an issue that others have experienced or have I just been unlucky? I must admit that my confidence in the equipment has taken a big knock whatever the outcome.

 

Cheers,

John

[FlyinBrian]

Any RC equipment can fail, I am sure Horizon will sort you out quickly.

[John Roberts 9]

Yup, I am sure that Horizon will sort it out quickly - I hear that they have a pretty good reputation for customer service etc. which is reassuring .

 

My reason for posting was really curiosity about whether others had experienced anything similiar with this Tx & Rx and, if so, how the problem was resolved.

 

Cheers,

John

[Pete B]

I haven't heard of any instances like that with the DX8, John. If there is no fault with the radio, the only possibility I could think of would be orientation of the Tx aerial.

 

If it is pointed straight at the Rx, there's a good chance the signal may be lost. Most folk fly with the aerial set 90deg left or right, parallel with the Tx, or angled upwards or downwards at 45deg. These positions ensure signal strength at the model is at the maximum.

 

Horiozon will probably have it back with you within a couple of days, so it will be interesting to hear their diagnosis.

 

Pete

[John Roberts 9]

It is very reassuring that there hasn't been an avalanche of posts all saying "my DX8/AR8000 did that too". Looks as though I have just been unlucky with a rogue radio set.

 

Repositioning the two Rx components so that the larger component was laid hoizontally on the fuelage floor and the second, smaller, Rx component was positioned vertically and at a slightly higher level on one of the fuselage bulkheads did improve things a bit, Pete. Whilst not enough to eliminate the problem it confirms that aerial positioning is important.

 

I will report back once Horizon have had a look.

 

Cheers,

John.

[Peter Jenkins]

John, you might consider buying a Spectrum data logger (around £20) that will show you how well the aerials are coping and how many data frames have been lost (apparently up to 6 is OK) and how many Holds (i.e. Rx not receiving) you have. My experience has been that I have not suffered any data frame losses or holds but lots of aerial "drop outs". I was told that by moving the two Rx's and then comparing the aerial performance and frame losses you should be able to achieve optimum Rx locations. Worth a try if you are feeling a bit concerned about how much trust you should put in the equipment..

[Chris Bott - Moderator]

If you have the telemetry unit, that will send all the data logger information back to the transmitter. I wouldn't look at this while you are flying, but its all still there on the screens after you land.

[Peter Jenkins]

Good point Chris - I don't have that with my DSX9 Tx!

[Tim Mackey]

Not experienced any range issues with mine, and have many different types of receiver.

[John Roberts 9]

Chris / Peter - My DX8 was supplied with the telemetery unit although, as yet, I haven't bothered to connect it (on the grounds that I wanted to keep things as simple as possible until I was a bit more experienced!) but as soon as the set comes back from Horizon I think it might be a good idea to plug it in. The post flight analysis facility will doubtless provide some very interesting information.

 

Thanks to both of you for this useful advice .

 

Cheers,

John

[John Roberts 9]

Well my DX8 arrived back yesterday (impressively fast turn around by Horizon).

 

Their inspection revealed no faults but for safety & peace of mind they replaced the AR8000 Rx and a transmitter RF board FOC - again, impressive customer service.

 

Horizons final conclusion was that it was my installation and/or receiver/aerial positioning at fault.

 

I reinstalled the two Rx components this morning pretty much as they were before - one component laid horizontally on the fuselage floor and the second smaller component mounted vertically on a bulkhead with about 3 inches between the two components. The only real difference to my earlier installation was that I dispensed with the foam padding & elastic bands and used double sided sticky foam pads instead. Low power range tests easily achieved 30 paces (and plenty more!) so problem solved .

 

So, overall, I am delighted that next week (weather permitting) I should be flying again but I still have a nagging question in my head as to why the issue arose in the first place. Odd indeed!

 

Cheers,

John

[Chris Bott - Moderator]

Sounds good John.

 

I'm always a little suspicious if they say they replaced something when there was nothing wrong with it. It's as if they are not allowed to admit that anything is ever faulty.

 

Still, the outcome is positive for you, you seem to have a system that works. That is all that matters.