General Signal Warning on DX9

[John-007]

Hey guys, I was doing some taxiing tests yesterday morning, my question is:
my plane was about 150m/490 feet away), the TX started to show/beep "Warning Signal" -91 dBm 15%.
So my question is: Does one get less of a signal when the plane is on the ground?
I found some info saying that even wet grass can effect signal range whilst the plane is on the ground at a distance.
Any info would be greatly appreciated. Thanks.

 

[RandyDSok]

The ground can certainly affect your signal but it depends on the topology ( hills and valleys ) as to how much. The 2.4Ghz frequency can be obstructed by many things including parts of the vehicle itself. The engine/motor and battery along with the other electronics has or is made of metal, so they can create a "shadow" if they sit between the receiver(s) and your transmitter. The materials that make up your vehicle can also affect it, for instance carbon fiber blocks radio signals as just one example. The battery levels for both the transmitter as well as the receiver also can affect how much signal they can put out or receive.

 

[John-007]

Thanks Randy for your detailed answer.
The model in test is a Valiant 30cc and the terrain is flat. Batteries were all fully charged. I've also attached the WARNINGS that I'm getting. Thank you again.

 

[Tony]

Air radios do sometimes have issues on the ground if they get too far out. It's just the way the signal is with these things. And 500' does seem quite a ways for an air radio on the ground. I remember watching a video about FPV talking about "Reflections" that had this exact issue.

I am not familiar with the laws 'down under' for radio power, but I know in the EU, they have lower power output than we do here in the states. This will also affect it.

 

[Tony]

Also, check to make sure your antennas are placed correctly. You want one that is vertical and one that is horizontal for best reception.

 

[RandyDSok]

If you actually want to test for this... get someone to watch your warning screen while you are flying. Take off and go up to around 100', fly out to about the same distance and have whomever watch your signal strength as you go further out. Obviously if the signal starts getting low, turn around but remember that your engine ( which isn't a small one relatively speaking ) will also block some of your signal, so take that into account and turn around well ahead of that also being a problem with signal strength.

 

[John-007]

Thank you Tony and RandyDSok for all your suggestions and advice.
This is what I have: AR12310T (12 channels) PowerSafe Telemetry Receiver and 3 Remote Receivers.
I've installed these in the 3 different orientations as per Spektrum instructions.
I'm not too comfortable flying the Valiant with a lot of "Frame" dropouts whilst testing.
So, I was thinking of hanging the fuselage about 6' (2 metres) off the ground and using the "Range Check" function on the DX9, which is about half power and walking away to a distance of a 30 metres/100 feet with line-of-sight.
I'll get my wife to turn the fuselage from front, left, back and right orientation whilst hanging. (Making sure she's not in the way).
Hopefully, these tests will shed some light on the subject.
What do you guys think?

 

[Tony]

Sounds like a plan to me. Getting it up off the ground will definitely stop some reflections. And the higher the better for testing.

The Range Test is a great option so you don't have to go as far.

 

[Fly-n-Low]

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[Admiral]

I am not familiar with the laws 'down under' for radio power, but I know in the EU, they have lower power output than we do here in the states. This will also affect it.

Australia uses the US standard Transmitters, the only ones to my knowledge available in EU standard were the old DX6i which were switchable US or EU in setup.
There maybe some EU Tx's here that came in through Ebay but the label on the back should list EU standards not US Standards.

 

[John-007]

Curious, do you have any remote RX?

Yes, I have 3 satellite receivers. If you look above, I mentioned the specs of what I have. Thank you.

 

[John-007]

Australia uses the US standard Transmitters, the only ones to my knowledge available in EU standard were the old DX6i which were switchable US or EU in setup.
There maybe some EU Tx's here that came in through Ebay but the label on the back should list EU standards not US Standards.

My DX9 says that it's the US version and not to be used in the EU. So I'm good in that respect.
I appreciate everybody's suggestions and question. Thanks.