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Author Topic: 2.4 ghz radio / range / failsafe  (Read 7749 times)

Brigadair

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2.4 ghz radio / range / failsafe
« on: January 31, 2015, 08:04:38 PM »

Hi guys


Just a quick one.


I realise many model racers are switching to the 2.4 gig band from 27, 40 etc MHz.


Apart from the great advantages of having unique frequencies which should mean each tx is uniquely
connected to the paired Rx, what are the disadvantages?


I'm not sure the 2.4 gig band will go through water, (ie don't run a model sub on it).


I realise the signal won't traverse Kevlar / carbon very well, hence external areals.


My question is, how will a 2.4 gig signal pass through a 1 litre fuel tank sat directly to the starboard side of a radio box, (made of wood or plastic) and an alloy / stainless tuned pipe running to the port side of the radio box.


The rest of the polyester glass fibre hull surrounds all components.


Only reason I ask is that during the 2014 bmprs season, a number of boats cut our without obvious reason, on occasions, possibly due to failsafing?


Any members offering technical info based upon their experiences will be much appreciated.


Thanks.
Garry
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martno1fan

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Re: 2.4 ghz radio / range / failsafe
« Reply #1 on: February 03, 2015, 11:08:20 AM »

Not just a case of 2.4 or not also check your using the fasst system not spectrum,spectrum hops between 2 channels only where as fasst hops 100 times a second so no chance of any signal issues under normal use.Ive never had my antenna external its allways stayed in the box,mine has two small 6" ones.2.4 gig will not penetrate water but its fine on water although spectrum isnt unless you use the specific marine rx and even then i dont trust it although many use it,futaba fasst for me although i have used the flysky radios with success,not sure what channel hoping they do havent looked into it.If you want problem free radio gear then the futaba fasst system is very good.
Mart
http://www.futaba-rc.com/technology/fasst.html
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flashtwo

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Re: 2.4 ghz radio / range / failsafe
« Reply #2 on: February 03, 2015, 11:12:22 AM »

Good job I keep my own record of my posts, since yesterdays replies have been lost - here is my post again..................

Hi,
For those that can remember VHF television (45MHz), when large aircraft flew in the area, the TV picture would fade and sometimes loose its synch signal and begin to role. For those with even longer memories will recall Radio Luxembourg (208) and pirate radio fading in and out terribly. Both were caused by multipath propagation where the radio signal would be reflected by the aircraft/ionosphere causing constructive and destructive interference.

 Single radio frequencies are prone to this multipath interference, but if the same information (in our case 1s and 0s) is sent over more than one frequency then the effects of fading can be reduced by reassembling the data from each of the “receivers”.

Now in the case of our 2.4GHz system, the radio band is divided up into 13 channels each with 5Mhz bandwidth. A very simple system would just use two frequencies within that 5MHz to represent either a 1 or a 0 resulting (you’ve guessed it) multipath interference.

With the modern (actually the military had it in the 1940/50s) “spread spectrum” technique, most of the 5MHz bandwidth is modulated and the information (1s and 0s) is spread over a lot of frequencies and is reassembled at the receiver.

There are different types of “spread spectrum” -  the Direct Sequence, where the original information is mixed with a Data Pattern known to the transmitter and receiver, and the Frequency Hopping type, where again the hopping information is known to the transmitter and receiver.

In both cases the Pattern and Hopping information is different between systems using the same frequency band and can reduce interference between them.
 
Apart from systems being on the same frequency, they can also select which of the thirteen 5MHz channels to use. They can do a survey of channel use and select the least busy to use. Some do it once others continuously (Futaba).

In our radio control systems, the Frequency hopping type (FHSS) is used since it is better at resisting pulse jamming (all those 1s and 0s) than the Direct Sequence type.

In summary the “Spread Spectrum” reduces fading and enables lots of users on the same frequency. What it can’t avoid is a very weak signal in the first place. Some systems have a receiver with two antennae at 90deg to each other to avoid loss of polarization (think of sunglasses) of the radio signal.

Regarding the use with submarines, that has, as you know, more to do with 2.4GHz not penetrating the water as well as the 40MHz.

I’ve tried to find out about the limits of the number of users, but no success, so far.

I got into this amount of detail because I’ve just used an XBee system (18 billion, billion unique addresses!) for a telemetering link to my Edwardian Steam Launch see

http://www.modelboatmayhem.co.uk/forum/index.php/topic,48575.25.html
and
http://www.modelboatmayhem.co.uk/forum/index.php/topic,37563.50.html

Ian
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craig dickson

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Re: 2.4 ghz radio / range / failsafe
« Reply #3 on: February 03, 2015, 07:55:59 PM »

Hi Mart, Ian and everyone


I found your replies very interesting thank you.


Mart, those I know that have used the Futaba Fasst system, absolutely swear by it so for me that speaks volumes. For my part I switched to using Hitec in its entirety for my boats that is, Transmitters, receivers and servos. The Hitec Optima 6 Sport features the AFHSS (Adaptive Frequency Hopping Spread Spectrum) technology, and it does it at a price that is within my budget. It gives a lot of features for relatively little money and I have never had a single problem when testing or racing boats with this combination. I guess that we rightly tend to stick with what we find works best for us. You were right to mention Mart, that it is not simply a question of thinking that "2.4gig solves all issues." because some of the very cheap 2.4 sets have very limited range regardless of application whether that be planes or boats.


Ian, thank you very much for your very interesting and informative reply. It is good of you to add input into this BMPRS power section of the forum and I much appreciate that. I have to say having clicked on your links I absolutely loved watching the you tube clips of your fabulous steam launch in action! :-))


Finally on the topic of Radio Control, the 2014 Winter Special edition of Model Boats, included a special feature "Radio Ga Ga!" by Dave Milbourn. I found that a fascinating read.


Cheers
Craig :-)


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spearfish99

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Re: 2.4 ghz radio / range / failsafe
« Reply #4 on: February 05, 2015, 12:41:42 AM »

For racing, I have Futaba FASST transmitters but find the Futaba receivers a bit expensive so use Orange or Frsky FASST rx's.  Not only do they seem as reliable as Futaba for a much lower price but also have advantages in terms of failsafe action.
 
With the Futaba TX/RX combinations you can only have one failsafe action, invariably on the throttle. With the Futaba Tx/Orange or Frsky Rx you can get far more. If you turn off the failsafe function on the Tx , the Rx can be set, with one press of a micro switch, to go failsafe on all 6 or 8 channels . You just place all the controls on the TX to where you want the failsafe position to be for each channel and then press the Rx micro switch. You can get a failsafe rudder, throttle gas engine kill switch whatever , all operating on loss of signal.
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martno1fan

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Re: 2.4 ghz radio / range / failsafe
« Reply #5 on: February 05, 2015, 08:14:39 AM »

Hi Ian which rx,s are you talking about do you have any links,your right about the price of the futaba rx,s,be nice to have some spares without the heavy price tag lol.That said i seem to use my cheap flysky radio more than the futaba as prefer it to the stick radios for ease of use as i normally boat alone so a pistol grip setup is much easier to work with.
Mart
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spearfish99

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Re: 2.4 ghz radio / range / failsafe
« Reply #6 on: February 05, 2015, 02:30:56 PM »

Hi Mart,
 here are a couple of links on Hobbyking. Also if you search FASST on Ebay, you should see some as well, although sometimes these are dearer than Hobbyking.
 
The Frsky rx I have been playing with is a TFR8 , not certain whether this is still a current model ( just checked, the current one is slightly different to mine).  They bind really easily and have plenty of range etc.  Corona also have some FASST rx's but I have seen comments that the servo resolution is not as good as the Orange/frsky ones and is a bit notchy.
 
At about £20 each, they have got to be worth a try.  I do have one of Futabas own 617 rx's and can see no appreciable advantage over the "cheapies" and you do lose out by only having one channel that you can get failsafe operating on.
 
On my set up for a Zenoah, I had a MrRC World kill switch set up on a switched channel. With the orange Rx, failsafe could be set to rudder hard over one way, throttle closed, kill switch operative, whereas on the Futaba I would have had to chose only one, probably the kill switch .
 
Unlike you, I am a confirmed two stick style box man, although I did think I might try one of the wheelie ones , as they are relatively cheap
 
http://www.hobbyking.com/hobbyking/store/__14300__OrangeRx_Futaba_FASST_Compatible_8Ch_2_4Ghz_Receiver.html
 
 
http://www.hobbyking.com/hobbyking/store/__19626__FrSky_TFR4_4ch_2_4Ghz_Surface_Air_Receiver_FASST_Compatible.
 
http://www.hobbyking.com/hobbyking/store/__23926__Corona_R14FA_2_4Ghz_Fasst_Compatible_Reciver.html

http://www.mr-rcworld.co.uk/index.php?productID=1030
 
Just as an aside to this, I just bought a cheapie off of Ebay ( late night finger again!) which is an upmarket Graupner MX-16 set which has been converted from 35mhz to 2.4ghz using one of the FrSky hack units and one of their ACCST receivers. Still playing with it. Interesting thing is that for £25 I have a set up which with an appropriate Rx will give telemetry, not that it was the purpose of buying the kit. Have ordered another of the hack units (£14) and intend trying to convert one of my old 40mhz sets. Only requires 3 wires soldering onto old Tx, and two of those are +ve  and -ve power supply
html
 
Regards
Ian
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ids987

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Re: 2.4 ghz radio / range / failsafe
« Reply #7 on: March 09, 2015, 12:05:42 PM »

Sorry, I know I'm a bit late to the party on this, but commenting, because it's an interesting subject.
If we were to do an apples to apples comparison of the frequency bands themselves (27MHz vs 40 MHz vs 2.4GHz), using the same equipment, and technology sets, 2.4GHz would lose hands down, and 27MHz would do slightly better than 40MHz. To make 2.4GHz useable, is entirely dependent on the technologies used.
The first problem with 2.4G is penetration. Apart from penetration (or lack of), through water, it has much less penetration through solid objects. Obstacles, including obstacles on the water, parts of the boat etc, will attenuate the 2.4G signal much more than 27MHz or 40MHz. This is one of the reasons for dual antennae. Personally, I would never use any 2.4GHz system without dual antennae, but that's not to say that any dual antenna system is necessarily good.
Secondly, multipath effects, as mentioned by Ian. This exists at all radio frequencies, but presents a specific problem here. Imagine that the radio signal has a sine format (hopefully most people remember what a sine curve looks like), with peaks and troughs. A reflected signal is delayed, compared to the main signal, which means that the peak of the reflected signal will arrive later than the peak of the direct signal. If this delay is such that the peak of the direct signal, arrives at the same time as the trough of the reflected signal, you have cancellation. If the peak and trough are exactly aligned, and of the same strength, you have full signal cancellation. On the other hand, you could receive the previous peak of the reflected signal, at the same time as the peak of the directly received signal, they reinforce each other in terms of strength, but the reflected signal is slightly delayed (going back to radio / TV analogies, in the world of analogue TV, the differently timed reflected signals, were the main cause of the often seen "ghosting" effect on the picture, but this is in the world of longer distance transmission, where the reflection could be travelling much further than the main signal. The delay in itself is not likely to be problematic in our environment, for several reasons). Between these extremes, are all the different potential degrees of signal alignment (direct vs reflected again). To put some of the above into context, at 40MHz, the wavelength is over 7M, which means that the distance between peak and trough is about 3.5M. At 2.4G, the wavelength is about 13cm, so the distance between peak and trough is only 6.5cm. This gives much more potential for problems (the relationship between direct and reflected signals will constantly change significantly as the model moves).
The second antenna can help a lot, both with the blocked signal scenario, and issues with signal cancellation from the reflected signal. Because of the nature of the signal, if one antenna is blocked, it's very possible that another, not too far away, will receive a useable signal. The same goes for cancellation. If the signal to one antenna is cancelled by a reflection, the signal to the other one may well be good. If the antennae are very close together, and in the same plane, these advantages are negated. In an ideal world, if we are trying to pick up a direct signal (rather than a reflected signal), the Tx and Rx antenna should be in the same plane, which is usually vertical. You can have both antennae vertical, but if you do, don't run them up the same tube, or have them right slap bang next to each other. Futaba show a setup where each antenna is 45 degrees to the vertical, in opposition, so that the antennae are at 90 degrees to each other. I believe this is intended primarily for aeroplanes, so that one is roughly vertical when climbing, and the other is roughly vertical when descending. In boats, some have one antenna vertical, and one horizontal. The horizontal antenna will never receive the best direct signal from a vertical TX antenna, and horizontal antennae are also somewhat directional (if a horizontal antenna is oriented along the boat, it won't work very well when it's coming towards, or going away from you, only going across), but reflections of radio signals also tend to scatter their polarisation, so one vertical and one horizontal often works ok in practise (also bear in mind that we are nowhere near to the distance limitations of the equipment, it is only the physical environment which we are trying to compensate for.
A by-product of frequency hopping, is that when the frequency hops, the wavelength also changes slightly, which shifts the cancellation modes / nodes a bit, so if a signal is fully cancelled before the frequency hops, it won't quite be afterwards. In practise, our models are moving quite fast, and movement is constantly shifting the relationships of direct and reflected signals.
I personally like the Futaba FASST equipment too, and have also found the FrSky FASST compatibles to be very good. I initially tried these, because I'd previously used the native FrSky system - after reading up on it, and used the FrSky hack module, to convert an old Futaba 35MHz Skysport set I had lying around, which worked very well.


Ian S
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Re: 2.4 ghz radio / range / failsafe
« Reply #8 on: March 09, 2015, 03:08:26 PM »

As an old man who has worked in communications all my life
on equipment transmitting on wave lengths from over a mile to 3cm
I think this last post is the best explanation for the guys who are
Trying to understand the 'black art'.
Well posted ids :-))

Ned
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Re: 2.4 ghz radio / range / failsafe
« Reply #9 on: March 09, 2015, 04:39:28 PM »

As an old man who has worked in communications all my life
on equipment transmitting on wave lengths from over a mile to 3cm
I think this last post is the best explanation for the guys who are
Trying to understand the 'black art'.
Well posted ids :-))

Ned


Thanks Ned !!
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craig dickson

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Re: 2.4 ghz radio / range / failsafe
« Reply #10 on: March 09, 2015, 07:35:12 PM »

As an old man who has worked in communications all my life
on equipment transmitting on wave lengths from over a mile to 3cm
I think this last post is the best explanation for the guys who are
Trying to understand the 'black art'.
Well posted ids :-))

Ned


I second what you said Ned!
A very informative and interesting contribution from Ian, and thank you for taking time out to share your knowledge Ian. :-))


Craig
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ids987

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Re: 2.4 ghz radio / range / failsafe
« Reply #11 on: March 10, 2015, 10:12:08 AM »

Hi all, Something I forgot to mention, which may be significant in some cases. I mentioned the reception pattern of the receive antennae, and the transmit antenna is of the same type. The tiny coax goes up the tube, and the last ~3cm is a small single pole antenna. The antenna radiates in a kind of doughnut pattern, with not much signal coming out of the end. If the antenna tube is straight, such that the end is pointing across the lake, when the transmitter is held normally, you will have the worst possible scenario, for signal strength on the water. To make it worse, because you're usually looking at the boat, you'd also be pointing the end of the antenna at the boat too - if you did this. I mention this, because I have seen it done. The stronger the signal is on the water, the better the chance it has of overcoming the challenges of the terrain.
I did set one boat up with horizontal antennae; one aligned along the boat, and one across. The Tx antenna is set horizontal, but parallel with the pits. This seems fine so far
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flashtwo

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Re: 2.4 ghz radio / range / failsafe
« Reply #12 on: March 10, 2015, 12:19:37 PM »

Hi,

The best analogy I heard from a lecturer many years ago regarding how an antenna works was the effect of stamping on a fire hose pipe - those canvas ones that lie flat.

With the ends shut off, stamping will cause a visible pressure wave to travel up the pipe and bounce (reflect) off the end and come back and if sufficient force has been applied, it will also reflect off the other end and you might even hear it "slap" and transmit audible energy - the energy has to go somewhere..

Stamping is the equivalent of "injecting" electrical energy (i.e. the sine wave) into an antenna and the slapping sound is the equivalent of transmitting electro-magnetic waves.

The length of the fire hose is critical if the reflections are to take place at either end - likewise with the antenna length it has to be a function of the frequency of the transmitter oscillator. The oscillator injects a quantity of energy then "switches off" to trap that energy in the antenna which gets rid of it in the form of the radio signal.

Ian
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ids987

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Re: 2.4 ghz radio / range / failsafe
« Reply #13 on: March 10, 2015, 02:53:01 PM »

Hi,

The best analogy I heard from a lecturer many years ago regarding how an antenna works was the effect of stamping on a fire hose pipe - those canvas ones that lie flat.

With the ends shut off, stamping will cause a visible pressure wave to travel up the pipe and bounce (reflect) off the end and come back and if sufficient force has been applied, it will also reflect off the other end and you might even hear it "slap" and transmit audible energy - the energy has to go somewhere..

Stamping is the equivalent of "injecting" electrical energy (i.e. the sine wave) into an antenna and the slapping sound is the equivalent of transmitting electro-magnetic waves.

The length of the fire hose is critical if the reflections are to take place at either end - likewise with the antenna length it has to be a function of the frequency of the transmitter oscillator. The oscillator injects a quantity of energy then "switches off" to trap that energy in the antenna which gets rid of it in the form of the radio signal.

Ian


If you apply this analogy to a (tuned) antenna, with decent SWR, and a transmitter driving it, you'd be stamping at regular intervals, and the length of the pipe would be such that the pressure wave would travel to one end, reflect to the other, and reflect back to the middle - just in time with the next stamp. This is an analogy of what's happening in a dipole, and a monopole is functionally similar, but the ground kind of acts as the other pole. If the reflection is out of time with the stamp (hose too long or too short), you have degraded SWR, and degraded efficiency.
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Re: 2.4 ghz radio / range / failsafe
« Reply #14 on: March 10, 2015, 02:55:32 PM »

Degraded SWR and the output stage stops playing <:( <:(

Ned
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Brigadair

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Re: 2.4 ghz radio / range / failsafe
« Reply #15 on: March 10, 2015, 07:59:31 PM »

Hi all


Thanks very much for the technical explanations given above.


I use futaba fass something or other 2.4 ghz. Keep the two areals in a horizontal plane within my radio boxes (no external areal), and both are taped to inside of radio box at 90'.


Not sure if this is any good, but so far seem to get a good reception? (Without failsafe being unwantenly operative!)


Have to say as a bit of a dim whit, I got lost in the fog of the electronic physics, but will read and re-read this interesting thread a few times before I add more!!


Cheers for now.


Garry



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Re: 2.4 ghz radio / range / failsafe
« Reply #16 on: March 10, 2015, 08:38:40 PM »

Hi Folks


Fascinating stuff in not above my head in terms of the technical details O0
And again thank you to those that have shared such detailed technical explanations.


Should I be worried though having switched to the Hitec Optic 6 system over a year ago? My Optima receiver only has one single antenna, fairly long which I route around the side and transom of the hull. Their instruction manual says that their Boosted Omni Directional Antenna matches or betters the dual antenna systems of their competitors. ;D 


For me personally with the Hitec Optic 6  system I have not had a single issue with it. Because it has delivered faultlessly over many BMPRS race events.


In my opinion, which ever radio set you opt for, I  think it is important to do the range tests and be comfortable that your set does deliver when racing the boats.


In model power boating terms, from my experience one of the most common causes of radio control problems is not the limitations of modern sets, it is water ingress into the radio box.


I will open a separate topic on this shortly.


Cheers
Craig
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ids987

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Re: 2.4 ghz radio / range / failsafe
« Reply #17 on: March 10, 2015, 11:12:27 PM »

Hi Garry, that horizontal setup sounds much like I was describing earlier. Not quite as good as having the Rx antennae out of the boat, in free space, but a good compromise, and good enough, I'm sure. For best results, the Tx antenna should be horizontal as well, across your body - not pointing out across the water.

To Craig, your setup is well tried and tested, so I guess that speaks for itself. Range checks are less meaningful with 2.4G, but still worthwhile - if only to check that the equipment is working as it should. Apart from the electronics, the antennae are quite fragile, both the wire itself, and the connections.
Water ingress, yes. All my comments were on the basis that all equipment was in full working order. To add to that, most of the complete "out if control" incidents I've seen, have been caused by sudden loss of power. Broken power wire (often due to corrosion, caused by historic water ingress), corroded connectors, switches etc.

To Ned, yes, the dreaded (usually expensive) flash, ping.
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Re: 2.4 ghz radio / range / failsafe
« Reply #18 on: March 11, 2015, 08:36:45 AM »

Both my antennas are inside my radio box which is water tight,zero problems so far in 5-6years of using the fasst system.Used that setup in both a wooden hydro traveling at close to 70 mph and inside my Apaches,not so much as a glitch it works perfectly.So im with dim whit Garry on this one  :} .
Mart
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Re: 2.4 ghz radio / range / failsafe
« Reply #19 on: March 11, 2015, 11:30:25 AM »

Both my antennas are inside my radio box which is water tight,zero problems so far in 5-6years of using the fasst system.Used that setup in both a wooden hydro traveling at close to 70 mph and inside my Apaches,not so much as a glitch it works perfectly.So im with dim whit Garry on this one  :} .
Mart


I'm going this way again, for a build I'm just finishing, and I'm confident it will be ok. It's amazing what the better 2.4G kit will allow you to get away with, installation wise. The fact that we're using it over such a short range obviously helps, but it's only part of the picture.


Their instruction manual says that their Boosted Omni Directional Antenna matches or betters the dual antenna systems of their competitors. ;D   



Trying to find out some info on this Craig. I think I have a rough idea what they've done. It's still only the end section which is the actual antenna, but the antenna section is longer than the others are using. I believe the antenna starts at the larger diameter of the shrink wrap, and ends at the tip. It's probably a bit more efficient than most, which just have the sheath of the coax removed for the last 3cm.


Like the antennae used by the others, I'm pretty sure it will only be truly omni directional around the antenna part - not off the end (meaning it would only be truly omni directional if mounted with the actual antenna vertical). I notice they also produce some receivers with two of these BODAs, for dual antenna diversity - like FASST, FrSky etc. It seems to be working well in practise though, for you, and others.


Ian
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Re: 2.4 ghz radio / range / failsafe
« Reply #20 on: March 11, 2015, 05:02:50 PM »

For best results, the Tx antenna should be horizontal as well, across your body - not pointing out across the water.


Hi Ian


The above caught my attention, only because I have always had my Tx antenna pointing vertically upward thinking that was the best option.
So with my single RX aerial horizontal in the radio box presumably I should get into the habit of doing as you advise.


Thank you for your further helpful contributions.


Cheers
Craig
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Re: 2.4 ghz radio / range / failsafe
« Reply #21 on: March 11, 2015, 05:36:59 PM »

Hi Craig, If the antenna is pointing up in the air, then you have good omnidirectional coverage in the horizontal plane. It will radiate in a circle (a bit like a doughnut pattern) about the antenna. This is good, but works best if the receive antenna is also vertical. If one is vertical, the other should ideally be vertical. The ideal is always line of sight from Tx antenna to Rx antenna, with nothing in the way, and with Tx and Rx antenna parallel with each other. This ideal can only happen if the antennae are vertical, and above the boat and surrounding obstacles (or a hypothetical straight line between the two antennae passes above solid objects). Thankfully our equipment will work, over the sort of range we use, with something which falls way below optimal, but I think it's good to improve the areas you easily can, because we don't really know how good or bad reception was, unless it drops out; in which case it was really bad.
Similarly, if the Tx antenna is horizontal, the Rx antenna should ideally be horizontal, but this brings further layers of complexity. As mentioned, the signal coming off the end is relatively weak, so pointing the end at the boat is the worst possible scenario. You really need it to be horizontal across your body, so that the dead spot is beside you, and you're still radiating a decent signal forwards.
The same applies to the receive antenna pattern, when you only have one antenna in the boat. It's least sensitive end on, but we're usually positioned somewhere in the middle of a straight, so it's unlikely to be pointing straight at, or straight away from you.
Also, if the antenna is inside the boat, probably much of what it's receiving is reflected, which means the polarisation will be scattered, so it's harder to predict.
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ids987

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Re: 2.4 ghz radio / range / failsafe
« Reply #22 on: March 12, 2015, 10:22:34 PM »

Sorry. Me again. I got to thinking again about the question of sporadic failsafeing - assuming that's what happened in some of these cases.
Generally, there's a timeout before failsafeing. You have to lose signal for a fairly significant period of time, before the failsafe kicks in. Assuming the equipment is all working normally, the boat has previously made some uninterrupted laps, and it's not a recurring issue with the same boat. I got to wondering what is big enough to potentially block the line of sight, and could potentially do so for long enough. I wonder if the rescue boat and / or crew may have been in the Tx->Rx line of sight in some cases; especially since some of the rescue boats are metal.
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martno1fan

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Re: 2.4 ghz radio / range / failsafe
« Reply #23 on: March 14, 2015, 11:50:26 AM »

Ahh so going by your thinking about large objects blocking the signal Ian it mght be an ideo to keep Mark out of the rescue boat lol  :} ,alright Mark  ;D .
Mart
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tmbc

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Re: 2.4 ghz radio / range / failsafe
« Reply #24 on: March 15, 2015, 10:45:45 AM »

i only do rescue boat when digger is racing so i can make sure he wins ! youve let my secret weapon out now "oh dam" will just have to resort to standing infront of every one else from now on lol

 
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