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Doc Marten28/02/2019 10:23:14
432 forum posts
5 photos

Good morning all,

I have a module based Futaba on 35mHz but would like to try out 2.4 mHz using my Tx, I'm drawn to the FrSky modules so I can use the FrSky range of Rx, I've been told that LBT is what I need but I can't find a Futaba module from FrSky that is LBT, only JR.

I understand that LBT is a response to new regulation from the EU, introduced from 2015 and that new gear must conform to it, have I got this right?

What is D, LR and V mode?

ATM I have no need for telemetry as I am IC.

Could the collective wisdom shed some light on this 2.4 clueless soul?

Thanks

Marten

G194028/02/2019 14:38:55
3523 forum posts
1 photos

I started with FrSky by using a plug-in module on my old Futaba FF7 Super (not the later FF7). It worked well but it wasn't LBT (Look Before Transmit) as IIRC that wasn't in force at the time. In fact, even after the LBT rules were introduced I always used International standard receivers and re programmed any receivers with LBT to the other standard - eventually I bit the bullet and converted my old receivers to the LBT configuration.

The JR refers to the physical configuration of the plug-in module (ie pin allocation and the shape/size of the box. All Frsky transmitters use the JR module standard and that's why a lot of modules specify it. It was some time since I used my FF7/Frsky module (I sold it a couple of years ago) and I'm not sure if Frsky still manufacture a Futaba compatible plug-in. If they do, that's obviously the one to buy.

Telemetry is still useful even if you fly IC powered models. At least it will give you an early warning if the received signal strength is becoming low or critical.

I eventually moved over to Frsky 100% with first a Taranis and now a Horus.

Geoff

Frank Skilbeck28/02/2019 15:16:35
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4610 forum posts
101 photos

Marten, have you spoken with T9 Hobbysport the UK authorised representative for Frsky, they have Futaba modules for sale on their webpage, if they are selling them for use in the UK they must be LBT.

Peter Christy28/02/2019 15:19:45
1729 forum posts

As far as I'm aware, the only Futaba compatible FrSky module is the DFT module, which only does the D & V protocols.

To clarify: "V" was FrSky's original 2.4 GHz system and is non-telemetry. "D" was their first telemetry capable protocol. It delivers a rock solid link, but does not conform to the latest LBT (Listen Before Transmitting) EU requirements - however, there is a caveat here which I'll come to later....

The current FrSky system is the "X" protocol, which is available in either EU (LBT) or "international" (non-LBT - as used in the rest of the world) versions.

Any transmitters that "entered the supply chain" (to use the EU's legalise) after January 2015 must conform to the EU standard. However, your Futaba transmitter presumably pre-dates this requirement, and can therefore use a DFT (non-LBT) module.

Its a legal "grey area", but I wouldn't worry about it. No-one else seems to. I've got quite a few old transmitters that I've updated using FrSky DFT and hack modules. I've never been queried at any event I've been to!

The FrSky "D" series receivers are legal, as they are using less than the specified media useage factor, so they don't need to be LBT for telemetry. And all the X-series receivers I've bought can be made to drop back to "D" protocol by jumpering a couple of pins during the bind process. So there is no fear of receivers becoming unavailable.

The "D" series telemetry is not as sophisticated as the latest "X" series, but its quite adequate, and will return the airborne voltage and received signal strength to the ground. With a module, you just get warning beeps instead of a display on the transmitter, but you can get an extra panel to attach to your Tx that will give you read-outs if you want it.

To summarise: For Futaba, you appear to be stuck with the older "D" protocol. However, it is rock solid, and provides a reasonable amount of information back via telemetry. It is possibly a legal grey area, but I've never heard of it causing a problem anywhere. Certainly I've never had my equipment challenged.

Go for it! wink

--

Pete

Andy Meade28/02/2019 15:26:24
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2749 forum posts
709 photos
  • You won't find a modern FRsky module to fit a Futaba tx I believe. The nearest you'll get is a DFT I think (the F stands for futaba). Then you'll need an external screen to show telemetry values. I'm not sure, but I dont think the DFT modules can talk to the later, better range of receivers ("X" and "S" series).
  • Telemetry can also give you your RX battery levels of course, which is a very common failure point of RC aircraft.
  • You can use LBT, I use the non-EU firmware in all of my FRSky gear, rightly or wrongly. I did it that way round as I had a lot of receivers that I couldn't be bothered to update when the law changed. Note that T9 sell outside the EU too - they stock both types.
  • D and V modes suit older types of receiver, LR is long range 2.4ghz and I believe doesn't use telemetry at all.

Ah, Looks like we've crossed over Pete

Edited By Andy Meade on 28/02/2019 15:26:48

J D 828/02/2019 16:48:16
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1392 forum posts
79 photos

Off at a tangent here. I think he just wants to convert his present Futaba TX to 2.4.

Doc Marten28/02/2019 16:56:51
432 forum posts
5 photos

Thank you all, just as I think I'm beginning to understand it I receive an email from T9 Hobbysport confirming that there is no Futuba LBT module from FrSky and that the DFT module works with the non telemtry V8 Rx, no mention of the D mode.

Still confused.

Doc Marten28/02/2019 17:00:47
432 forum posts
5 photos
Posted by J D 8 on 28/02/2019 16:48:16:

Off at a tangent here. I think he just wants to convert his present Futaba TX to 2.4.

Yes but using FrSky and to be educated in 2.4mHz.

Frank Skilbeck28/02/2019 17:01:29
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4610 forum posts
101 photos

Marten, I think you have missed the boat as far as 2.4 modules go, when 2.4 first came out there were lots of modules (from various manufacturers) to allow 35 mhz Txs to be updated, but now most fliers have either converted their Txs or got new 2.4 ghz ones. Sounds like it's time for a Tx upgrade.

Doc Marten28/02/2019 17:13:04
432 forum posts
5 photos

If I were to upgrade to a LBT Tx, would I still be able to use the D and V modes or would I be tied into x mode only?

Simon Chaddock28/02/2019 18:04:43
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5621 forum posts
2987 photos

Doc Marten

As others have suggested it is probably best to buy a new modern 2.4 Tx and receiver9s). It is by far the simplest route.

You can always do as i have done and keep the 35 meg for on some planes and 2.4 for others.

All you need to do is to decide which 'system' but don't to ask which is "best". You will get as many different suggestions as you get answers! Try to find a reason why one is preferable to you over any other.wink 2

gangster28/02/2019 18:13:45
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999 forum posts
17 photos

There have been a lot of confusing posts here. Let’s simplify this. I assume you want to use a good faithful old Futana TX on 2.4. To be honest an older TX with an frisky module will probably result in a far better system than you can buy today. So surely the simple answer would be to ring T9 get a dft module and ask th which receiver will work with it and buy a few of them. Shouldn’t worry about let. T9 will only have current spec stuff. The rules changed 4 years ago and anyway did not affect what we use just what the manufacturers supply. I use a sky module in an old JR with v8fr receivers I am am sure those modules support 2 of the modes but T9 will know

Edited By gangster on 28/02/2019 18:14:50

Martin Harris28/02/2019 18:32:05
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9172 forum posts
242 photos
Posted by Doc Marten on 28/02/2019 10:23:14:

ATM I have no need for telemetry as I am IC.

It probably saved my Chipmunk way back in around 2010 when a cell died in its receiver pack.

Peter Christy28/02/2019 19:20:09
1729 forum posts

If you go to the T9 page for the DFT module:

**LINK**

you will see documents to download with all the details. The "modules" document will confirm that the DFT module does work with "D" series telemetry receivers.

--

Pete

Doc Marten28/02/2019 19:25:56
432 forum posts
5 photos
Posted by gangster on 28/02/2019 18:13:45:

There have been a lot of confusing posts here. Let’s simplify this. I assume you want to use a good faithful old Futana TX on 2.4. To be honest an older TX with an frisky module will probably result in a far better system than you can buy today. So surely the simple answer would be to ring T9 get a dft module and ask th which receiver will work with it and buy a few of them. Shouldn’t worry about let. T9 will only have current spec stuff. The rules changed 4 years ago and anyway did not affect what we use just what the manufacturers supply. I use a sky module in an old JR with v8fr receivers I am am sure those modules support 2 of the modes but T9 will know

Edited By gangster on 28/02/2019 18:14:50

T9 advise that for the Futaba, these are the Rx that will work with the DFT module:

**LINK**

They are non telemetry, how would I get get a telemetry option?

If I were to buy a new 2.4 Tx (the Taranis QX7S is appealing), would it be supplied in LBT format only? Would I then be tied into LBT or could I still use non EU telemetry gear? Do I lose out by not being able to use X mode Rx?

Thanks for bearing with me guys, this is all appreciated and very interesting.

Edited By Doc Marten on 28/02/2019 19:27:03

John Muir28/02/2019 20:39:22
377 forum posts
1 photos

The DFT module is exactly the same inside as the DJT module and I can assure you, from personal experience, that it works with V8, D8 and 'X' series receivers as long as they can be bound in D8 mode (it will say in the product description). I used one with all of these and it worked perfectly. I went for X8R LBT receivers latterly to 'future proof' myself and eventually bought a Taranis QX7 LBT version which, when loaded with the correct version of its firmware, also operates all of these receivers while making all the telemetry features of the more recent ones available.

A word of warning though, if you want to keep things simple just get the module and some receivers, plug it in and get flying. The FRSky protocol is excellent but their transmitters are not everybody's cup of tea and it takes some work to get the best out of them. Do some internet searching and some reading before going down the Taranis path as one or two people have found themselves a bit bamboozled and ultimately disappointed. Personally I love my Taranis and wouldn't have anything else, but it isn't for anyone who doesn't like computers and tinkering around with stuff to see how it works.

Doc Marten01/03/2019 08:15:15
432 forum posts
5 photos

Thank you to all who offered advice, based on that and my own feelings I have ordered the DFT module and the last D8R II plus receiver from T9. Will LBT be a consideration after Brexit?

Thanks again for your help.

gangster01/03/2019 08:35:45
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999 forum posts
17 photos

Not sure if lbt is an issue at all as far as we,the end user is concerned. The reputable supplier supplies whatever the regulations demand and we buy it and use it. Nothing we use for flying has been made obsolete by change of regulations A few scare mongers get hung up about such things but let’s face it our radio is a consumer item to control a toy aeroplane. Also the DFT module will bind in at least 2 of the frsky modes.

Doc Marten01/03/2019 08:41:51
432 forum posts
5 photos

So what is the real reluctance towards LBT? I'm under the impression that it ties you in to a protocol with reduced range? Am I being mislead?

Peter Christy01/03/2019 08:45:12
1729 forum posts

Ofcom seem to take a much more relaxed attitude to specification than the old PO used to. A few years ago, they told me that they would almost certainly agree to spread spectrum on 459 MHz if we asked.

I suspect that, post Brexit, if someone like the BMFA were to ask for the EU LBT restrictions to be relaxed, they would at least consider it.

--

Pete

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