Barry Spiers Posted February 11, 2015 Share Posted February 11, 2015 hi guys, wonder if someone could point me in the right direction..... I'm build a Skywalker FPV 1900 and initially I will fly with the x8r RX, Eagletree vector etc. I have seen a few youtube vids of people getting really good distances with the Taranis db5 antenna mod combined with extended FrSky RX antenna. Could anyone confirm this is a worthwhile Taranis mod and if so, where I can buy the antenna mod in the UK, I've managed to find the RX exteded antenna but can't seem to find the 5db antenna mod for Taranis..... Any help and/or advice would be very welcome, Thanks, Barry Quote Link to comment Share on other sites More sharing options...
Martyn K Posted February 11, 2015 Share Posted February 11, 2015 5dB aerial gain will give you about 3.5x range gain - providing the aerial is pointing in the right direction. The gain comes at the expense of loss of an (almost) omnidirectional radiation pattern - ie a radiation pattern that transmits equally in all directions*. This means that you could be controlling a model at perhaps 4km distance but a slight movement of the transmitter and you could lose the signal completely. I don't know where to get the aerial from, but personally, I would stay well clear Martyn * For the pedantic - its not truly omnidirectional - more of a carotid or doughnut shaped radiation pattern with almost nothing being transmitted along the direction of the axis of the aerial Quote Link to comment Share on other sites More sharing options...
Chris Jones 7 Posted February 11, 2015 Share Posted February 11, 2015 I've done the mod and it's very worthwhile but not for the reason of range etc. the advantage lies in that the 2dbi antenna is now removable/ replaceable depending on how clumsy you are this can be a real boon as a replacement is around £2. As for the 5dbi, I can't comment as I've not been brave enough to try it for the very reasons stated above. BoltRC UK shop has everything you need. Quote Link to comment Share on other sites More sharing options...
GONZO Posted February 11, 2015 Share Posted February 11, 2015 Here you go:- **LINK** **LINK** **LINK** Once converted to a screw fitting you could also use the 7dB patch. But, you would have to be sure it was always pointing at the plane. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 Have you considered the legality of this sort of mod? Most transmitters are fairly close to the maximum RF output as supplied. Edited By Martin Harris on 11/02/2015 18:16:33 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 11, 2015 Share Posted February 11, 2015 How great a range do you want? The legal limit is 500m - surely the standard equipment can easily give you that? If fly beyond 500m you are breaking the law. BEB Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 Not that I'm planning on flying that far away, but I have to admit not having seen any figure published - which legislation is it from (FPV perhaps)? Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 11, 2015 Share Posted February 11, 2015 The CAA define VLOS (visual line of sight) as 500m radius and 400ft altitude Martin BEB Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 Does that apply to general flying or is it something pertaining to commercial "drone" flying? The vast majority of thermal soarers would not comply with that height limit on a very regular basis! Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 11, 2015 Share Posted February 11, 2015 Its laid out in CAP722 Section 5 which relates to "civil operation of unmanned aircraft systems". CAP722 is of course "guidance" - in other words it is a strong pointer to how the CAA will interpret the rather vague requirements of the legislation - ie the ANO. While I doubt very much that they would apply this to say thermal soarer over deserted countryside - I'm certain they would invoke it as the definition of VLOS for an FPV flight - commercial or otherwise. BEB Edited By Biggles' Elder Brother - Moderator on 11/02/2015 18:51:47 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 That guidance is aimed at UAS operation BEB - not model flying. CAP 658 (Model Aircraft: A Guide to Safe Flying) makes no mention of a specific VLOS distance. Whether the average pilot of a small model at 500m is able to control his model safely so as not to endanger anyone is possibly debatable but I don't believe any specific offence would be committed by flying 501m from the pilot! I'm not taking issue with the sentiments - simply the statement that the pilot would be breaking the law... ...although I've just re-read the OP and realised that the question was posed by an FPV flyer so that may put a different complexion on things! Reference to the 2014 CAA exemption for FPV only reveals the following which seems to leave flight distance to the discretion of the operator: 3) a) The person in charge is the person piloting the SUA (see Note 2). b) The person in charge is accompanied by a competent observer who maintains direct unaided visual contact with the SUA sufficient to monitor its flight path in relation to other aircraft, persons, vehicles, vessels and structures for the purpose of avoiding collisions and advises the person in charge accordingly. and This does not remove the requirement (in paragraph 3(b)) for the competent observer to maintain direct unaided visual contact with the SUA throughout the flight. Therefore, the SUA can only be flown up to 1,000ft if it can still be seen sufficiently for collision avoidance purposes. Edited By Martin Harris on 11/02/2015 19:28:41 Quote Link to comment Share on other sites More sharing options...
Barry Spiers Posted February 11, 2015 Author Share Posted February 11, 2015 Many thanks for the replies guys, appreciate it, although I still can't find a place in the uk to buy the mod, no problem I'll get there. BEB thank you for informing me of the regulations although I am aware of them! Why you would want to question why I want to buy something is beyond me..... Barry Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 I suspect that BEB was too polite to ask if you were intending to operate beyond normal visual range! Quote Link to comment Share on other sites More sharing options...
Alan Jarvis Posted February 11, 2015 Share Posted February 11, 2015 If you add that 5db aerial you will almost certainly be breaking the law. Radiotelecommunications. The legal limit for power output on 2.4 Ghz is 100mw. The Taranis for the EU market will almost certainly be close to that. If you add a 5db aerial in perfect conditions you would increase the power by a factor of just under 4. The potential is for a power output of 400mw but of course there are other factors to consider too complex to discus here. Not only would it be illegal but could have a serious effect on other nearby equipment. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 11, 2015 Share Posted February 11, 2015 The law requires VLOS (unaided) - so if it all goes wrong and the CAA suspect the FPV pilot of being outside VLOS what definition are they likely to cite? I think you will find that it will be the one published and publicly available in the guidance - ie 500m. It is true that the guidance goes on to say that there may be exceptions if the aircraft is sufficiently large that the pilot/observer can maintain orientation and direction - that may be the case here but I doubt it. BEB Quote Link to comment Share on other sites More sharing options...
Pete B Posted February 11, 2015 Share Posted February 11, 2015 Posted by Barry Spiers on 11/02/2015 19:29:34: BEB thank you for informing me of the regulations although I am aware of them! Why you would want to question why I want to buy something is beyond me..... I have seen a few youtube vids of people getting really good distances with the Taranis db5 antenna mod combined with extended FrSky RX antenna. Given that a standard Tx-Rx combo has a range far exceeding the VLOS of a flyer or competent observer, it's not difficult to infer that you may be considering flying beyond that distance, so I'm not surprised the question was asked..... If the inference is correct, then this forum may not be the place to ask.... Pete Quote Link to comment Share on other sites More sharing options...
Barry Spiers Posted February 11, 2015 Author Share Posted February 11, 2015 Posted by Alan Jarvis on 11/02/2015 19:42:39: If you add that 5db aerial you will almost certainly be breaking the law. Radiotelecommunications. The legal limit for power output on 2.4 Ghz is 100mw. The Taranis for the EU market will almost certainly be close to that. If you add a 5db aerial in perfect conditions you would increase the power by a factor of just under 4. The potential is for a power output of 400mw but of course there are other factors to consider too complex to discus here. Not only would it be illegal but could have a serious effect on other nearby equipment. I am not saying you are wrong per say, however, have a read of this from FPVUK, go down to how do we increase range. http://www.fpvuk.org/things-explained/vtx-power-and-range/ Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 I've had a quick read of that, Barry and it specifically warns against any mods to increase transmitter power - it recommends increasing the receiver sensitivity. In fact, the article is about video transmission anyway! Edited By Martin Harris on 11/02/2015 20:15:00 Quote Link to comment Share on other sites More sharing options...
Barry Spiers Posted February 11, 2015 Author Share Posted February 11, 2015 Posted by Pete B - Moderator on 11/02/2015 19:51:40: Posted by Barry Spiers on 11/02/2015 19:29:34: BEB thank you for informing me of the regulations although I am aware of them! Why you would want to question why I want to buy something is beyond me..... I have seen a few youtube vids of people getting really good distances with the Taranis db5 antenna mod combined with extended FrSky RX antenna. Given that a standard Tx-Rx combo has a range far exceeding the VLOS of a flyer or competent observer, it's not difficult to infer that you may be considering flying beyond that distance, so I'm not surprised the question was asked..... If the inference is correct, then this forum may not be the place to ask.... Pete Actually Pete, your assumption or inference is wrong, at no time have I stated that 'I' wanted to fly long range, I simply want a little redundancy I my system to enable me to recover if something did go wrong. I guess I've struck a nerve mentioning the dreaded fpv word, I was not aware fpv was so frowned upon on this forum, apologies if I offended anyone by mentioning the F** word. Barry Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted February 11, 2015 Share Posted February 11, 2015 Barry Read what Martin wrote again (quoted below) and you will see that you are not adding a "little redundancy", instead you are introducing a potential loss of range due to the changed radiation pattern. I think you should consider carefully the implications of making any changes to your transmitting equipment and unless you can be totally satisfied that you know you are going to both be within the law and not compromise your systems reliability then don't change it! Posted by Martyn K on 11/02/2015 17:21:43: 5dB aerial gain will give you about 3.5x range gain - providing the aerial is pointing in the right direction. The gain comes at the expense of loss of an (almost) omnidirectional radiation pattern - ie a radiation pattern that transmits equally in all directions*. This means that you could be controlling a model at perhaps 4km distance but a slight movement of the transmitter and you could lose the signal completely. I don't know where to get the aerial from, but personally, I would stay well clear Martyn * For the pedantic - its not truly omnidirectional - more of a carotid or doughnut shaped radiation pattern with almost nothing being transmitted along the direction of the axis of the aerial Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 11, 2015 Share Posted February 11, 2015 I guess I've struck a nerve mentioning the dreaded fpv word, I was not aware fpv was so frowned upon on this forum, apologies if I offended anyone by mentioning the F** word. Barry Not at all, Barry - but we are cautious about any advice which might lead - even inadvertently - to model pilots operating illegally, which of course can hazard other models and possibly bring the hobby into disrepute. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 11, 2015 Share Posted February 11, 2015 Barry, I think you invoking preconceived stereotypes that are common in some FPV flyers and displaying a certain oversensitivity. There is no anti-FPV bias - Like some others on here I fly FPV, I fly a lot of multi-rotors as well - both manually and waypoint. I also fly "conventional RC aircraft. I don't believe what is being said here is not motivated by bias - its motivated to try to keep to the rules! BEB Quote Link to comment Share on other sites More sharing options...
Pete B Posted February 11, 2015 Share Posted February 11, 2015 Nothing wrong with FPV, Barry. However, with a first post containing the phrase 'really good distances with the Taranis db5 antenna mod combined with extended FrSky RX antenna', it's not unreasonable, in my opinion, to assume that the modeller is seeking to fly well beyond the range of the average Tx. Let's say that's a mile or so. At that distance the model will already be way beyond the distance the competent observer will be able to fulfill his responsibilies, that of direct unaided visual contact and the ability to take over control if necessary. Why would you feel the need to increase the range beyond that? Pete Quote Link to comment Share on other sites More sharing options...
Phil Green Posted February 11, 2015 Share Posted February 11, 2015 Posted by Barry Spiers on 11/02/2015 16:41:08: Any help and/or advice would be very welcome, except help and/or advice that you dont like, of course. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted February 11, 2015 Share Posted February 11, 2015 I'd suggest that a change of antenna is a bad idea, for all the reasons mentioned above, and the fact that you'd have to solder a very tiny coax connection. If you need more range, FrSky have a Long range Rx - the L9R - advertised as having approx twice the range of a standard receiver. If it's diversity you want, Rx diversity can simply be added by binding a second receiver. Full RF diversity can be arranged by fitting a Tx module into the back of the Taranis. There are a number of ways to deal with the output of two receivers. Quote Link to comment Share on other sites More sharing options...
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