Taranis 6 dbi Antenna Modification -

[HilldaFlyer]

Taranis 5 db Antenna Modification -

I started this thread to discuss if anyone has done the 5 db WiFi Antenna modification and what is your experience...

I just published this article on the modification to my Taranis:

In the article I cite 3 individuals who have performed the modification publicly:
IBCrazy, Mr. Steele and Joshua Bardwell

IBCrazy showed how to perform the modification, Mr. Steele did a range test showing the range was enhanced and Joshua had a bad experience - his Taranis stopped working. He also stated that many others had commented on this mod "breaking" their Taranises (or is it Tarani?)

I wanted to get some feedback from the community, especially if you made the modification and what is your experience. If anyone is buddies with IBCrazy, Mr Steele or Joshua, pass this onto them so they can comment. I'd really like to know.

 

[HilldaFlyer]

I've had a great experience. I put the RP-SMA connector on my Taranis about a year ago and it is working fine. I didn't do a range test before, so doing one now will probably not be useful and I'm not going to buy a new Taranis just to establish a baseline. I may have to find a friend that has one and do a little experiment.

There were a few people who posted in comment section of Joshua's YouTube channel indicating that the coaxial cable Joshua used was not cut to the specified length. I don't know if this damaged his radio. Do you know?

 

[PsyBorg]

Like any other internet fads I always wait to let others break their stuff before trying. I am glad I did.

Electrically the thoughts and process for it are sound. Heavier antenna feed, better shielding, better antenna. However.. you have to think it thru.. MOST (not all) of these mods are being done by people without electrical engineering degrees nor the schematics or parameters of what they are modding. Educated guess's can be alright as long as the principles of what they are working with are applied in the process. You can't just say oh if I put in thicker wire I will have better transmission and better shielding without taking into account things like impedance matching specially when it comes to rf transmission.

I know IBcrazy knows his stuff when it comes to antennas so I would trust his efforts. Steele has electrical knowledge as well as his fathers electrical background to draw from so that's a trusted resource. I have no idea of what Joshua's background is so it may be it is not as good so when he did his mods the precision and tools needed to match the transmitter properly to the antenna may not have been put in place or not done as well as it should have. I kind of have to believe that the ones who have had the mod work were careful and precise in following the proven method for the mod and that the others who have had failures not so much. Doing mod's just to keep up with the jones's is a gamer thing where people will do things JUST because others have done it regardless of consequences usually in the younger generations.

So yes if you have the skill, desire to take a risk, and most importantly CAN FOLLOW INSTRUCTIONS and SPECIFICATIONS rock on if you wish to do PROVEN mods. If you can not however I would advise not to do any mods like this and I won't feel sorry if you chose to do something you know you don't have the skills for and end up in a bad way. COMMON SENSE!!!

 

[makattack]

I'd actually be curious if there are any performance differences between a DIY modded TX and the newer "Special Edition" version that has a SMA connector using identical removable antennas.

http://www.frsky-rc.com/media/mediaItem.php?m_id=57

The most worthwhile (errr... only) upgrade I've done on my X9D+ is the M9 hall effect gimbals. It has changed my multirotor flying abilities. It's also sort of less dramatically changed how I fly fixed wings, but still for the better. My throttle use is just so much better in fixed wing since I adjusted the M9 gimbals to not use the ratcheted friction bar that my old gimbals had turned up and I never bothered to change.

 

[HilldaFlyer]

Like any other internet fads I always wait to let others break their stuff before trying. I am glad I did.

Thanks PsyBorg. I appreciate your comment. I feel the same way... so why did I do it? It was part of a greater (stupid) plan that has yet to come to fruition. I was going to use my Taranis as a ground station (master) stick it on a pole and use my Spektrum (wireless buddy box) to actually fly. I don't know if that is such a good idea now or if that would have increased the range (but I don't need it).

I also thought about putting on a long coax to the top of a pole where the antenna would be mounted. The thought was to get the working part of the antenna up higher. Again... lack of knowledge can be disastrous. I think I've talked myself down from both of those ledges... but I still have the RP-SMA jack on the Taranis.

 

[HilldaFlyer]

I'd actually be curious if there are any performance differences between a DIY modded TX and the newer "Special Edition" version that has a SMA connector using identical removable antennas.

http://www.frsky-rc.com/media/mediaItem.php?m_id=57

Yeah, that is a great idea! You buy the new one and we'll go testing it! I can meet you half way.

 

[HilldaFlyer]

Just found these additional references:

Post Publishing Notes:
Here are a couple more references:
NJ Teck

Expressive Imagery changed the length of a previous modification that improved his SWR.

http://boltrc.com/blog/taranis-antenna-upgrade-part-3-initial-results/

http://openrcforums.com/forum/viewtopic.php?t=8563

 

[PsyBorg]

There are also other considerations I took into account in my decision to not do the range mod. As with the goggles and FPV transmitter power these radios are designed to be within a certain radiated power out put. By doing the mod you have effectively changed that and more then likely taken the radio out of that spec range thus creating a potential problem with the F.C.C. as well as HAM regulations because of the band they are in.

The SWR video is relevant to what we are discussing. The higher the SWR the more energy is being fed back to the transmitter and not radiating out the antenna. This is most likely the reason people are frying their tx units and the major cause for that is a bad impedance match. From what I see of the mod that people do most of it boils down to how precise they make the new wire they replace. I don't think whomever did the initial mod took into account the added resistance of a heavy solder joint or the thick metal SMA connector. My guess is they only did the math for the wave length to figure out how long the wire is.

Btw I was not faulting you for doing the mod. I fully get the reasoning. I am fairly sure you have done your share of soldering and wire making in the hobby over the years and are quite capable to do the mod properly. The statement about waiting while others break their stuff is a general statement and mainly directed at younger more impatient people who must have the biggest and bestest everything.

 

[HilldaFlyer]

There are also other considerations I took into account in my decision to not do the range mod. As with the goggles and FPV transmitter power these radios are designed to be within a certain radiated power out put. By doing the mod you have effectively changed that and more then likely taken the radio out of that spec range thus creating a potential problem with the F.C.C. as well as HAM regulations because of the band they are in.

The SWR video is relevant to what we are discussing. The higher the SWR the more energy is being fed back to the transmitter and not radiating out the antenna. This is most likely the reason people are frying their tx units and the major cause for that is a bad impedance match. From what I see of the mod that people do most of it boils down to how precise they make the new wire they replace. I don't think whomever did the initial mod took into account the added resistance of a heavy solder joint or the thick metal SMA connector. My guess is they only did the math for the wave length to figure out how long the wire is.

Btw I was not faulting you for doing the mod. I fully get the reasoning. I am fairly sure you have done your share of soldering and wire making in the hobby over the years and are quite capable to do the mod properly. The statement about waiting while others break their stuff is a general statement and mainly directed at younger more impatient people who must have the biggest and bestest everything.

Thanks PsyBorg - Good information… I’m learning a lot (probably should have done more background work before I jumped). And to your BTW comment… I didn’t take your comment as criticism/faulting (not in the least), I was merely describing my thought process when I see cool things - look for potential ways to use them. Usually I’m way more cautious. My typical stance is to wait for version 2, after the faults of version 1 are fixed. I’m really a tinkerer at heart. I now I want to get some equipment to measure strength of radio frequencies so I can measure and tinker.

I did consider, or rather had an inquisitive thought, the radiation pattern with the 5 dbi antenna, but my thoughts were that they are both whip antennas so the radiation pattern would be the same, right? If the transmitter is pumping out a fixed amount of power, the only way to get more distance is to focus the transmission, which I understand is done by altering the shape of the antenna, or to lose less of the power between the transmitter and the antenna.

I would like to try the Alex Greve’s dipole antenna (just for fun), but I don’t know what the ramifications are. I know that is what he was going to put onto the modified radio… but there was no follow up information that I could find.

What I was perplexed about, which I pointed out in the article, was that the length of the elongated bell shaped grounding plane (if that is what it is called) and the exposed antenna were different lengths (FrSky stock antenna vs. WiFi 6 dbi antenna). I’ve read/watched enough of tuning antennas to understand that the antenna can be tuned to different frequencies by cutting it to different lengths. So, now I need to go back and calculate what the tuning frequency of 5 dbi antenna. Maybe its length is not centered at the frequency range of the Taranis, but for great the general 2.4 GHz bands. Like I mentioned… If I had some equipment to measure I would spend $5 on an antenna and trim it at 0.5 mm distances to see which length works best for the Taranis.

I really don’t understand if the grounding plane (the solid bell that is soldered to the shielding) that covers coaxial cable actually does anything. I thought the grounded shield in the coaxial cable provided all the shielding that is needed. All I could think of is that the bell ground is used as more shielding for the wimpy thin cable that doesn’t have enough shielding. Does the shield length matter? Someone should know.

 

[PsyBorg]

From what I understand about antennas (not very much) is there are several determining factors that need to be looked at when designing and or just using them.

In our case accurate frequency management. This is determined by the exposed part as well as the shape of the actual radiating member. Whether its a straight dipole and the exposed core needs to be specific lengths of the frequency used wave form IE" half wave, quarter wave. Or the shaping of the receiving part of a patch antenna vs the reflective or focusing part. Also the ability for the radiating part to handle the power that is needed to be run thru it. You can't pump a thousand watts thru a single strand of 24 gauge wire and expect it to not simply melt.

Next is the method to prevent unwanted signal injection from happening between the amplifier section of the transmitter to the radiating part of the antenna. Basically shielding. The length has nothing to do with signal transmission only the resistive force within the circuit.

All of those things above factor in as a resistance in electrical terms. This is where impedance matching and SWR (Standing wave Ratios) come in to play. Impedance is the resistive nature of the materials which must be matched to act in parallel (radio transmission is a function of amperage and thus power not voltage) so the voltages stay the same but the projected out put can vary during transmission since we are not working with a straight line (direct) current using a specific waveform to carry our signal be it voice or digital information. This is all measured using a method called SWR. That is a whole mathematical can of worms so I won't even try and explain that. Bottom line is what is done allows you to see what is being output by the amplifiers vs what is being radiated. The difference is the electrical loss getting the signal from the amp to the antenna. That number is best the lower it can be made which is done by impedance matching. If it is too high it can cause enough resistance to the signal that some of it can actually be returned to the amplifier and that is when the magic smoke gets angry and leaves.

I think what is happening with these mods is people are either short cutting the process and relying on so and so did this so I will and what so and so did does not mathematically align with the person doing their mods gear. No component has the exact same electrical properties so a mod like this antenna mod is a "Best Approximation" and not a guaranteed to work in every case thing.

If I had been the guy in that SWR video I would have stopped when I learned that my swr was zero without the wire change after removing the connector at the amplifier.

 

[LitterBug]

Along with what Psyborg was saying, There is a major piece of the formula missing from the guide which is the velocity factor of the Coax cable. This is the speed at which RF travels through the cable at different frequencies. Without this number, you can not accurately calculate the correct length of the antenna element for the required center frequency. Not all coax is created equally. Just because it says RG178 or RG316 does not mean that the electrical properties such as velocity factor are the same. You must know who the manufacturer of the cable is and the exact model number of the cable. Then you need to find the spec sheet for the cable. A difference of 1-2mm may be necessary for two different RG178 cables even from the same manufacturer. Things like the Material of the center element, the foam core, type of shielding (foil or braded for example) and the outer insulation can all change these numbers.


Cheers!
LitterBug

 

[HilldaFlyer]

Along with what Psyborg was saying, There is a major piece of the formula missing from the guide which is the velocity factor of the Coax cable. This is the speed at which RF travels through the cable at different frequencies. Without this number, you can not accurately calculate the correct length of the antenna element for the required center frequency. Not all coax is created equally. Just because it says RG178 or RG316 does not mean that the electrical properties such as velocity factor are the same. You must know who the manufacturer of the cable is and the exact model number of the cable. Then you need to find the spec sheet for the cable. A difference of 1-2mm may be necessary for two different RG178 cables even from the same manufacturer. Things like the Material of the center element, the foam core, type of shielding (foil or braded for example) and the outer insulation can all change these numbers.


Cheers!
LitterBug

Good to meet you LitterBug. That is really interesting. I had no idea that there were so many factors. Sounds like you aim for the middle of the road and hope for the best because you'll never get it exact.

Thanks - David

 

[HilldaFlyer]

Joshua Bardwell found out his Antenna was bad, not his Taranis...

 

[PsyBorg]

Still not a good idea to be modding things unless you have the right knowledge and the skills to implement them. A radio is an awful big investment to experiment with. Like he said he did ignore key factors when doing an upgrade. I am sure the new radio he got where he says the same mod has been done in fact does NOT have the same mod and has been tailored to work on that specific radio.

Knowing large scale manufacturing test methods I am pretty sure every amplifier that goes in a Taranis gets set in a test fixture and the antenna and the connections to the amplifier are custom matched to every one to work within the parameters specified by the build plans all before it even gets installed in the radio.

 

[makattack]

That was a good video... great reminder about ESD sensitive equipment. When I started tinkering with electronics as a kid, that was a big thing. Even at my first job doing firmware (I went away from hardware into software) -- anytime I had to burn my software into hardware and start testing on hardware, we walked around wearing an ESD strap that we plugged/snapped into the bench before even touching the components. Hah, even now, when I see people in the gym walking around with their locker keys on those spiral spring straps, I'm brought back to the electronics lab and wonder why they're wearing their ESD straps in a locker room?

I had gotten away from that practice a long time ago, and gotten to just touching a piece of metal (e.g. a computer case that was plugged in, lamp, etc) out of laziness and the fact that to my knowledge I hadn't damaged anything via ESD.

Anyhow, I knew enough to buy an ESD safe iron, just in case, so that if I were soldering I didn't need to wear a strap, but that just added to my laziness and now even when I'm not soldering, I often times forget to ground myself before touching something like a bareboard Raspberry Pi or an Arduino. Granted, I haven't fried those yet, but the RF boards on the Taranis may be different, and I recall when I was installing the M9 gimbals in my X9D, I wasn't soldering, so I didn't touch my iron which would have discharged the static, nor was I wearing a static strap. I risked damaging my Taranis just by doing that simple mod.

Oops!