I'm glad I stumbled across this video as it also serves as a great way to repair busted coax jacks on transmitters. I have a few older FatShark transmitters sitting in a bin and I've been meaning to repair them -- the pads got stripped when the SMA jack was yanked off back in my dumber days when I didn't use an extension and just had the antenna hanging out the backside of the quad. This method will be much easier and more useful than re-attaching the jack.
try holding ya wire cutters over the other way JB, you might get better control of your depth of cut/feel. the single bevel will push your cutters away into you waste side and give you a flat face to strip the wire outter away.
Joshua, my friend, I love ya and frequent your videos often. You have taught me so much and I thank you. Now I want to return the favor and suggest you use a T-Stripper for both shearing wire and stripping them in the most efficient way. I was taught back in the early 70's when I began my electronics career, to never cut any wire with pinching type of cutters (i.e. side cutters). Wire should always be sheared to preserve the integrity of the wire end. All T-Strippers have approximately 1" of proper wire cutters at the bottom of the jaw. Secondly, when you strip something like the flexible coax used on SMA cables in our hobby, the wire gauge sizes available on the stripper will work fantastically on both the insulation (typically 16awg) and the dielectric (24awg). You probably already know all of this, but just in case, there you go. Again, this is out of respect and friendship because what little I can give you as far as new knowledge, you have already given me ten fold. Your greatly appreciated, dave
Joshua, I enjoy your videos. The method which works for striping small wires is soldering iron itself. You can cut isolation without disturbing strands.
Lead free solder re-flows fine. Adding solder to make old factory solder flow better works because the flux core plus the molten solder helps heat the old solder up faster with leaded or lead free. Get the proper tools for the job and you wont have such a hard time. soldering work is easy when you have good proper tools. auto adjust wire strippers are a great tool to have well worth the money.
I am consistently surprised at the number of people that don't have or just don't use a good pair of wire strippers =). None the less this is another good video. In my opinion Mr Bardwell's videos are an asset to anyone in this hobby.
+ for GOOD wire strippers...so much better than fiddling with razor knifes ect. I suspect that the issue is people in this hobby are so used to buying stuff from China that they buy Chinese tools also :)
i de-solder SMA by removing solder as much as i can with fluxed 14AWG wire and soldering iron. after that i put a joint of solder on the side of SMA connector and heat it up. After 10-15 seconds you can gently push SMA by your soldering iron out from the board.. :)
I have that same solder gun. changed my whole solder game! I was using cheap walmart ones, then ordered this one... bam just so much better. those tips seem to last forever too! Ive let it cool several times covered in solder on accident and I still havent ruined a tip!
Bad luck or not, I for one appreciate you leaving in the bits of fail that happen with these tiny things! I like to split the braid at least in two, and use, in this case, the three on top. This provides bit less RF escaping from the unshielded part. It's like a ground plane kinda. Ideally the feed line joint would all be shielded, but that's insane to do. BTW that angle is a right angle coming off the board into the pigtail, so I'd be interested if that makes a real world difference -- That is, if you do one coming straight out (in the same orientation as the original connector). If you wind up doing that I encourage you to compare.
I have done this a few times and the last time I did it I wanted the coax to come out at a right angle from the VTX PCB, so I used hot glue all around the solder joints in a big dollop. Feels nice and sturdy for strain relief. BUT, when I fire it up, the hot glue warms up and gets soft! I guess epoxy would be better...
I had a similar idea of using hot glue to help stabilize an AIO camera, not giving any thought to how hot the TX would get. Needless to say halfway through my first test flight it melted, allowing the camera to re - orient itself in a less than desirable manner and bringing my dreams of becoming a FPV God abruptly back to earth. We live and learn.....
Joshua kudos for showing the mistakes to. Makes us not feel like complete idots and it helps. Mistakes are only mistakes if you forget to learn from them.
Great video Joshua, but there is a much easier and quicker way of removing the SMA connector on the VTX, simply heat the whole connector up with a cigarette lighter or over a gas stove by waving the connector through the flame. Its even enough to de-solder the center pin and the whole SMA connector just falls off. That's how I do mine, done quite a few now.
+crezzee Upon further exploration, I tried just holding my biggest soldering iron tip against the end of the SMA connector, and after a short period, it came right off. Just keep an eye on the heat in the board to make sure you're not overheating it.
Hi. Try to put heatshrink on transmitter, and make cuts for dipswitch and power connector. It's strenght enought, and easy to remove if You want replace coax. To cut dielectric use razor knife. It's way better.
nice video yet again Josh. do you use the 5823 vtx with fatsharks? range? compatibility? I just recently bought a set of predators and am worried about replacing the fatsharks brand vtx every time I break it. I usually don't fly very far like 300ft.
+J dog harrell Yes. I have just started using them, but no problems so far. For the record, I am using F band on the 5823, and I have the Attitude V2 with the Nexwave V2 module, not the newer raceband module. I have not tested every channel on the band, but channel 1 works fine at least.
Thanks, also its good to point out you can use this to also remove the connector to change it out or to add a pigtail with the correct connector........I got an AOMWAY VTX which I accidently got SMA...(I have all RP-SMA Antennas)....I plan on taking out the connector and using a RP-SMA Extension cable I have
As an RF Engineer I cringed a little bit at this haha. But after running some quick numbers I thing you are OK. The rule of thumb is to have the "undesirable geometry" less than 1/10th of the wavelength. For 5.8GHz you just need to make the connection in less than 5mm (pad to fully shielded coax) and the loss should be negligible. It would be really interesting to see a before and after power measurement. Love the videos Joshua, keep up the good work. We all appreciate the help, I know I have learned mountains form your channel.
If you check something like the X4R-SB, you'll see this is more or less exactly how the antennas are soldered on from the factory. I wasn't familiar with the 1/10th wavelength guideline, but I expected that this would be okay just based on copying what someone else did. I mean, ultimately, there aren't too many different ways of soldering coax to a board.
Can't disagree with your results. It looks like a great solution for this application. The 1/10th guideline is kind of intuitive if you think about it the right way. If you take a sign wave and zoom in on it to where you can only see 1/10th of it, the wave looks relatively flat. If it's flat, we can treat it like DC for those dimensions.
i can hear your nose hairs whistling when you breathe hahaha. love your stuff mate, thankyou, you are the one person on youtube i can really trust for good information and you always explain everything very well (sometimes too well but not complaining ;)
Fiddly indeed. I just did that and it was my last antenna too. Luckily I didn't ruin it. Because of the need to fly, I'm doing things I never thought I was capable of.
Hi Joshua, you are mistaken when telling there should be no continuity between signal and ground. There are quite a few VTXs out there with continuity. Don't ask me how those circuits are working, but for example, the eachine TX5258 has a beep between signal and ground right out of the box ;) And yes it's working properly
sooo my question is, does this get the same signal quality as using the preinstalled connector? I have had an MMCX break off inside of the connector, and thinking about doing this to fix it and keep it from happening again in the future
this is your bad day but probably standard day for me! i bought helping hands to hold things but they are a pain. Then i discovered bluetack. a small bit between the table and vtx or whatever is just so helpful on fiddly jobs or even when just tining a wire!
hey man, thx for sharing :) I've made a little "cage" or housing for this purpose out of 1mm copper wire. it's way more stable than just the cable to the contacts and it looks a bit cleaner. I'd like to share it with you and other people who want to put the cable straight to the vtx. I'll send a picture of it via Facebook :) keep it up ...
Wouldn’t the impedance change because you cut the pigtail shorter ? If the cable is too short, or too long it could damage the transmitter ? It’s basically the same as putting on a bad antenna
I had to do this on my emax vtx but my sma.cable broke as well so I directly soldered the antenna to the wire but shortened the antenna in the process so now when.im on channel A8 my signal is actually R3 lol. New AKK X2 on the way along with a camera and some pigtails and extensions.
Hello Joshua, is it really necessary to solder the ground too? I broke my SMA yesterday and just soldered the signal to the receiver, it seems to work but I haven't flown the quad yet, is it bad for the VTX performance or something like that?
Hey Josh, coming back to this video after a while now that I finally have a vtx and a pigtail :D Quick and important question, won't the heat from the heatsink melt the hotglue away?
Turned out didn't do the same, my antenna needed to be routed the other way, and direct soldered an older broken antenna (Had broken the SMA connector) directly onto the VTX, might not be the smartest thiong to do but I NEED TO FINALLY START MY FPV ADVENTURES
Question: when building fpv antennas, you cannot check continuity right? because you are technically connecting the ground and the center conductor with the lobes of the antenna? right? it will ultimately "beep" to display continuity due to the way the antenna is designed.
Joshua, thanks for the demystification how the transmitter connections hook up to the coax cable. But please, the green tape you used; what kind is it?
Oldie but goodie....Question, though: At 16:30 you mention that there shouldn't be continuity between the ground and signal on the TX. Is this correct? I get continuity on 2 different transmitters (with no antenna or power wires connected). Thnx.
Captain Over yeah I also got continuity on two transmitters from different manufacturers with no power nor antenna connected. And this was before I even modified the vtx connector.
I third this. My Eachine VTX got continuity so I cut off my beautiful solder job only to find out the actual board was ohming out between pins. Gonna solder it up again and cross my fingers.
so should't be continuity between ground and signal but it is. I was scared that did something wrong .Even on my new Eachine there is.Can someone explain why?
I know this is kind of random on an older video. But I was looking for a video on why does a VTX heat up? are there any VTX as that run cooler? I have a waterproof drone I'm building where the VTX needs to go inside and I'm worried about it overheating!
That is a valid concern. The vTX heats up because it's a power amplifier, and they get hot. The way to cool them down is to run them at lower transmit power, but of course your range is reduced.
+rodney wickersham they heat up because they have a big amplifier on a tiny board. Use a lower power vTX would be my recommendation. 25 mW will be reasonably cool.
Bardwell I know this is an old video but please explain why I get continuity between ground and signal and have no problems without the antenna connected it's an eachine tx801
flyandride I've tested continuity between antenna and ground on several different vtx makes and models and usually see continuity. Close examination reveals an inductor between the antenna trace and ground, this would show as continuity to dc but not rf. Some vtxs may have a capacitor down stream of the inductor in the antenna trace. In this case it will not show continuity to ground. The capacitor passes rf but not dc. It all depends on the circuit design whether you see continuity from antenna to ground. www.rcgroups.com/forums/showthread.php?2918654-Continuity-between-signal-and-ground
Carl is right. There is usually an inductor on the signal output. RF circuits are not designed for operating at DC frequency, and do not behave the same at DC as they do at 5 GHz or whatever.
There is another use for this video... the legs of my sma connector that are solder onto the board broke... I didn't think of soldering a wire straight onto the board to salvage the board... cause of course, soldering the sma back onto the legs doesn't give it enough strength....
Hi joshua... Want to ask.. I have vtx that center wire and ground wire have touching together when i check with multimeter.. Its that my vtx have broken?
The GND pads are on both sides, for the SMA connector but I'm pretty sure there is only a single signal pad. If there is a pad in the center on the bottom, it's worth a try. The vTX is toast otherwise. Maybe you could scrap back the solder mask to reveal the trace on the top and solder to it... but I'm not sure I would trust my video connection to that.
Joshua Bardwell My SMA is ok, but the JXT that connects to the FC is trashed and missing solder pads where the JXT used to be. I'm pretty sure I can solder video on the left of the 5 pads on the other side (bottom of the black/text side of the VTX , but the real question is if I can do the same with power and ground.
thanks for showing the common made mistakes, some videos like these make things look very easy. this can be disappointing when trying yourself. are you a lefty by any chance? makes me wonder if learning mode2 flying is different for you compared to right handed people. guess we'll never know.
Yes, I'm a lefty. But learning to fly wasn't any different to me. Both hands have complicated stuff to do so they just have to manage. It's like, how come you never see a left handed piano? (Actually, they do exist, but you get my point.) Besides, I've been using game controller's forever!
It'd be better if more FPV transmitters were sold with u.Fl connectors, or at least pads suitable for them giving end users the choice to use u.Fl or direct soldering. It's ridiculous to use connectors that weight about as much as the whole device they're connected to. AFAIK only the ImmersionRC Tramp HV VTX has a u.Fl connector which I think was a smart decision.
SOL, SOL, SOL, SOLDER ) Great info matey I'm going to try this one. Your very brave whenever I make a mistake for a video I edit it out. keep em coming.
Hi Joshua I have just done this mod to my vtx but have continuity between ground and signal but my un modified one is the same out the box is this normal??
@Joshua Bardwell Its not you man, its the tools. This is the wire stripper i usually use. it is $10. i like this 16 to 26 awg stripper better than the common 20 to 30 awg. you can pretty easily score the large jacket with the 16awg hole by not closing it quite all the way. this is much easier than stripping with those cutters. The fact that you did strip that delicate wire with side cutters means you are really good. www.mouser.com/ProductDetail/Jonard-Industries/JIC-1626/?qs=sGAEpiMZZMvsO91yRwFnAMjRVXcq8fe3
+TheWaterbound07 I'm not confident in my ability to desolder the SMA all at once (without a hot air gun anyway) without overheating the rest of the board. With the jeweler's saw, there really is no risk of damaging the board or the pads. It is a very fine saw that offers very good control.
Maybe i got lucky because i did the same thing but with an old USB cable on which i 've only left one wire inside and the armor outside, and connected to a antenna...
It was painful to watch. Get some magnifying glass and exacto knife. I split the outer shield into two strands, just like SMA connector, this way your joint will be much stronger, connecting to the PCB at all 3 points.
This is one of the more entertaining videos I've seen in a while. Not only that you are showing what we've all done before :)
Showing the masses the secret tips of the pros as I figure them out one by one...
+FinalGlideAus Can you explain? I feel like I am missing the joke here.
He is not editing out the mistakes. Most people do.
I'm glad I stumbled across this video as it also serves as a great way to repair busted coax jacks on transmitters. I have a few older FatShark transmitters sitting in a bin and I've been meaning to repair them -- the pads got stripped when the SMA jack was yanked off back in my dumber days when I didn't use an extension and just had the antenna hanging out the backside of the quad. This method will be much easier and more useful than re-attaching the jack.
thanks Joshua for not editing out your mistakes!!! It dose help to know what I'm getting into. Your GREAT and this video is AWESOME!!!
Bonus points for not cutting out the mistakes and making it look like a roach could do it like some people do :)
+highoctanehotrod I figured as long as I was making all the mistakes, everybody could benefit from them. I'm not a proud man...
try holding ya wire cutters over the other way JB, you might get better control of your depth of cut/feel. the single bevel will push your cutters away into you waste side and give you a flat face to strip the wire outter away.
Joshua, my friend, I love ya and frequent your videos often. You have taught me so much and I thank you. Now I want to return the favor and suggest you use a T-Stripper for both shearing wire and stripping them in the most efficient way. I was taught back in the early 70's when I began my electronics career, to never cut any wire with pinching type of cutters (i.e. side cutters). Wire should always be sheared to preserve the integrity of the wire end. All T-Strippers have approximately 1" of proper wire cutters at the bottom of the jaw. Secondly, when you strip something like the flexible coax used on SMA cables in our hobby, the wire gauge sizes available on the stripper will work fantastically on both the insulation (typically 16awg) and the dielectric (24awg).
You probably already know all of this, but just in case, there you go.
Again, this is out of respect and friendship because what little I can give you as far as new knowledge, you have already given me ten fold.
Your greatly appreciated, dave
love the fact you not only show us the best way to do this, but also show us common mistakes!!! thanks Great video
talking to yourself in a very soothing way! thanks josh!
Joshua, I enjoy your videos. The method which works for striping small wires is soldering iron itself. You can cut isolation without disturbing strands.
Not silicone though? Only plastic?
Lead free solder re-flows fine. Adding solder to make old factory solder flow better works because the flux core plus the molten solder helps heat the old solder up faster with leaded or lead free.
Get the proper tools for the job and you wont have such a hard time. soldering work is easy when you have good proper tools.
auto adjust wire strippers are a great tool to have well worth the money.
That's right solder grasshopper 🦗🦗🦗🦗
I am consistently surprised at the number of people that don't have or just don't use a good pair of wire strippers =). None the less this is another good video. In my opinion Mr Bardwell's videos are an asset to anyone in this hobby.
I don't like using strippers on coax. Although they could hardly have done worse than I did.
+ for GOOD wire strippers...so much better than fiddling with razor knifes ect. I suspect that the issue is people in this hobby are so used to buying stuff from China that they buy Chinese tools also :)
This was almost like watching a Bob Ross video. "No mistakes just happy accidents".
i de-solder SMA by removing solder as much as i can with fluxed 14AWG wire and soldering iron. after that i put a joint of solder on the side of SMA connector and heat it up. After 10-15 seconds you can gently push SMA by your soldering iron out from the board.. :)
I'm quite good at electronics and soldering, but I just never thought of doing this. Thank you, Joshua! :D
wire strippers 5$ , entertainment value of your video priceless!!! :)
I have that same solder gun. changed my whole solder game! I was using cheap walmart ones, then ordered this one... bam just so much better. those tips seem to last forever too! Ive let it cool several times covered in solder on accident and I still havent ruined a tip!
Bryson Michael RC at the end of soldering you are supposed to wipe the tip clean and add fresh solder and let it cool that helps prolong the tip
Bad luck or not, I for one appreciate you leaving in the bits of fail that happen with these tiny things! I like to split the braid at least in two, and use, in this case, the three on top. This provides bit less RF escaping from the unshielded part. It's like a ground plane kinda. Ideally the feed line joint would all be shielded, but that's insane to do.
BTW that angle is a right angle coming off the board into the pigtail, so I'd be interested if that makes a real world difference -- That is, if you do one coming straight out (in the same orientation as the original connector). If you wind up doing that I encourage you to compare.
I have done this a few times and the last time I did it I wanted the coax to come out at a right angle from the VTX PCB, so I used hot glue all around the solder joints in a big dollop. Feels nice and sturdy for strain relief. BUT, when I fire it up, the hot glue warms up and gets soft! I guess epoxy would be better...
I had a similar idea of using hot glue to help stabilize an AIO camera, not giving any thought to how hot the TX would get. Needless to say halfway through my first test flight it melted, allowing the camera to re - orient itself in a less than desirable manner and bringing my dreams of becoming a FPV God abruptly back to earth. We live and learn.....
LOL. Great video. Made my morning and I learned something new.
This is the video I’ve been looking for. ⭐️⭐️⭐️⭐️⭐️
Joshua kudos for showing the mistakes to. Makes us not feel like complete idots and it helps. Mistakes are only mistakes if you forget to learn from them.
+Gerard de Vries as many times as I screwed it up, I figured may as well let y'all learn from it.
No heat gun, but he does happen to have a jeweler's saw! 😂 Love it xD
"And now I'm going to solder these wires for all the world to see! Oh damn they moved"
LMAO! Very informative and very entertaining, as always.
Another helpful video from you. Thanks Johua!
Great video Joshua, but there is a much easier and quicker way of removing the SMA connector on the VTX, simply heat the whole connector up with a cigarette lighter or over a gas stove by waving the connector through the flame. Its even enough to de-solder the center pin and the whole SMA connector just falls off. That's how I do mine, done quite a few now.
+crezzee Good tip. I have a butane torch that should do the trick. I guess I was worried about overheating the board.
+crezzee Upon further exploration, I tried just holding my biggest soldering iron tip against the end of the SMA connector, and after a short period, it came right off. Just keep an eye on the heat in the board to make sure you're not overheating it.
Joshua Bardwell best tip!; using the soldering iron on the SMA connector to heat the pins good idea
Hi.
Try to put heatshrink on transmitter, and make cuts for dipswitch and power connector. It's strenght enought, and easy to remove if You want replace coax.
To cut dielectric use razor knife. It's way better.
I know it's a old video but I like your taste in multitools.
nice video yet again Josh. do you use the 5823 vtx with fatsharks? range? compatibility? I just recently bought a set of predators and am worried about replacing the fatsharks brand vtx every time I break it. I usually don't fly very far like 300ft.
+J dog harrell Yes. I have just started using them, but no problems so far. For the record, I am using F band on the 5823, and I have the Attitude V2 with the Nexwave V2 module, not the newer raceband module. I have not tested every channel on the band, but channel 1 works fine at least.
Thanks, also its good to point out you can use this to also remove the connector to change it out or to add a pigtail with the correct connector........I got an AOMWAY VTX which I accidently got SMA...(I have all RP-SMA Antennas)....I plan on taking out the connector and using a RP-SMA Extension cable I have
As an RF Engineer I cringed a little bit at this haha. But after running some quick numbers I thing you are OK. The rule of thumb is to have the "undesirable geometry" less than 1/10th of the wavelength. For 5.8GHz you just need to make the connection in less than 5mm (pad to fully shielded coax) and the loss should be negligible. It would be really interesting to see a before and after power measurement.
Love the videos Joshua, keep up the good work. We all appreciate the help, I know I have learned mountains form your channel.
If you check something like the X4R-SB, you'll see this is more or less exactly how the antennas are soldered on from the factory. I wasn't familiar with the 1/10th wavelength guideline, but I expected that this would be okay just based on copying what someone else did.
I mean, ultimately, there aren't too many different ways of soldering coax to a board.
Can't disagree with your results. It looks like a great solution for this application.
The 1/10th guideline is kind of intuitive if you think about it the right way. If you take a sign wave and zoom in on it to where you can only see 1/10th of it, the wave looks relatively flat. If it's flat, we can treat it like DC for those dimensions.
I've not heard of an RF Engineer before. Was that a major or a discipline you shifted to after completing or while acquiring a EE MS?
Yeah. It's just a specialization of EE. My degree does not say RF.
Nicholas Lantz RF Engineering is like black magic...
I use razor blades to strip coax, and use the roll method with my fingers.
That makes it easy to feel when you reach the wire inside.
+sqwert That's part of the reason I was so confused. I was expecting to feel the blade hit solid core and it was stranded.
teeth work well
hey, just a tip use a triangular file to cut of the connector and use your nails to expose the coax sheaths so you don't cut it
kudos for keeping the bloopers
i can hear your nose hairs whistling when you breathe hahaha.
love your stuff mate, thankyou, you are the one person on youtube i can really trust for good information and you always explain everything very well (sometimes too well but not complaining ;)
Fiddly indeed. I just did that and it was my last antenna too. Luckily I didn't ruin it. Because of the need to fly, I'm doing things I never thought I was capable of.
Hi Joshua, you are mistaken when telling there should be no continuity between signal and ground. There are quite a few VTXs out there with continuity. Don't ask me how those circuits are working, but for example, the eachine TX5258 has a beep between signal and ground right out of the box ;) And yes it's working properly
As a wi-fi specialist, this must be a challenge to investigate ;)
Thnx Joshua. I am going to do this.
all 50 ohm (radio transmission) is fine. if you could physically fit it you could use rg213 which is about half inch outer diameter.
sooo my question is, does this get the same signal quality as using the preinstalled connector? I have had an MMCX break off inside of the connector, and thinking about doing this to fix it and keep it from happening again in the future
this is your bad day but probably standard day for me! i bought helping hands to hold things but they are a pain. Then i discovered bluetack. a small bit between the table and vtx or whatever is just so helpful on fiddly jobs or even when just tining a wire!
hey man, thx for sharing :) I've made a little "cage" or housing for this purpose out of 1mm copper wire. it's way more stable than just the cable to the contacts and it looks a bit cleaner. I'd like to share it with you and other people who want to put the cable straight to the vtx. I'll send a picture of it via Facebook :) keep it up ...
Wouldn’t the impedance change because you cut the pigtail shorter ? If the cable is too short, or too long it could damage the transmitter ? It’s basically the same as putting on a bad antenna
I had to do this on my emax vtx but my sma.cable broke as well so I directly soldered the antenna to the wire but shortened the antenna in the process so now when.im on channel A8 my signal is actually R3 lol. New AKK X2 on the way along with a camera and some pigtails and extensions.
Hello Joshua, is it really necessary to solder the ground too? I broke my SMA yesterday and just soldered the signal to the receiver, it seems to work but I haven't flown the quad yet, is it bad for the VTX performance or something like that?
+Alpha FPV you must solder the ground, yes, absolutely. The range will be very low and you may damage your transmitter.
+Joshua Bardwell Okay thanks, I'm going to correct that :)
Joshua Bardwell 😲 silly questions that people could find the answer to if they only FULLY WATCHED your video!!
Like those sma connectors are solid metal, lol! They are brass coated plastic or some crap like that. I cut them with snips all the time.
Brass is a very soft metal.
Hey Josh, coming back to this video after a while now that I finally have a vtx and a pigtail :D
Quick and important question, won't the heat from the heatsink melt the hotglue away?
+Abdul Aleem Shekhani it didn't for me.
Joshua Bardwell cheers for the reply, I shall be doing this tomorrow and shall report back how it goes for me...
Turned out didn't do the same, my antenna needed to be routed the other way, and direct soldered an older broken antenna (Had broken the SMA connector) directly onto the VTX, might not be the smartest thiong to do but I NEED TO FINALLY START MY FPV ADVENTURES
Some tech 7 is another one for covering solder joints and especially where there is heat JP :)
Question: when building fpv antennas, you cannot check continuity right? because you are technically connecting the ground and the center conductor with the lobes of the antenna? right? it will ultimately "beep" to display continuity due to the way the antenna is designed.
+Mad Yet yes.
Joshua, thanks for the demystification how the transmitter connections hook up to the coax cable. But please, the green tape you used; what kind is it?
+Escape Velocity just electrical tape
Can you shorten the length of the pigtail, and then re-solder? Will this cause any tuning issues?
Should not cause issues. If the pigtail's impedance is correct, length should not matter.
Thanks!
Thank you so much. This video helped me fix my 49$ cricket pro!
Rip to any ones antenna trying to follow along haha
Oldie but goodie....Question, though: At 16:30 you mention that there shouldn't be continuity between the ground and signal on the TX. Is this correct? I get continuity on 2 different transmitters (with no antenna or power wires connected). Thnx.
Captain Over yeah I also got continuity on two transmitters from different manufacturers with no power nor antenna connected. And this was before I even modified the vtx connector.
I third this. My Eachine VTX got continuity so I cut off my beautiful solder job only to find out the actual board was ohming out between pins. Gonna solder it up again and cross my fingers.
I checked 2 NIB VTX and both have continuity between ground and signal. There was a very small amount of resistance though when I tested for that.
so should't be continuity between ground and signal but it is.
I was scared that did something wrong .Even on my new Eachine there is.Can someone explain why?
Captain over I also get continuity between ground and signal I don't understand how he doesn't but my VTX works just as well it's a tx801 from eachine
Been there!! Sometimes you can tie the opposite end into a lose knot so it doesn't pull thru. 🙀
I know this is kind of random on an older video. But I was looking for a video on why does a VTX heat up? are there any VTX as that run cooler? I have a waterproof drone I'm building where the VTX needs to go inside and I'm worried about it overheating!
That is a valid concern. The vTX heats up because it's a power amplifier, and they get hot. The way to cool them down is to run them at lower transmit power, but of course your range is reduced.
+rodney wickersham they heat up because they have a big amplifier on a tiny board. Use a lower power vTX would be my recommendation. 25 mW will be reasonably cool.
Bardwell I know this is an old video but please explain why I get continuity between ground and signal and have no problems without the antenna connected it's an eachine tx801
flyandride
I've tested continuity between antenna and ground on several different vtx makes and models and usually see continuity. Close examination reveals an inductor between the antenna trace and ground, this would show as continuity to dc but not rf.
Some vtxs may have a capacitor down stream of the inductor in the antenna trace. In this case it will not show continuity to ground. The capacitor passes rf but not dc.
It all depends on the circuit design whether you see continuity from antenna to ground.
www.rcgroups.com/forums/showthread.php?2918654-Continuity-between-signal-and-ground
Carl is right. There is usually an inductor on the signal output. RF circuits are not designed for operating at DC frequency, and do not behave the same at DC as they do at 5 GHz or whatever.
There is another use for this video... the legs of my sma connector that are solder onto the board broke... I didn't think of soldering a wire straight onto the board to salvage the board... cause of course, soldering the sma back onto the legs doesn't give it enough strength....
"For the whole world to see. Great, it's moved! Great!" Lol.....
Josh, you need to get a proper pair of Klein wire strippers. They make a model that goes all the way to 26 gauge.
Hi joshua... Want to ask.. I have vtx that center wire and ground wire have touching together when i check with multimeter.. Its that my vtx have broken?
No. Many vTX antenna have DC continuity between signal and sheath. It's normal if the antenna is installed.
@@JoshuaBardwell thanks for info..
I learned something today. I did not know that with antenna connected the circuit is closed
Can you solder video/gnd/power directly on the bottom pads on this? I have one with a broken JXT and lost the pads under the connector as well.
The GND pads are on both sides, for the SMA connector but I'm pretty sure there is only a single signal pad. If there is a pad in the center on the bottom, it's worth a try. The vTX is toast otherwise. Maybe you could scrap back the solder mask to reveal the trace on the top and solder to it... but I'm not sure I would trust my video connection to that.
Joshua Bardwell My SMA is ok, but the JXT that connects to the FC is trashed and missing solder pads where the JXT used to be. I'm pretty sure I can solder video on the left of the 5 pads on the other side (bottom of the black/text side of the VTX , but the real question is if I can do the same with power and ground.
Would liquid electrical tape be acceptable? Instead of apoxy
Yeah it would do okay.
thanks for showing the common made mistakes, some videos like these make things look very easy. this can be disappointing when trying yourself. are you a lefty by any chance? makes me wonder if learning mode2 flying is different for you compared to right handed people. guess we'll never know.
Yes, I'm a lefty. But learning to fly wasn't any different to me. Both hands have complicated stuff to do so they just have to manage. It's like, how come you never see a left handed piano? (Actually, they do exist, but you get my point.) Besides, I've been using game controller's forever!
Hello what cable should I use to prolong vtx?
One from 75 ohm okay?
No, definitely not. RF coax is 50 ohm. RG318 is an okay choice.
Thanks Bardwell! much appreciated
It'd be better if more FPV transmitters were sold with u.Fl connectors, or at least pads suitable for them giving end users the choice to use u.Fl or direct soldering.
It's ridiculous to use connectors that weight about as much as the whole device they're connected to.
AFAIK only the ImmersionRC Tramp HV VTX has a u.Fl connector which I think was a smart decision.
A good roll of desoldering braid will help you with that job.
Is that hot glue going to melt? - the TS5823 gets very hot.
+garthfpv Not yet. But I agree it's not the ideal solution.
wasnt there a follow up to this video where you just heated up the connector and it came off?
+Juanamo FPV yes, but be careful if you do that not to overheat anything.
SOL, SOL, SOL, SOLDER ) Great info matey I'm going to try this one. Your very brave whenever I make a mistake for a video I edit it out. keep em coming.
Just done this to my TS5828S and this way I can fit everything in the stupid woodpecker 235 frame that I'm currently using...
I love your videos Joshua but didn't realise you did comedy too. P.S. we've all done it.
Hi Joshua I have just done this mod to my vtx but have continuity between ground and signal but my un modified one is the same out the box is this normal??
Yes it's normal for a cloverleaf antenna to show DC continuity.
Joshua Bardwell thanks for the reply Joshua but I was talking about the vtx not the antanna
a desoldering pump or desoldering wire should do the same job!
zweeee...weee...weeee and off it goes. LOL
I can fly with RP SMA ?
Thank you. Great idea.
where do you buy your TS5823 from ? there is so many fakes on the market ...
+fpvYou Myrcmart is where I get mine. I have no idea if they're fakes or not, but they're $11 and they work okay for me.
+Joshua Bardwell how fast they ship to us ?
fpvYou I would say about ten days. Sometimes more like 6-7 if you're lucky.
@Joshua Bardwell
Its not you man, its the tools. This is the wire stripper i usually use. it is $10. i like this 16 to 26 awg stripper better than the common 20 to 30 awg. you can pretty easily score the large jacket with the 16awg hole by not closing it quite all the way. this is much easier than stripping with those cutters. The fact that you did strip that delicate wire with side cutters means you are really good.
www.mouser.com/ProductDetail/Jonard-Industries/JIC-1626/?qs=sGAEpiMZZMvsO91yRwFnAMjRVXcq8fe3
why not just desolder the SMA? Seems like there would be a possibility of damiging the pads etc.
+TheWaterbound07 I'm not confident in my ability to desolder the SMA all at once (without a hot air gun anyway) without overheating the rest of the board. With the jeweler's saw, there really is no risk of damaging the board or the pads. It is a very fine saw that offers very good control.
Maybe i got lucky because i did the same thing but with an old USB cable on which i 've only left one wire inside and the armor outside, and connected to a antenna...
can someone explain the rohs thingy?
solder wick or solder pump make light work of this and I don't think signal gain is gonna be worth it!
Seriously - wire strippers, FTW!
The first part is the "how not to do" part :)
Every single time I strip wires.
Wire strippers are overrated. I prefer a lighter and fingernails :-)
me too bro, also Female strippers are overrated, I prefer a box of tissues and
wood wax :-)
I use my teeth almost exclusively!
or you could have just used desolder wick
I don't think desolder wick would work for releasing an SMA. It can't really get up underneath the connector where the solder is.
It was painful to watch. Get some magnifying glass and exacto knife. I split the outer shield into two strands, just like SMA connector, this way your joint will be much stronger, connecting to the PCB at all 3 points.
+RC Pilot Multirotor If you think it was painful to watch, you should have felt what it was like to record.
Not so great on the tools
Here's a good way to secure the wire and you don't need to pull the braid back. i.imgur.com/ISW48QD.jpg
+compudaze That's a good approach. Just solder the braid directly to the pad without pulling it or twisting it.
Makes it nice and firm. Can pull thew crap out of it without effecting the signal wire inside.
Why do you not have a decent set of strippers?
I do. I just hate using them.
What the hell is happening use the right tools and sale them too you dummy!
lol fun eh