FPV cam, noise on goggle screen

FatCatRC

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what would cause what looks like lightening bolts to go across the screen in my fpv goggles? I have the cam wired to a 5v bec/power hub in my kraton and noto and when I accelerate and brake etc it shows what I can only describe as mini lightening bolts and static going across the goggle's screen. Do I need to solder in a cap somewhere, and where would that be. The way I have it wired is a harness that I made to split the battery lead to run into the esc and to the bec/power hub then the cam is wired direct to the 5v "cam" lead on the bec/power hub. I needed to use a bec/power hub because the eachine cams I'm using are rated for 3.6-5.5v max so the receiver would put out too much power to wire the cam to that instead of the bec/power hub. If I need a cap what size and where should I install it.
 

suchtragedy

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https://oscarliang.com/capacitors-m...gy.&text=Reduced video noise in your FPV feed
If your fpv cam is an all in one unit with a self contained video transmitter then put a capacitor inline between the +/- lead coming out of it and the bec. I have only used fpv cams with a separate video transmitter and the video transmitters I use can take input voltages up to 35v so in my one car I have fpv in I tap power leads from the main battery plug which has its own capacitors inline already.

You shouldn't need a super big one, like 470uF size would be fine I think.
 
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This can be easy or complex.
Simple fix, use a cap as per @suchtragedy, pretty much any CAP will do and any voltage higher than your BEC. If that works consider yourself lucky and don't read on. Note: These caps are polarized, pay attention to positive and negative, they will blow up like fire crackers if reversed.

By default, your 2 power lines should be twisted, ensures that the noise is more or less equal on both lines in case it's external noise.

This could be a high frequency or low frequency power issue. The large cap will fix your low frequency problem. If you still have noise, place a second cap in parallel, should be in the 4.7nF (ceramic) range, they are much smaller and not polarized. Values are a pure guess but close enough.
If that still doesn't work, you probably need an inline coil with your power line. At the end of the day you are building a filter.
Something like this:

Good luck!
 

FatCatRC

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This can be easy or complex.
Simple fix, use a cap as per @suchtragedy, pretty much any CAP will do and any voltage higher than your BEC. If that works consider yourself lucky and don't read on. Note: These caps are polarized, pay attention to positive and negative, they will blow up like fire crackers if reversed.

By default, your 2 power lines should be twisted, ensures that the noise is more or less equal on both lines in case it's external noise.

This could be a high frequency or low frequency power issue. The large cap will fix your low frequency problem. If you still have noise, place a second cap in parallel, should be in the 4.7nF (ceramic) range, they are much smaller and not polarized. Values are a pure guess but close enough.
If that still doesn't work, you probably need an inline coil with your power line. At the end of the day you are building a filter.
Something like this:

Good luck!
okay thank you, I got some caps on the way from amazon. I'm looking at this vtx to increase my range and the vtx does 1200mw, what antenna should I use? I heard if you don't use the right antenna I'll burn out the vtx. heres a link to the one I want https://www.amazon.ca/gp/product/B07BF9T48V/ref=ox_sc_act_title_5?smid=ADP3MHCS3NLR7&psc=1
 

suchtragedy

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I've had a couple AKK vtx's and they are decent for their price and 1200mw is a lot of power (in fpv air applications that's good for 10+ miles), I'd probably only run it at like max of maybe 200mw because the higher the output the more heat it will generate and those get super hot pretty fast (and just to give you perspective the all in one units and units in microquads is usually only 25mw).

That one you linked can do up to 6s for input voltage so if the cap thing doesn't fix it maybe try getting power off the main power plug to the battery (assuming you're not running above 6s).

For antennas you will probably be better off using an omnidirectional one, I prefer the lollipop style or pagoda style and a brand I've used and like is Foxeer. Just be sure your antenna on your goggles matches the polarity of the antenna on your car, they make these antennas in both left hand polarized and right hand polarized and if you have a different polarization on each end the range is going to very limited and image will have bad noise.
 

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I've had a couple AKK vtx's and they are decent for their price and 1200mw is a lot of power (in fpv air applications that's good for 10+ miles), I'd probably only run it at like aax of mayne 200mw because the higher the output the more heat it will generate and those get super hot pretty fast. That one you linked can do up to 6s for input voltage so if the cap thing doesn't fix it maybe try getting power off the main power plug to the battery (assuming you're not running above 6s).

For antennas you will probably be best odd using an omnidirectional one, I prefer the lollipop style or pagoda style and a brand I've used and like is Foxeer. Just be sure your antenna on your goggles matches the polarity of the antenna on your car, they make these antennas in both left hand polarized and right hand polarized and if you have a different polarization on each end the range is going to very limited and image will have bad noise.
okay thank you for the help. Do I need a super expensive antenna to handle the power(I want to use the 1200mw) or would this work? https://www.amazon.ca/ZicHEXING-Gog...0238066&s=toys&sprefix=fpv+a,toys,177&sr=1-69 or https://www.amazon.ca/gp/product/B076H5TV62/ref=crt_ewc_title_dp_3?ie=UTF8&psc=1&smid=A3OXSXIHCGXXP4
I've had a couple AKK vtx's and they are decent for their price and 1200mw is a lot of power (in fpv air applications that's good for 10+ miles), I'd probably only run it at like max of maybe 200mw because the higher the output the more heat it will generate and those get super hot pretty fast (and just to give you perspective the all in one units and units in microquads is usually only 25mw).

That one you linked can do up to 6s for input voltage so if the cap thing doesn't fix it maybe try getting power off the main power plug to the battery (assuming you're not running above 6s).

For antennas you will probably be better off using an omnidirectional one, I prefer the lollipop style or pagoda style and a brand I've used and like is Foxeer. Just be sure your antenna on your goggles matches the polarity of the antenna on your car, they make these antennas in both left hand polarized and right hand polarized and if you have a different polarization on each end the range is going to very limited and image will have bad noise.
and I think the rhcp vs lhcp antenna is what my problem is right now, I have stupid low range like 200 feet. I bought a cheap aio cam unit from ebay with a soldered antenna and I'm just using a cheap set of box goggles with "diversity" I think the antenna on the cam and the goggles are opposite of each other and don't match. I proved my theory though and got to try fpv with the cars but now I want them to go a bit farther and be clearer because I think this idea is badass and so much more fun than just jumping the cars and smashing them all the time.
 
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suchtragedy

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okay thank you for the help. Do I need a super expensive antenna to handle the power(I want to use the 1200mw) or would this work? https://www.amazon.ca/ZicHEXING-Goggles-Mushroom-Antenna-RP-SMA/dp/B08DXY19RG/ref=sr_1_69?crid=5LPCZWYW4QKC&dchild=1&keywords=fpv+antenna&qid=1600238066&s=toys&sprefix=fpv+a,toys,177&sr=1-69 or https://www.amazon.ca/gp/product/B076H5TV62/ref=crt_ewc_title_dp_3?ie=UTF8&psc=1&smid=A3OXSXIHCGXXP4

and I think the rhcp vs lhcp antenna is what my problem is right now, I have stupid low range like 200 feet. I bought a cheap aio cam unit from ebay with a soldered antenna and I'm just using a cheap set of box goggles with "diversity" I think the antenna on the cam and the goggles are opposite of each other and don't match. I proved my theory though and got to try fpv with the cars but now I want them to go a bit farther and be clearer because I think this idea is badass and so much more fun than just jumping the cars and smashing them all the time.
You don't need a super expensive antenna, but the VTX you linked is using a MMCX connector for the antenna and the ones you linked are SMA.
 

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You don't need a super expensive antenna, but the VTX you linked is using a MMCX connector for the antenna and the ones you linked are SMA.
the vtx comes with a cable to go from mmcx to sma. What decibal range do you recomend for the vtx and what dbi for the googles? I'm sorry for all the questions I'm making my list to order now.
 

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You shouldn't have to worry about the gain numbers too much, those numbers vary depending on the type of antenna and the radiation pattern it makes. A high gain antenna may say 14db or something but that is probably only because it's radiating in a 60 degree beam pattern so when you are outside that beam arc (like if its behind you) you lose signal. An omnidirectional antenna is doing a 360 beam pattern in all directions so it will be the same whether its in front of you or behind you, but the gain numbers you'll see on those types of antennas will be lower, like 1.5-3db. For FPV ground applications whatever you pick is going to be fine because you aren't going very far compared to like fpv drones, even though you are low to the ground it should still be more range than you need.

https://oscarliang.com/how-antenna-gain-affects-range/
 

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By the way, legally you have to stay below 25mW, you are planning on 500x. You don't need that power in any situation unless you are literally 10 miles out. You will cause yourself a lot of issues and reception is most likely very crappy. Receivers can't handle this close range power. I used to be at 25mW and fly around my house without a lot of interference. 10mW in an open field. No change at 100mW other than heat.
 

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By the way, legally you have to stay below 25mW, you are planning on 500x. You don't need that power in any situation unless you are literally 10 miles out. You will cause yourself a lot of issues and reception is most likely very crappy. Receivers can't handle this close range power. I used to be at 25mW and fly around my house without a lot of interference. 10mW in an open field. No change at 100mW other than heat.
I may not use the higher power but I want it if I need it. They can't charge me unless they catch me.
 

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What some don’t understand is that over powering a signal could potentially burn out your gear faster. In point to point radio systems for networks I install, if we aim them perfectly, we generally have to attenuate the signal so we don’t burn them out. We are usually shooting for a -50db signal. Much hotter than that and they won’t survive long. Much lower than that and they won’t be able to carry their rated capacity. Be careful boosting a signal needlessly.
 

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There is really no need for this kind of power and 1W of power might melt stuff. I doubt your antennas can deal with it but RF is a little bit black magic and I'm no expert.
 

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There is really no need for this kind of power and 1W of power might melt stuff. I doubt your antennas can deal with it but RF is a little bit black magic and I'm no expert.
I'm waiting for an email back from AKK to tell me what antenna they recommend for 1000mw, also I will be installing a cooling fan specifically for the vtx as I know they normally get cooled by passing air from the quad props and this vtx comes with a heat sink to install for cooling.
 

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Fyi my RushTank vtx at 800mw will run on my bench to test for only like 3-5 mins before it gets too hot to touch and borderline hot enough to start melting plastic.

My vote is do 25mw first and work up one step at a time then stop when you no longer see any improvement. I tend to obsess over having everything at max output just because I like to always be over the top but when it came to vtx's I learned my lesson the hard way that you shouldn't use more than you need, unless you like buying new stuff to replace things you burn up all the time lol

Fyi this is the fpv car I have that I like most, 25mw and perfect for indoors (not so great with dogs who try to eat it but still).

20200916_115754.jpg
 

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Just asked an RF expert on power for an antenna and he gave me a the same kind of look that I freely hand out when someone asks me if my Kraton is gas or electric :ROFLMAO:
Any antenna is fine. Told you it's black magic !
 

FatCatRC

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Like I said I probably won't use 1000mw but I want to be able to do it if I can. At the end of the day I'm just trying to make it have a clear signal until I run out of range with my dumbo rc, rn I can't even get half way down the street without major signal loss.
 

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I have been. I'm just not happy with the range I have now. The aio cams work but not very far, now if it's due to the antennas not matching or to something else I still want to change to this vtx. I don't like how I can't change the antenna on the cam. I probably will never use 1000mw but I just wanted to make sure I got an antenna that would work incase I want to try it. The vtx will be cooled by a high cfm fan and not installed in an enclosed box or anything like that. Just like my computer and my rigs I like to over do it and try to get the biggest and baddest even if I don't use all the features. On another note I finally got my dvr to work.
 

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