Where do you draw the power from for your onboard FPV Tx?
- Thread starter mmurfitt
- Start date
R_Lefebvre
Arducopter Developer
Hmmm... I guess I'm the new guy who doesn't know any better breaking all the rules....
I'm using a seperate 2S battery to power the VTx! I was under the impression there is a step-down regulator in the VTx to take it to 5V internally anyway? The manufacturer specifications list 7-12V input. I've never had the 2S go below 7V, so no problem there. If what I think is true (it's got an internal step-down to 5V) then feeding it 8V instead of 12V will result in less heat. Somewhere I had read that the majority of the heat in the VTx is actually from this step-down regulator.
I don't know if I am losing transmission power or not (I wouldn't be if it does in fact use 5V internally...) but all I can say is the results are great. 200mW 5.8GHz, and I've gone out 300m over a neighborhood (ie: noise and reflections) with nothing more than simple CP antennas. I'm pretty happy with that. 300m is bordering on what what is safe and legal, and I don't even have a directional antenna yet (I'm working on that).
Also, I figure the 2S 800mAh battery pack doesn't weigh much more than an external regulator anyway.
I dunno, proof is in the pudding and I don't see any reason to change?
I'm using a seperate 2S battery to power the VTx! I was under the impression there is a step-down regulator in the VTx to take it to 5V internally anyway? The manufacturer specifications list 7-12V input. I've never had the 2S go below 7V, so no problem there. If what I think is true (it's got an internal step-down to 5V) then feeding it 8V instead of 12V will result in less heat. Somewhere I had read that the majority of the heat in the VTx is actually from this step-down regulator.
I don't know if I am losing transmission power or not (I wouldn't be if it does in fact use 5V internally...) but all I can say is the results are great. 200mW 5.8GHz, and I've gone out 300m over a neighborhood (ie: noise and reflections) with nothing more than simple CP antennas. I'm pretty happy with that. 300m is bordering on what what is safe and legal, and I don't even have a directional antenna yet (I'm working on that).
Also, I figure the 2S 800mAh battery pack doesn't weigh much more than an external regulator anyway.
I dunno, proof is in the pudding and I don't see any reason to change?
DesJardins
Member
I personally (after reading so many posts I want to punch my own eye) believe this came up once items were produced such as the TBS core and other similar items that are literally coming on crafts from the shops now.
This is a personal preference item where if you are not flying a mile is to me not a "necessity" now I will say of you want the best clarity it seems like a logical option as well as all the "shielding" and just having things in the right location. I'm struggling for space on my small F450 frame so for me I'm using my little pack until I decide on my frame upgrade. I'm up in the air right now because of a few things...
Anyways I wouldn't take it the wrong way of somebody tells me my little pack is the incorrect method as I know it works but there might be a better way of doing it later on depending on how far I want to take FPV. Serious to just sport flying around for quick fun.
Cheers
This is a personal preference item where if you are not flying a mile is to me not a "necessity" now I will say of you want the best clarity it seems like a logical option as well as all the "shielding" and just having things in the right location. I'm struggling for space on my small F450 frame so for me I'm using my little pack until I decide on my frame upgrade. I'm up in the air right now because of a few things...
Anyways I wouldn't take it the wrong way of somebody tells me my little pack is the incorrect method as I know it works but there might be a better way of doing it later on depending on how far I want to take FPV. Serious to just sport flying around for quick fun.
Cheers
kloner
Aerial DP
guys like trappy that made that list i posted use 25mw 5.8 vtx and get 2-3 miles with zero interferrence...... just sayin
You'll notice that list doesn't say it's the only way, but it's how you want stuff to get the best performance.... if 100 feet away 200 feet up is all your after, no sweat. but if you want to get down 2-3 feet 2000 feet out, better follow them rules to a t
all video transmitters are not alike. when i hear 200mw 5.8 it sounds all chineese........ they may or may not work very well. most guys doing this stuff i follow are using immersion and lawmate video gear. even with immersion, to get killer reception like i spoke they use filtered power going into it..... you have to to get really good range, seperation too, not a 450 or 550 frame but an fpv frame... That's what they are.
it probably does step it down,,, but fall filters are not created equal...... alot of fpv trasmission gear is made for video surveilance plugged into a wall outlet. the only one specifacly made for rc that i'm aware of is immersion. the owner actualy flies fpv
the ext regulators and filters are grams, your pack is oz's
When you come around me and ask about fpv, I'm not gonna tell you how to get 300-500-100 meters, i'm telling you how to fly out 5 miles and hit the deck for a ride of your life. Some people are fine fying around 4000 feet up but that aint me, too easy and boring. i want the ground, and i want gobs of it in perfect reception or i won't be confident to get it down out far and hit it hard.
You'll notice that list doesn't say it's the only way, but it's how you want stuff to get the best performance.... if 100 feet away 200 feet up is all your after, no sweat. but if you want to get down 2-3 feet 2000 feet out, better follow them rules to a t
all video transmitters are not alike. when i hear 200mw 5.8 it sounds all chineese........ they may or may not work very well. most guys doing this stuff i follow are using immersion and lawmate video gear. even with immersion, to get killer reception like i spoke they use filtered power going into it..... you have to to get really good range, seperation too, not a 450 or 550 frame but an fpv frame... That's what they are.
it probably does step it down,,, but fall filters are not created equal...... alot of fpv trasmission gear is made for video surveilance plugged into a wall outlet. the only one specifacly made for rc that i'm aware of is immersion. the owner actualy flies fpv
the ext regulators and filters are grams, your pack is oz's
When you come around me and ask about fpv, I'm not gonna tell you how to get 300-500-100 meters, i'm telling you how to fly out 5 miles and hit the deck for a ride of your life. Some people are fine fying around 4000 feet up but that aint me, too easy and boring. i want the ground, and i want gobs of it in perfect reception or i won't be confident to get it down out far and hit it hard.
Last edited by a moderator:
DesJardins
Member
Having a clear signal without worrying is my goal. I don't have a distance goal per-say but that's why I was looking at the TBS frame as I found out quickly the room is needed to get all the electronics away from eachother.
I hear a grip about shielding wires, I'm all for re-wiring my goods but I also see that the shielding must be conductive not just a heat shrink or mesh. Any suggestions on what I can use to shield my wires?
Specifically the AV tx wires & ESC Leads?
I hear a grip about shielding wires, I'm all for re-wiring my goods but I also see that the shielding must be conductive not just a heat shrink or mesh. Any suggestions on what I can use to shield my wires?
Specifically the AV tx wires & ESC Leads?
kloner
Aerial DP
when we say i don't want to go far, or low, or whatever,,,,, this is a futaba 2.4 system probably going at least twice as far as any spektrum radio i've been around, notice how short the path and how many times i fly by myself.....
same day, same spot, better video tx but more importantly, lrs uhf......
to me the long runs are so worth the extra little bit, but it took me a few months to get that sweet tooth for it. Got tired flying around myself, got tired f trying to drive in as far as i could to get to hills, spots, water, etc. There is a dramtic difference in them two rigs in the same guys hands on the same day, same time, same everything
same day, same spot, better video tx but more importantly, lrs uhf......
to me the long runs are so worth the extra little bit, but it took me a few months to get that sweet tooth for it. Got tired flying around myself, got tired f trying to drive in as far as i could to get to hills, spots, water, etc. There is a dramtic difference in them two rigs in the same guys hands on the same day, same time, same everything
Last edited by a moderator:
DesJardins
Member
Big difference!
kloner
Aerial DP
des, the core installed tbs comes with a shielded video wire, theres enough to do the tx too if you want to. i just twist everything, it keeps them from being little antennas all over my rig, terminates and transmission they would make. if you get one without it, i'll send ya one, i got like 4 of them here
That big this hitec braided wire like servo city has is in everything here... i haven't had a problem till last weekend and that was from spektrum tx's. i didn't know only 2 of the 8 lawmate channels are compatible with spektrum. Friggin spektrum guys were on both sides of me, all day long
That big this hitec braided wire like servo city has is in everything here... i haven't had a problem till last weekend and that was from spektrum tx's. i didn't know only 2 of the 8 lawmate channels are compatible with spektrum. Friggin spektrum guys were on both sides of me, all day long
Last edited by a moderator:
DesJardins
Member
That would be awesome, is it worth twisting the wires like these from my AV tx to my GoPro?
And really with these wires it wouldn't be a twist but a coil...
And really with these wires it wouldn't be a twist but a coil...
Last edited by a moderator:
DesJardins
Member
Ahhh crisp my receiver wires are like that but my ESC & AV Tx wires are the flat "together" wires :-/
mmurfitt
Member
Hey Kilby,
I got myself a 3S 500mAH 11.1v battery for my FPV TX, thanks for the recommendation.
Do you know much about the battery charge?
I'm trying to figure out at what point I need to charge this little sucker.
Can anyone shed any light on what the lower limit of each cell should be before the battery needs charging again?
mmurfitt
Member
That's great, thanks kloner, appreciate it.
I notice the 3.7v is the same as the 4S batteries I use, is the 3.7v the same for these Lipo batteries regardless of size and number of cells?
jforkner
Member
3.7 volt battery = 1 cell x 3.7 volts (1S)
7.4 volt battery = 2 cells x 3.7 volts (2S)
11.1 volt battery = 3 cells x 3.7 volts (3S)
14.8 volt battery = 4 cells x 3.7 volts (4S)
18.5 volt battery = 5 cells x 3.7 volts (5S)
22.2 volt battery = 6 cells x 3.7 volts (6S)
29.6 volt battery = 8 cells x 3.7 volts (8S)
37.0 volt battery = 10 cells x 3.7 volts (10S)
44.4 volt battery = 12 cells x 3.7 volts (12S)
7.4 volt battery = 2 cells x 3.7 volts (2S)
11.1 volt battery = 3 cells x 3.7 volts (3S)
14.8 volt battery = 4 cells x 3.7 volts (4S)
18.5 volt battery = 5 cells x 3.7 volts (5S)
22.2 volt battery = 6 cells x 3.7 volts (6S)
29.6 volt battery = 8 cells x 3.7 volts (8S)
37.0 volt battery = 10 cells x 3.7 volts (10S)
44.4 volt battery = 12 cells x 3.7 volts (12S)
So reading through this thread looking for a voltage regulator to step down the 4s pack to a nice clean and even 12v I have a question about the adjustable regulator you linked to. Can this be safely shrink tubed or is heat dissipation an issue? I'm going to wire in my orientation lights and figure these are pretty good little units to have around anyway.