i need the antenna to have a good look and the smallest possible and the best range because i want to put it on an rc car but dont want it to be ugly so any idea ?
actually you are in luck. since it's 900MHz, you'll find planty of different antennas on ebay. just look for GSM antennas (yes - for cell phones).
it all dependes on your transmitter's output power, but i'd imagine that you could easily install tiny antenna on your RC car, and compensate for weeker signal by using higher gain antenna with your reciever.
that's how people usually do fpv - small stuff in the air/field/whatever and high gain antenna (usually directional btw) next to the monitor
patryk:
actually you are in luck. since it's 900MHz, you'll find planty of different antennas on ebay. just look for GSM antennas (yes - for cell phones).
it all dependes on your transmitter's output power, but i'd imagine that you could easily install tiny antenna on your RC car, and compensate for weeker signal by using higher gain antenna with your reciever.
that's how people usually do fpv - small stuff in the air/field/whatever and high gain antenna (usually directional btw) next to the monitor
well i want to build it myself if its possible, and i can't use ebay where i am because it will cost me very big money to get something for 5$ which i can't afford now
@doughboy well those antennas would be great in quality but i am looking for different ones, for example is there anyway to build a rolling antenna like the induction shape and what kind of wire can i use if i want to make something that is similar to an RC car antenna like this one flexible :
if you really want to build your antennas, then that's how i would do it:
wire antenna for the car:
1/2 or 1/4 wave lenght. your wave lenght is ~333.333mm so the antenna would be 166.666mm (1/2 wave) or 83.333mm (1/4 wave). use copper wire and keep it as straight as possible. curved antenna won't perform too well, but might work for you on short distances.
if you want high gain directional antenna for your reciever:
bi-quad design is probably the simplest to build. you can calculate dimensions here: Online Calculator .:. Bi-Quad Antenna
patryk:
if you really want to build your antennas, then that's how i would do it:
wire antenna for the car:
1/2 or 1/4 wave lenght. your wave lenght is ~333.333mm so the antenna would be 166.666mm (1/2 wave) or 83.333mm (1/4 wave). use copper wire and keep it as straight as possible. curved antenna won't perform too well, but might work for you on short distances.
if you want high gain directional antenna for your reciever:
bi-quad design is probably the simplest to build. you can calculate dimensions here: Online Calculator .:. Bi-Quad Antenna
aha that's a good info and about keeping it straight can i use for example the glue paper for electronics apps like the skotch i mean or that will affect the transmission ?
and about the width of the wire how much should it be ? 1mm is good or a lot ?
i would use a wire with insulation on it. this way you won't have to worry about it. 1 - 1.5 mm^2 copper wire should be riggid enough to keep it's shape on it's own anyways.
in any case any plastic/rubber will do (as long as it's not coductive)
patryk:
i would use a wire with insulation on it. this way you won't have to worry about it. 1 - 1.5 mm^2 copper wire should be riggid enough to keep it's shape on it's own anyways.
in any case any plastic/rubber will do (as long as it's not coductive)
actuly i have to buy a copper wire without any cover on it, so i have to do my own so that way u saying that adhesive will be good to go
and about the extremity which i want to attach to the RF link, i just have to solder it right ?
this is the rf link i am using is this one 433mhz attachement file:
youse whatever wire you have. a piece of old extention cable will probably work good btw.
of course you'll have to solder it. how else would you attach it?
the only question is if you want to connect your antenna directlt to the PCB or you want to put it somewhere else in which case you'll need to use a piece of propper coaxial leed (soldering antenna directly would be way easier though).
if you have a piece of decent 75 ohm coax, why would you want to attach antenna to it?
just use cable's core as the antenna. strip it to needed lenght making shure that the screen doesn't touch it, then solder other end to the antenna output, solder screen to the ground and you should be fine.
tv coax will be a pain to work with though. those are rather thick and not very flexible. not exactly something good for RC imo
patryk:
if you have a piece of decent 75 ohm coax, why would you want to attach antenna to it?
just use cable's core as the antenna. strip it to needed lenght making shure that the screen doesn't touch it, then solder other end to the antenna output, solder screen to the ground and you should be fine.
tv coax will be a pain to work with though. those are rather thick and not very flexible. not exactly something good for RC imo
ok then let's forget about it and stick to the copper i will get a copper wire tomorrow and i will start working on it
you have nice copper wire inside coax cable.
copper core of your tv coax will probably do just fine as an antenna. just strip it, cut it and solder it.
patryk:
you have nice copper wire inside coax cable.
copper core of your tv coax will probably do just fine as an antenna. just strip it, cut it and solder it.
ok i will so in the datasheet of my RFs it says antenna should be : Attenna:25cm Single core wire or mutil?core wire
and a remark :
VCC voltage module operating voltage and good power filtering;
A great influence on the antenna module reception, preferably connected to the
1/4 wavelength of the antenna, generally a 50 ohm single?core wire, the length of
the antenna 315M approximately 23cm
Antenna position has also affected the reception of the module, the installation,
the antenna as possible straight away from the shield, high pressure, and
interference source; frequency used to receive, decode and oscillation resistor
should match with the transmitter.
here are some pictures of what i did, i cut a 26.5 cm antenna so 25+1.5cm, i need 25cm which is written in the datasheet of RF
i then stripped it and then i put a heatshrink around
so i need to know if i could have kept the white insulation as cover ?