Please guys i need some help. I got a pair of 433 MHz telemetry modules from RCTimer, but the antennas just don't perform. And i want to buy some new ones. I am thinking in buying one of this dipole for the Ground Starion and one of this to use in the Quad. Is this the best configuration? Please help me soon.
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this are flexible(not too much, airflow cant flex them),if you need them stiff add 1 or 2 layers of heat shrink....
A 1/4 must have a counterpoise, to simulate the full half wave. That is why it did not work. Easiest to do, cut a half wave dipole by this formula: 468/frequency in MHz. Some use other than 468, but it will get what you want.
Take a piece of coax, have a connector on one end for connection to your transmitter. Use the formula above. Strip the outside of the coax, careful not to cut the shield wire or middle conductor. Pull the metal shield down over the outside sheath, that is a half wave dipole antenna.
Attach it to your UAV in a manner that let's the antenna hang straight down. Use a Beam antenna for distance, Yagi, Quad, Gizmotchy all work very well.
The real issue is Standing Wave Ratio(SWR). The dipole described should provide an SWR of 1.5 to 1 or less.
Just had this issue. I got 2 new antennas from RMRC, they are great. I got one stiff and one flexible.
http://www.readymaderc.com/store/index.php?main_page=index&cPat...
Stiff: http://www.readymaderc.com/store/index.php?main_page=product_info&a...
flexible: http://www.readymaderc.com/store/index.php?main_page=product_info&a...
gents,
try this on ebay.
search for 433 MHz handheld antenna.
and then change 433 MHz for 70cm.
this is the wave lenght for 433MHz then you will find walkie talkie antennas which are used by hams.
these are great for your base station. and if thats not enough, try to change "handheld" for "mobile " for your base station.
youll need a sma to rp sma adapter or bnc to rpsma etc.
Wilfred ON4NDO.
I am pretty sure that these little radios are actually capable of blowing themselves up when operated with the antenna disconnected.
I blew up my ground station radio not long ago, following a year of faultless operation. The only thing I did differently to usual? I momentarily connected radio to my Nexus 7 prior to connecting the antenna.
Ground Station radio was 433Mhz HopeRF based RCTimer USB module.
Thanks for the info Kirbi, I am always keen to learn more about the RF side of things. I assumed that the apple shaped radiation pattern was ideal.
I will do a bit more research then knock together a new pair and see how they perform.
If you do some research go check a bit at IBCrazy's blogs they have some good designs and documentation.
http://www.rcgroups.com/forums/member.php?u=103113
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