Links+radio

hi all

Im at the stage where i need to secure my link to something, my idea was ali plate riveted to the box section and the lonk cable tied to the plate, will this stand up in a battle? if not any other ideas?

also im having bit of trouble with my radio signal the motors pick up interference-i have read the thread about radio signal nd i have ordered some capacitors for all the motors

if i un wind the aerial and secure to the metal plate at the back, the the tip not touching the metal, will this aid my problem?

thanks alex

I glue my links together and then bolt them to ally plate with M2.5 machine screws.

As for an arial you will need something external, either a boat arial or tape it to the top/back of the robot, but this wont be as effective.

For a 40 meg system you need to have your receiver aerial poking out the robots chassis. Preferably as much of it showing as possible. It will get a far better reception if it is vertical. If you have to route part of it inside then try and keep it away from motors and power cables.

Alex ,
Radio waves cannot get to the ariel if its enclosed inside a metal structure... It can find its way in thru something like wood or polycarb etc.
So if youve got any panels made of polycarb Id try taping the ariel to it.

on another post someone mentioned about the length of the aerial, being 80 or so cms but mines nowhere near that length-

its a hitec three channel reciever, would this be causing a problem?

thanks alex

I doubt it ......did it cause problems before?

well it has alwas being twitching ever since i have used it, i was just thinking because mines only 20cms, but the one my dad uses is the technobots one which is so much longer

just thought it might be another cause

also the aerial out of the rx has seen better days, its a bit ragged i do have something i could replace it with, just wondering if it would be adviable to change it? or should i leave it well alone?

alex

By all means change it ... its only a bit of wire.
Id suggest you replace it with one double the length ...then you can chop it back to its original size if you need to.

Try a range test. Plug the rcv into a servo and get somone to walk away with the transmitter until you find a distance at which they can no longer reliably move the servo. If that distance is longer than the distance over which you need to control the robot, than your aerial (in fact your whole radio control link) is OK. If not, add wire up to a total length of 90 cm. At the same time, watch the servo for the twitching you refer to above. If it does not twitch, then the cause of that is somewhere else in your system.

Alex did you get the RX secondhand?
Seems to me that somone might have chopped the wire at sometime and attached the end to an external arial.

I found this list on the web giving RX arial lengths.

KO297FZ 40MHz FM 33cm
KO301F 40MHz FM 33cm
Futaba FP-R103F 40MHz FM 36cm
Futaba FP-R122JE 40MHz AM 40cm
Futaba FP-R122JE 27mhzAM 38cm
Novak XXL 40MHz FM 45.5cm
Hitec HFS-03MM 40Mhz FM 43cm
Jamara XT2 40Mhz FM 45 cm
LRP phaser comp 87400 40Mhz FM 34.5cm
Acoms AR-2/27 mini RX 27Mhz AM 48cm

The following examples are measured to the OUTSIDE of the box:
Futaba R142JE - 40Mhz AM - 49cm
Futaba FP R102JE - 27Mhz AM - 47cm
HPI RX1 - 27Mhz AM - 49cm
Futaba R142JE - 40Mhz AM - 49.2cm
Futaba FP R102JE - 27Mhz AM - 47cm
HPI RX1 - 27Mhz AM - 49cm
Futaba R114F 40Mhz - from outside of case - 69.cm
Futaba R133F 40Mhz - from outside of case - 53.2cm
Futaba FP-R113F 40MHz FM (the non PCM version) 49.5cm

no dont think so jonno got it for me when i first started, mines a hitec ranger III its the hitec in the first list im pretty sure it was never that length but i admit i have shortened it but would only total of a few cms lost

Never mind the theory. Try a range test.

i have tried the range test and it works all the way up my garden 10metres or so, but i will change the aerial anyway

i have measured the aerial and its 38cm i may have cut 5cms off over the yrs but in stages

thanks for the help, if the problem doesnt get better ill re-post

alex

Ten metres is not a lot - you should get at least 30. Is your aerial right outside the robot? Try extending your aerial to 90 cms and see what you get.

well its not like it stopped i couldnt go any further, ill try and do a longer test

If you use just the rcv and a servo you can do the text anywhere. Ive even done it on the pavement outside my house with the whole robot (and someone watching it) while I backed away with the tx.