Do Pokeradars work because mine only found me a mightyena and a ponyta..

I think they are just as rare if you use the chaining technique... But the more you encounter Pokemon the more times you have a go at finding a shiny... The only shiny I ever found was in Pokemon gold. It was a spinarak. I encountered it within an hour of first starting the game, and I had nooo idea what a shiny Pokemon was... I deletad it to play the game again and I regret it to this day.

Well of course they work. Use them in other grass patches.

Oh wait, you're trying to chain Pokemon to catch shiny pokemon? Well, use the Poke Radar once, then battle the Pokemon you run into. Then, you should notice some more grass patches shake. Go in the shaking grass patch that's farthest from you. It should be the same pokemon. Keep doing that, and after you've chained that Pokemon about 40 times, you should be on the lookout for a shiny version of that pokemon.

However, if you want to run into some different Pokemon, just use the Poke Radar in different grass patches on different routes, and just walk in random shaking grass patches.

Lol, of course the Pokeradars work, if they didn't you wouldn't have been able to see that Mightyena. Are you using the Pokeradar in different patches of grass, if not then you will continue to encounter the same Pokemon over, and over again.

Shiny Pokemon are rare to encounter, even if you chain them by using the neat, little Pokeradar trick that most of us use. Go in a patch of grass, and activate the Pokeradar, and run into the closest patch of grass that is shaking, and encounter the pokemon. After you finish fighting the Pokemon, run over to the next patch of shaking grass, and fight the Pokemon again. Keep doing this technique, called chaining, until you get over 10 Pokemon in a row, then if you see a silver streak in a patch of shaking grass, run to it, and it might be a shiny pokemon. Don't feel bad if it is not a shiny Pokemon, they are still rare, even if you use this technique.