My first caller was a jonny stewart caller. It was basically a tape deck, 25 feet of speaker wire, loudspeaker & battery. I think it weighed about 7 pounds. I used this call successfully on red fox. The Jonny Stewart does work and is loud. The tapes are available in a wide selection of choices. The best part of this system is the wide choice of sounds available to you. The down side of this unit (in my opinion) is that it is heavy, bulky, and rolling out the wire is a pain.
I have since switched over to a Foxpro Plus caller. This thing is amazing. It is small enough to put in a coat pocket and all the sounds are digital. The sounds are pre-programmed at the factory. The Foxpro is very loud and very clear. I also have the optional remote control with mine which allows me to switch sounds, adjust volume, or mute it at up to 100 yards away. The Foxpro caller is a bit pricey but is well worth the money (in my opinion). The remote is also a very good option. Check out the Foxpro Link......good information. [url]http://www.varminthunters.com/foxpro/[/url]
Also, John Dillon, the owner of Foxpro is a great guy to work with. He will even play the sounds for you over the phone if you call him. Good luck.