I subscribed to some electronics newsgroups, but as of yet haven't passed
through their process to get messages.

I want to build an ultrasonic dog repeller. I do real estate inspection,
and there are times that I encounter either obnoxious dogs or aggressive
dogs. I carry pepper spray, and have almost had to use it, pitbulls both
times.

I have this little blue box that works pretty good on my two dogs when they
raise Cain from a visitor or a knock on the door. But its range is not that
good. It runs on a 9v. battery, and is a Big Lots item.

I would like to build one that is very strong, both for gaining some range,
and gaining the dog's attention.

Researching this, I find the 20,000 - 60,000 hz. range to be within their
hearing. Is there anywhere I can buy a simple tone generator, or kit that
will let me build one of these. Is tone generator what I need to be
searching for, or is there another term?

I see several on the market, but they are lax to state just how strong they
are, or their range, mostly seeming to be aimed at home training at short
distances.

TIA

Steve