Steve B wrote:
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.

Once you have this, don't get complacent. Someday you'll run into a deaf dog.