Sure, we'll be building space stations with gravitational wave transmitters as soon as we can figure out how to wiggle stars and planets in a controlled fashion to produce them. That should happen Real Soon Now.
"[F]or instance, a 1-second-life black hole has a mass of 2.28×10^5 kg", and the time taken seems proportional to the cube of the mass. So a 2.28×10^6 kg black hole would take 1000 seconds, and so on.
How massive was the black hole in the story?
They definitely mention it being smaller than an atom, though.
Some quick formulas (M is mass of the hole in kg):
Evaporation time T = 8.4 x 10^-17 M^3 seconds
Hawking radiation power W = 3.6 x 10^32 / M^2 Watts
Hawking radiation pressure at 10^-10 meters (roughly one atom) distance P = 9.6 x 10^42 / M^2 Pa
(Note that the last formula assumes that the hole's horizon radius is smaller than 10^-10 meters, which it is for Niven's hole.)
For M = 10^14 kg, we get:
T = 8.4 x 10^25 seconds (which is more than 10^18 years)
W = 3.6 x 10^4 Watts (36 kW, comparable to your car's engine traveling on the highway with a family and luggage, but pretty darn bright for something that's basically just a light source)
P = 9.6 x 10^14 Pa (almost 10^10 atmospheres!)
So this hole won't accrete matter, because anything that gets close to it gets violently pushed away by its Hawking radiation. It will tunnel its way through Mars and out the other side, and then back again, executing simple harmonic motion, indefinitely.
As for the radius... Looks like the Schwarzchild radius is proportional to the mass, and for the moon (7x10^22 kg) it's 0.11x10^-3 meters, so this 10^14 kg mass should be maybe 1.5x10^-13 meters, which is 1.5 x 10^-11 cm. Nice. It looks like Niven did his homework.
Incidentally, Wiki says that Hawking argued for black hole evaporation in 1974, and Niven's story won an award in 1975, which I assume might indicate it was published around then. Seems it'd be a close call whether Niven heard about it before publishing his story.
[1] http://iopscience.iop.org/article/10.1088/1475-7516/2018/07/...
If memory serves the signal of the latter should have been ~3 orders of magnitude higher.
Using nukes to communicate is a bit intense, but a tuned receiver should be able to pick up lower energy levels.
Did you take into account that in a process like this, virtually none of the energy released can be put into gravitational waves? The efficiency of such transmission is extremely low for processes involving ordinary matter--many orders of magnitude less efficient than for electromagnetic waves. You need huge quantities of matter to overcome this problem--or, alternatively, you need very dense matter, like neutronium, or strong spacetime curvature like that of a black hole (but not too large a hole, since curvature at the horizon goes like the inverse square of the hole's mass).