Mysterious signals from 1000 light years away

Moderate Mammal wrote:
http://www.newscientist.com/news/news.jsp?id=ns99996341

Mysterious signals from 1000 light years away
snip
There are other oddities. For instance, the signal’s frequency is
drifting by between eight to 37 hertz per second. “The signal is
moving rapidly in frequency and you would expect that to happen if you
are looking at a transmitter on a planet that’s rotating very rapidly
and where the civilisation is not correcting the transmission for the
motion of the planet,” Korpela says.
..
The relatively rapid drift of the signal is also puzzling for other
reasons. A planet would have to be rotating nearly 40 times faster
than Earth to have produced the observed drift; a transmitter on Earth
would produce a signal with a drift of about 1.5 hertz per second.

My first thought was that it might be on a satellite (or moon) orbiting
a planet at low altitude. But if I understand this correctly, the
orbital period would have to be 1/40 of an Earth day, i.e. 36 minutes.
Around what size planet would you have a low orbit period of 36 minutes?

But maybe the number 40 isn't correct? Wouldn't the factor be linear in
the ratio of observed drift vs. Earth-wise drift? I.e. if the observed
drift is between 8 and 37 Hz/sec, and the drift that would be observed
from a transmitter on Earth (as seen from a "stationary" observer, I
assume) would be 1.5 Hz/sec, wouldn't the factor be between 8/1.5 (=
5)and 37/1.5? (= 25) Giving putative orbital periods of between 270
minutes and 58 minutes, which would seem much more reasonable.

Mike McSwell