What's happening with this xmitter in a pipe?

Greetings All,
I had to drop a camera down a 6 inch diameter steel well casing to see
what was going on. I used one of the tiny ubiquitous color cameras
with a built in transmitter. I don't know the what the transmitting
frequency is but the antenna wire is about 2 inches long. The camera
was lowered down the well casing without touching the sides ar
anything else. While watching the image on a little monitor the image
would degrade in certain spots. The degradation was repeatable and
only happened in certain spots. Is this because the signal bounces
inside the casing and interferes with itself?
Thanks,
Eric

 

Possibly it came close to a nearby power main cable,
possibly a cable TV drop (though not likely), or
perhaps some large piece of metal was just getting
between the xmitter and rcvr.

 

Maybe be pipe is acting as a waveguide, setting up standing waves...
at certain spots, you get negative reinforcement.
Several equidistant blank spots would lend support to this hypothesis.

 

I agree.