This may at first seem like a strange post to a Ham Radio newsgroup,
but I am hoping someone can help us out. We (Canadian Scientists) are
currently conducting research in Brazil near the city Rio Claro in Sao
Paolo state. We study lizard physiology and hibernation, and are
currently conducting a year long study using radio telemeters
implanted inside lizards. These telemeters allow us to monitor heart
rate, breathing rate and body temperature, and all of this information
is uploaded via radio frequencies and recorded to computer.

The telemeters themselves work in the high MHz range. Each animal (we
are currently looking at 4 animals) has a unique telemeter with a
unique transmission band. The 4 frequencies we are looking at a
182, 184, 206 and 208 Mhz. This radio frequency information is then
decoded with a demodulator, and the information stored as a voltage
signal on a standard computer acquisition system.

The problem we are finding is that typically, between 11am and 3pm
during the day, our telemeters are encountering massive interference
from some external source, and we cannot make any meaningful
recordings. Our signal strength goes to pot, and all we get is noise.
Strangely enough, during the evenings, the recordings seem fine.

To add to the story, all the telemeters can be turned on or off (they
have a battery that should last about 1 year) using a 1.8 Mhz burst
(we have a small battery powered wand-like antenna that we wave over
the lizards for this express purpose!). Once we started to encounter
our interference problem, we began to think that perhaps our
telemeters are being turned on and off intermittently by an external
source of 1.8 MHz. That was when we realized that Ham Radio operates
from about 1.8 to 30 Mhz.

What I wanted to ask the newsgroup was whether anyone thinks that the
signal strength from a local ham radio operator would be enough to
turn our telemeters on or off (I doubt you would know the answer to
this question, but thought I'd ask). Do Ham Radio operators typically
use 1.8 Mhz?

Otherwise, does anyone out there know what could possibly be
interfering at the higher frequencies (182-208 MHz)? There is a local
airstrip and flying club that flies overhead where we are conducting
this research, but I do not know if they typically transmit within out
frequency range!

But more importantly, if the Ham Radio signal could be the source of
our interference, we wanted to know if anyone could help us find out
if there is anyone in Rio Claro that is a Ham Radio operator?!! If
so, would they be willing to help us troubleshoot this problem!

Thanks for your time. Please reply directly to this email if you can.

Gjtatters