[ContainerTed]

Thinking back to my military days, we used a heavily grounded solid copper wire caged room to repair those little emergency transmitter devices. The cage prevented the signal from escaping the shop area and creating a hassle with the control tower.

The cage may have a lot to do with your signal problem, but I also suspect a power deficiency as well. The openings in the wire weave would have to be very nearly the same distance as the wavelength of the frequency used by the transmitter (an example here would be the door of a microwave oven allows you to see into the cooking area, but blocks the microwave from coming out. Anything between the transmitter and the receiver with this kind of weave structure, or anything large made of copper or ferrous methal can drop your signal level.

And, if the radio frequency used by the device is very high, like into the gigahertz range, then anything wet (as in water) can block signals. The microwave range of frequencies are very susceptible to this. That's how microwave ovens heat water - the water catches the energy and converts it to heat. That's why you lose signal on satellite dishes when a huge rain storm comes between you and the satellite. Even leaves on trees can block signal because of the amount of water in the foliage.

I agree with the postings above. Set the transmitter just outside the greenhouse structure and see if you get signal.

Ted
(Who is an old electronics bench tech)