Improving the range of the firecracker.

[admeeral]

I am using the old firecracker (for the serial interface) and talk to it through a USB / parallel device.
The transmission comes from a small half loop coil which generates a circular polarized signal. This is
not optimum for the typical TM751 which uses a linear antenna.  My firecracker mounts onto a box
which contains the USB interface.  I added an external PC ground plane and connected a short vertical
antenna to the ground plane through a small 3 turn coil.  This coil is situated adjacent to the internal half
loop.  This antenna then acts as a converter from circular to linear polarization.

Because the signal is a transient one I have not been able to come up with a measurement on signal
strength but I have observed that the signal can now reach to the farthest corners of my house, a very definite
improvement.  It also reaches out beyond the pool area.  I hope that this is helpful.

[dave w]

 

[mquintas]

Hi,
Could you post a photo of the antenna mod?
Thanks!