Direction Finding - A Team Effort
Locating the RF signal proved to be a team effort on this day, as my hand held yagi was required to get a fix on the very weak signal, first being heard at what proved to be a distance of approximately 12 kilometers.
At that point I was not able to get a solid lock on the direction of the hidden transmitter with the Doppler direction finding unit mounted in my mobile, as the signal was on the light side, not allowing the DDFU to positively identify the direction in which I needed to go.
After pulling over and getting out of my mobile, I scanned the horizon with my handheld yagi and receiver until I had a solid fix on the direction the transmitter lie in.
Once back in my mobile and working my way in the direction of the transmitter, I soon began hearing the signal increase in loudness coming from the speaker of the Doppler finding unit mounted in my radio stack, allowing the unit to give me a reading on the direction to the transmitter.
Typical of hidden transmitter hunting with a hand held yagi, as I got closer to the transmitter, the signal was becoming strong enough that attenuation would be required to continue using the handheld yagi to pinpoint the location of the transmitter.
At that point I put the yagi aside, and I now used the Doppler direction finding unit exclusively, as the advantage is that the DDFU loves the strong RF signal being received from the transmitter, and it locked on solid allowing me to virtually drive right up to the hidden transmitter, and I could have driven right over it if the terrain would have allowed.
Bottom line is both the DDFU and the handheld yagi have their place in direction finding RF signals, and together they are a force to be reckoned with when hunting the source of RF signals.
How it looks from the operator's position at the radio stack.....