Ye Old Simplex Frequencies
As I was writing this, I have been back only a few hours from an ARES (Amateur Radio Emergency Service) Simulated Emergency Test (SET). We were testing the ability to send and receive digital data via radio. The scenario was that there was a tornado that had gone through downtown Lawrenceville. Damage assessments had been made and we were called upon to relay the assessment data through a control point where it was fed to the Emergency Operation Center (EOC).
We had a couple “fixed” stations. They were in vehicles that stayed put during the exercise. I was one of the mobile stations. We mobile operators moved to several locations and communicated to the fixed stations, using both voice and digital, on simplex frequencies. How refreshing it was to use simplex!
Simplex operation has both advantages and challenges. There are some disadvantages. One was the more limited range. Yet, I was again surprised at just how far a simplex frequency can travel. The fixed station that I communicated with was on the top floor of a parking garage, and I traveled from location to location. All my locations were several miles away. I only had problems communicating from one place, and part of the reason was likely that my transmitting location was in a low spot. I was only using five watts on my end, as well. I am sure that if I had used a base station, it would have made a difference.
I recall some other memorable simplex QSOs (contacts). Once I spoke from my home location, using my outdoor antenna, to a friend who was several miles away.
On another occasion, my wife and I were coming home from a trip to Florida. I was monitoring the two meter simplex frequency of 146.520 MHz. All of a sudden a ham radio operator came on and was talking to a nearby friend about this marvelous ten meter opening he had on his HF rig. We followed their conversation for a number of miles. It may have been up to an hour that we were able to monitor their QSO.
The second disadvantage of using simplex it there is no “beep tone” or other indication that your signal is getting out. On a repeater you can hit your transmit button and get some kind of acknowledgement back if your signal gets through to it. With simplex, you have nothing. During this exercise, I was trying to contact my fixed station for several minutes. I thought they were ignoring me. I tried another portable that I had, and that one worked. I looked at the original radio I was using and found out that I had reduced the power from high (5 watts) to “Extra Low”. I had no idea how low the power was at the time, but it wasn’t enough for the fixed station to hear me.
The third disadvantage of simplex is that few people use it. This is the only thing about simplex that we as ham radio operators can change. I say let’s call a friend, whether by phone or by radio and have him or her meet you on a simplex frequency. That would allow us to use seldom used frequencies. It also gives us a measure of privacy, as well. Oh, and another thing: it’s just plain fun to use simplex!
73, David Harden, KJ4CMY