2-Meter Simplex frequency use
In the Amateur Radio 2 meter band the band plan allocates a section for simplex operation. There are about 6 mainly used frequencies in the 146Mhz part of the band and another 6 in the 147 Mhz bands. As far as I know, you do not find FM simplex frequencies anywhere in the 144 or 145 Mhz segment of the band. But who needs the lower two Mhz. when you have so many options on the top two Megs. You could always use the output frequency of a repeater pair to talk simplex on any repeater pair. However, as a general principle, it would be best to avoid using an “active” repeater output for simplex. In Pott. Co., the ARES group designated the simplex frequency of 147.495 Mhz. for ARES simplex operation if needed. Other area ARES organizations have done likewise and these are:
Douglas County ARES 146.580 Mhz.
Sarpy County ARES 146.460 Mhz.
There are 26 recommended FM recommended simplex frequencies in the 2 meter band. Some hams have, in the past, decided that any frequency within the allocated simplex band plan section is fair game. Perhaps so, but like so many other things in Ham Radio, if people cooperate and use the system of regularly spaced simplex channels, there should be enough for everyone. E.g. some years back, a couple hams decided that a nice round figure like 146.500 sounded like a good simplex frequency. They would get on there regularly and chat. It probably wasn’t the best choice because it was too close to the “regularly spaced” simplex frequency of 146.490. So the rhyme and reason to the regularly spaced simplex frequencies is that they are far enough apart not to create adjacent channel interference. There is some wisdom to the band plan. So if you are looking for a FM simplex frequency, here is a list of the main ones used in the 146 & 147 MHz bands.
146Mhz. 147 Mhz.
Starting with 146.43 Notice the 30 Khz spacing 147.42 Again, every 30 Khz
146.52 (Nat. Calling Freq) 147.51 packet
Because these are sometimes used by other groups, don’t let that stop you from using it if you want to. These groups do now “own” the simplex frequency, they just designated it as one they would use if needed or maybe they just like to hang out there and chat. For obvious reasons, you might avoid the packet frequencies.
Having looked at the 30Khz. spaced frequencies above, there are more frequencies if you consider the frequencies half way between the ones already listed, or going with a 15Khz. spacing. For example, if you look at the list above, between 146.43 and 146.46 frequencies is 146.445. Using this frequency should not interfere with either 43 or 46. These are acceptable FM simplex frequencies also. So here is the list of the “in-between” frequencies:
146 Mhz. 147 Mhz.
146.415 (low power) 147.405 (low power)
146.505 147.495 (Pott. Co.)
146.565 147.555 (packet)
146.595 (low power) 147.585 low power
So with these two lists, there are a total of 26 possible simplex frequencies using a regular spacing band plan, and that doesn’t include all the repeater output frequencies mentioned. So there should not be any problem finding a simplex frequency if you need one. Anyway, this information should be helpful and provide ample options for simplex frequencies.
- -submitted by Terry Lindsley KSØL, 03/05/03