MONEX is short for “monitoring exercise.” These MONEXes are designed to use basic receiving equipment, get you experienced in listening, test your gear, and give you an idea of who is operating in your area and their frequencies. Two of the MONEXes can be done in a couple hours each. The others should take a week or two of intermittent listening whenever you get a chance, preferably at different times during the day and evening. In addition to exercising your technical and listening skills, they also will exercise your research skills on the Internet.
Our first MONEX is a band (or sector) search of the FM Broadcast Band (FM BCB) of 88-108 MHz. To get the most out of this, it should be done with a portable receiver such as a Walkman, or multiband radio with FM BCB reception capability. You can also use your smartphone if it has an FM BCB receiver feature. Barring that, you can always use the radio in your car. These are all inexpensive solutions that anyone can afford or already possess, and what are likely to be used in a disaster and power outage.
FM BCB channel assignments for stations go from 88.10 to 107.9 MHz. with 200 KHz. channel spacing. Start at either end and search your way through the band. Note down every frequency you can receive. Listen long enough to determine the station’s callsign, and to get an idea of the station’s genre. When you finish, take your list and look up the callsigns on the FCC ULS website. Note the ownership of each station, and its transmitter location. Note which stations are owned by the same entity.
After you do this search with the FM BCB, then do the same with the AM BCB. The AM BCB goes from 540 to 1700 KHz. with 10 KHz. channel spacing. Start at either end and search your way through the band. Note down every frequency you can receive. Listen long enough to determine the station’s callsign, and to get an idea of the station’s genre. You will want to do this twice, once during the day and once after dark. When you finish, take your list and look up the callsigns on the FCC ULS website. Note the ownership of each station, and its transmitter location. Note which stations are owned by the same entity. Note the class of each station you’ve found. How many are Class A (formerly called clear-channel) stations? What is the difference in your reception between day and night? BONUS QUESTIONS: Old AM radios had a Civil Defense symbol at two places on the dial. What (specifically) was it for? What are the frequencies? What do you hear on those frequencies? Are they Class A stations?
Those two previous MONEXes used common off-the-shelf consumer electronics equipment. The next MONEX will require at least a basic police scanner with “search” function. If your scanner can receive digital mlodulation types, all the better. This exercise, depending on the level of business/industrial land mobile radio (LMR) activity, can take a couple of weeks to accomplish depending on your level of commitment. This is because unlike AM and FM BCB stations that transmit continuously, LMR communications is intermittent in operation.
For the final MONEX, we will be looking at the frequency ranges of 37.46-37.86, 47.70-48.54, 153.410-153.7325, and 158.1125-158.2725 MHz. The first two sector search ranges are in the VHF-Low LMR band and have a channel spacing of 20 KHz. The last two ranges are in the VHF-High LMR band and have a channel spacing of 7.5 KHz. Before you begin, look at the Industrial/Business Frequency Pool Table listed in 47CFR90.35 (aka FCC Part 90). What are these frequency ranges? What is the specific significance of the frequencies 37.60 and 37.84 MHz.? When you are finished with this research, start performing the sector searches in the specified frequency ranges. Note down every frequency you can receive. When you finish, take your list and look up the frequencies on the FCC General Menu Reports website. Start by looking in your state and county, then switch to a 35-50 mile radius from your location if the first search doesn’t net you anything. Note the licensee of each station, and its transmitter location. Note how far you can receive signals on both bands.
Feel free to post up your results when you are done.
FCC General Menu Reports – https://fjallfoss.fcc.gov/General_Menu_Reports/