How to Hear Meteors on Your FM Radio
Hearing Meteors on the Radio
There are always meteors burning up in the Earth's atmosphere, and during certain times of the year there are major meteor showers. You want to watch the meteors but it's cloudy or the moon is too bright or you live in the city with too much light pollution. Even if you can't see the meteors, you can still have fun listening to the meteors.
When a meteor burns up in the Earth's atmosphere, it leaves an ionized trail in the ionosphere, the part of our atmosphere that reflects radio waves. The trails that these meteors leave are ionized and will reflect radio waves off of them. If you happen to be listening to an FM radio during this, you might be able to hear these distant radio stations reflected to your location, sometimes from as far away as 1000 miles.
It is also fun to camp outside watching the meteor showers while at the same time listening to a portable FM radio. Sometimes you will see a meteor and not hear a meteor ping on the radio and other times you will hear a meteor ping and not see the meteor.
Major Meteor Showers:
- Quadrantids: Night of January 3rd / Morning of the 4th
- Lyrids: Night of April 21 / Morning of the 22nd
- Eta Aquarids: Night of May 6
- Perseids: Night of August 12 / Morning of 13th
- Orionids: Night of October 21
- Leonids: Night of November 17
- Geminids Night of December 13
The Perseids, the Geminids and some years the Leonids are very good meteor showers. It is always best to check each year to get the peak date and times of each meteor shower as they can change each year.
You can hear meteor pings and long meteor bursts with just about any decent FM radio. A radio with a digital tuner is very helpful so you know exactly what frequency you are listening to. A decent home stereo AM/FM should work fine. Boom box type radios don't usually work very well for this. Car radios actually work great for this. I have gone out to watch meteors and used the car radio many times, watching the meteors and hearing them on the car radio.
If you want to get into this hobby more seriously, there are some radios that are better than others. I have used a factory car radio out of a Chevy Blazer and it has worked great, car radios usually have very good sensitivity and can be found cheap. Many times someone will take out the factory radio and install an aftermarket car stereo. You can find these factory car radios very cheap at garage sales, flea markets and online. You can start with an AM/FM radio or FM stereo you already have, hook it to an outdoor antenna and give it a try.
Radios that are popular with hobbyist are the Denon TU-1500, Sony XDR-F1HD and the Sangean HDT-1. Some will modify the Denon by taking out the factory filters and putting in narrower filters. This helps the selectivity of the radio so you can hear distant stations right next to frequencies that local stations are on.
FM radios that come with RDS can be very helpful when identifying radio stations. RDS will show you a readout of the call letters, slogan, song playing and other information. The above mentioned radios all have RDS.
Many communications receivers also cover the FM band and are excellent for hearing meteors and DX'ing the FM band with. One such receiver is the Icom IC R75.
Many of today's new radios only have the extended whip antenna for the FM band and no jack for an external FM antenna. These radios can also work well for hearing meteors on the FM band and other stations during sporadic-E openings.
Using only the external whip antenna on a portable Sony IC-2010 radio, I was able to hear many distant FM stations during meteor showers and sporadic-e openings with the radio on the dining room table.
You can find some great FM receivers on eBay that will work great for FM DXing at low prices.
Antennas and Rotators
To hear more meteor pings, a small outdoor directional beam antenna works well. A good small antenna is the FM-6 made by AntennaCraft, but recently that has been discontinued. Since the FM band starts where the old analog TV channel 6 is, a VHF TV antenna will work (channels 2 thru 12). Since moving to digital television, you might be able to find an old VHF only TV antenna that someone wants to get rid of.
You can build your own FM antenna or buy an antenna that covers the FM and television band like the Winegard Platinum Series HD7694P Long Range TV Antenna.
The antenna doesn't have to be very high; 15 to 20 feet (4.57 to 6.1 meters) above the ground works fine. You can support the antenna with antenna mast from Radio Shack or some other support. Putting it along the house or patio roof works fine. Just make sure you don't put this near any power lines or you could be electrocuted if it should fall. You will also need some coaxial cable to connect the antenna to the radio. This will be 75-ohm cable, which you can also get at Radio Shack or at other electronic stores on the Internet. You can buy the coax with connectors already on at places like Radio Shack, Best Buy or the Internet or coax without the connectors and put your own F connectors on.
You might want the ability to rotate the antenna to different directions. If you have the mast on the ground, you can just turn the mast by hand. If you put it on the roof, you would need a rotator to turn the antenna. Having an antenna rotator makes it easier to turn the antenna from your radio desk while listening as your turn the antenna. A good antenna rotator is the Channel Master 9521A.
Some might think that putting a booster or amplifier at the antenna will help with weak signals. This can actually make things worse as it causes splatter from FM stations on adjacent frequencies.
What You Can Hear
Once everything is up and running, you will want to get familiar with your local FM band. Get a guide that lists all of your local FM stations. You probably won't be able to use those frequencies. Go across the FM band and record the stations you hear that aren't in your area, you will hear a number of them that are 100 or more miles away. You wont be able to use those frequencies either unless you have a directional antenna that allows you to null that station. Find the clearest frequencies and those are the ones you will want to stay to listen for meteors.
During a meteor shower, listen to the clear frequencies and you will hear very short "pings" that last from a second to a few seconds. Other times you will hear a distant station for over a minute. You will also hear numerous stations at the same time. Radio station signals will bounce off of these ionized meteor trails and that is what you will hear. Sometimes you will hear enough to identify a station. If your FM radio has RDS in it and if the meteor burst is long enough, the RDS readout might identify the station for you. Meteors are more prevalent in the early morning hours, but of course some meteor showers can peak in the middle of the day.
Call Letter Search
You can look on eBay for used FM radios like the Sangean, Denon and Sony models listed above or you can get started with portable FM radios. Portable type FM radios are not as good for FM DX’ing and hearing meteors as a FM radio or car radio because they usually do not have a jack for an external antenna. Many times the only FM antenna they have is the whip antenna, which can do fine in a good sporadic E opening. I have used portable FM radios sitting on my kitchen table with just the whip antenna during a sporadic E opening and listened to stations 1000 miles away.
One of the better AM/FM/SW portable radios is the Panasonic RF-2200. Unfortunately this radio was discontinued. You can still find them for sale on eBay.
Hearing Meteors with a Software Defined Radio
Software Defined Radio (SDR) is a great way to hear meteors using your computer. SDR software turns your computer into a very high end receiver with filtering that allows you to listen to the FM radio band. In fact, you can listen to the entire radio band from below the AM broadcast band, the short wave and ham radio bands to above the FM broadcast band.
These SDR computer radios just connect to a USB port in the computer and then you connect an antenna(s) to the SDR module. These SDR radios have great features like superb filtering, the ability to set the filters, being to record and RDS.
RDS is probably something you have already seen, where your FM radio scrolls station information. The RDS with some of these SDR receivers are very fast and they show what is called the PI code. Each station has a PI code, and when a station suddenly shows up on a frequency, the SDR computer receiver will show the PI code. You can then look up the PI code and instantly know what radio station you heard. This is of a great help since you don’t have to wait for the RDS to scroll or wait for a station ID.
Since meteors are so fast, this ability to ID a station makes listening to meteors and identifying a radio a lot of fun. Using software called RDS spy with the SDR receiver works great. You can look up the PI code online and get the call letters, location, power and more information at WTFDA.Org website. Here is a screen shot of what an SDR computer receiver looks like.
A Software Defined Radio (SDR) can be as cheap as about $20 or as expensive as thousands of dollars. A very good and affordable is the AirSpy HF+. If you plan on recording the FM band or a certain frequency, make sure you have a large hard drive. This sure makes it easy and interesting to listen to meteors and watch them at the same time, or even sleep.
You can set the SDR to record while you are away or sleeping and then listen to the recording when you get a chance. You will be able to listen to the FM stations that were reflected off of the meteor tails and that your radio received.
One popular SDR is the AirSpy HF+. If you want to try out SDR while you learn all about them, a popular and very affordable SDR is the RTL-SDR. You will then download free software to use the SDR. Many use the SDR Sharp or SDR# software.
Software Defined Radio
This is a good entry level SDR that is very affordable for anyone wanting to try SDR.
Sporadic E Propagation and FM DX'ing
The hobby of listening to distant FM radio stations is popular and is called FM DX'ing. DX stands for distance. You can listen to distant FM radio stations at times other than meteor showers.
If you invest in an FM antenna and radio, you don't have to use them to listen to only meteors. During the spring and summer months, you can also listen to distant FM stations with a type of propagation that is called sporadic E.
In the northern hemisphere, the sporadic E season usually starts in mid May and can go until September. In the southern hemisphere it occurs around the December 21 solstice. No one knows for sure what causes the ionization of the E layer of the ionosphere, but when this occurs, it can reflect VHF radio signals at distances up to 1,200 miles and sometimes more. There has been speculation that the sun, sunspots or thunderstorms causes sporadic E but none of these theories has proven out.
During a sporadic E opening, the FM dial can be filled up stations and for hours at a time, allowing you to ID many different stations. People in the center of the United States can hear stations from the east and the west coast and also Canada and Mexico during a summer. People living in the Southeastern US can hear into Central America and the Caribbean.
Sporadic E Propagation Tools
Here are a couple of ideas and tools you can use to get your FM radio antenna up. Antennas for FM DX’ing do not have to be that high off the ground, and 15’ to 20’ above the ground should be fine. If you want to mount it on the roof, a tripod would work with just a short piece of tubing. A rotor would work best for a roof mounted antenna. Winegard makes tripods that work well for this, like the Winegard SW-0010 Tripod Mount.
Whether you mount your FM antenna on the roof using a tripod or on the ground with supports, using tubing like the kind Channel Master sells works great. You can support the mast or tubing along a wall or use the supports of a patio roof, either works just fine.
If you are going to support the FM antenna on the ground using a wall or a post, you will need something to hold the mast in place. There are many types and sizes of brackets that will work. If you mount your antenna on the ground, you can turn it by hand towards the direction you are interested in. A rotor is easier though, but generally during meteors or a sporadic E opening, the direction can stay the same for hours.
© 2009 Sam Montana