how far will a 100 milliwatt am transmitter travel in miles?

Answer 1

1/8 to 1/2 mile

Answer 2

The answers here are all over the place and people are looking for a good guess estimate working with radio all my life (FCC first class license and an Amateur Extra) I think I can give a better way to answer.. In a micro power broadcaster set up (most transmitters are either a mono channel (which has no stereo pilot ..believe this or not that alone will increase range (more on that later) or a two channel FM stereo signal, AM broadcasters (in the AM band) face a lot more issues with range (more on that) ... OK... with a 100 mw ( 1/10 th of a watt) or less transmitter into a vertical whip antenna..i.e 2 - 3 ft (the most common kit or small station purchase) and with the antenna and transmitter indoors.. I have always found the signal to be very good ANYWHERE in a average size home (please note, these frequencies 88 - 108 Mhz can easily penetrate walls and doors unlike frequencies in the WiFi (802.n) band or 2Ghz.. as you go outside the signal will fade quickly after 50 to 100 meters (even with a sensitive hand held fm receiver) .... so almost any radio technician will start to tell you that your transmitting antenna is the key to everything ..when it comes to range... and there is alot of truth here.. if you could build a matching circuit on your micro-powered broadcaster to effectively couple all the transmitters energy into the antenna who would see a major change in range... I mentioned the mono (not stereo) transmitters reaching further... that is because for proper stereo demod ... the pilot signal must be strong enough to sync the receivers stereo decoder (hence the received signal must be stronger or receiver closer to the transmitter to work.... that circuit is not enabled in a MONO broadcast...

Answer 3

For practical (as opposed to the theoretical C * how long it has been on!), this will depend heavily on both the quality of the aerial and of the ground system.

With a dense ground mesh under damp soil for a hundred meters around the aerial and a resonant aerial (note that this normally means a capacity hat on a vertical for small site working) you will go a few miles or so, with an electrically short whip and no worthwhile ground, you will only get a few meters...

Is your restriction on transmitter output power or on effective radiated power?
I ask because with a electrically short (say 10M vertical with a capacity hat), you will be looking at a radiation efficiency of only a few percent, so assuming you are restricted to 100mW ERP (Effective radiated power) you would be looking at around 5W RF power into the ATU. With only a 100mW transmitter output, your effective radiated power would be a mighty 2mW or so!

For reference, in the UK we have special event broadcast stations (on a so called 'Restricted Service License'), where these are on the MW band, they are restricted to 1W ERP from a 10M mast, the standard line up is a 50W carrier power transmitter feeding the ATU into a top loaded vertical. This is listenable 5 Miles or so away depending on ground conditions.

Regards, Dan.

Answer 4

Expect about 50 to 200 feet range, depending on local conditions, with the standard wire antenna. The signal will be very strong everywhere within your home.

If you want to maximize your range, check out our instructions for building a Part 15 compliant outdoor base-loaded vertical antenna. With this antenna installed close to ground level, expect 1/2 to 1 mile strong-signal range. Range will increase to 1 to 2 miles when the antenna is elevated to 20 feet or more.

Answer 5

I think distance = transmitter power * receiver sensitivity, but you also need to consider other transmissions, hills, climate/atmosphere. Lot to it but you can make a lot of difference with the receiver. How many others are transmitting on the same wavelength?

Answer 6

It also depends on the gain of the receiving and transmitting antenna. With a big enough antenna and line of sight you could probably go 100 miles.

Answer 7

in practice it depends on the external conditions and how good is your reciever. In theory it could go to the reaches of outer space and take a long time to get there, getting progressively weaker by the square of the distance. But if you had a powerful enough receiver you would pick it up.

Answer 8

The transmission of the 100 milliwat travels at the speed of light 185000mps. If you can provide the amount of time, it woould be helpful.

Answer 9

It depends on the sensitivity of the receiver.

Answer 10

As far as anyone takes it.