WEAK-AM

There are a lot of useful calculators online these days. Here is one that I liked from Compliance Engineering: http://www.compeng.com.au/emc_conversion_tables.asp

There are a lot of useful calculators online these days. Here is one that I liked from Compliance Engineering: http://www.compeng.com.au/emc_conversion_tables.asp

This calculator will allow you to enter measured field strength and determine EIRP, or the other way around. For example, data from the test report for the new ChezRadio transmitter shows a field strength of 75 dBuV/m at 10 M. You can enter this value in the calculator to determine the EIRP in mW. Try it– You might be surprised! One caveat: this was apparently a near-field measurement, so accuracy might not be very good. I am a little surprised they didn’t perform this test outdoors, on an Open Air Test Site (OATS). Of course, you do have to be concerned about the ambient RF environment in that case. From this calculation, the predicted field strength at 1 km would be 40 dB lower, or about 56 uV/m. Not earth-shattering, but certainly audible on a good car radio.

Here’s another page with lots more interesting calculators: http://www.rfcafe.com/references/calculator_links.htm