I can't remember my formulas. If I have a transmitter that puts 1 watt into a beam antenna that has a gain of 8.0DB what is my EFR? Please show the work. I need to be able to demonstrate this to a customer. Thanks alot. Lenny Stein Barlen Electronics.
Just show him the calculator on this site
Should do the job.
Arfa
Lenny-
Charles' method should work for you. If a customer asks, you need to know more about the antenna's gain - is it compared to an isotropic antenna (dBi) or compared to a dipole (dBd)? Note that 0 dBd = 2.1 dbi. An antenna with isotropic gain of 8 dBi would have a gain of 5.9 dB with respect to a dipole.
The isotropic gain is useful for calculating field strength at a distance, but gain with respect to a dipole is easier to measure!
Fred
The calculator that I pointed Lenny at does it for dBi and dBd. A lot easier to just show your customer something that goes ahead and does the job, rather than faffing about in front of him with a calculator, working with a formula and numbers that you're not totally easy with ...
Arfa
That is true, but I assumed that he asked this such that he could re-familiarise himself with the math so that he would be able to demonstrate to his customer how to work it out. Based on my many years of dealing with customers, and making myself look dumb on occasion by trying to explain something that I was not properly familiar with, I just felt that it might look slicker to the customer to be able to just enter the figures and see the results, for both comparison schemes, instantly shown. If he really wants to go down the route of doing it all himself, Google will turn up many hits if he just enters " Antenna ERP " as the search string.
Arfa
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.