> Wes is quite right for the USA at least, and to make it easy > on us the FCC defines a 1/2 wave dipole as a "0 dBd" antenna > even though most 1/2 wave antennas show some gain over isotropic.
Is that a dipole in free space or a dipole over ground? A dipole over ground will generally have a peak gain of 8.3 to 8.5 dBi depending on the dipole mounting height and the angle (elevation) at which the measurement is made. Given the efficiency of a mobile whip, transmitter output power could probably be 500 watts before the ERP would be equivalent to 50 watts to a dipole with 8.5 dBi gain. 73, ... Joe, W4TV > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Ron > D'Eau Claire > Sent: Wednesday, May 06, 2009 10:32 AM > To: [email protected] > Subject: Re: [Elecraft] Driveway Distortion Demolition Derby > > > Wes, N7WS wrote: > > But the rule is 50 ERP, defined as 50 W into a 0 dBd antenna. > A mobile whip has a lot lower gain than 0 dBd, in case > that's where you were headed. > > ------------------------- > > Wes is quite right for the USA at least, and to make it easy > on us the FCC defines a 1/2 wave dipole as a "0 dBd" antenna > even though most 1/2 wave antennas show some gain over isotropic. > > It's up to the Amateur to document their antenna's gain if > not using a dipole. From 97.303(s): > > "Licensees using other antennas must maintain in their > station records either manufacturer data on the antenna gain > or calculations of the antenna gain." > > As Wes points out, that might allow using more than 50 watts > output into a small whip. It also requires running less than > 50 watts if using a gain antenna. > > Another difference between Hams and some other non-commercial > radio services is that traditionally most Hams take following > the rules quite seriously, whether or not any government > agency is watching us at the time. > > When one of our members doesn't, we take it upon ourselves to > point it out in the spirit of self-regulation. > > Ron AC7AC > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
