Hey, could you guys change the subject as this doesn't seem to have anything to do with line voltages. Thanks, 73's k8sp ----- Original Message ----- From: "Brett Winchester" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, November 13, 2003 6:39 PM Subject: Re: OT - Line Voltages, Frequency in History what this the freq and time for the net please? thank you! BRETT K WINCHESTER PM KD7JN VOLUNTEER & READING SERVICES MANAGER [log in to unmask] http://www.icbvi.state.id.us/brochur= e/RADIO.HTM=20 Member IAAIS International Association of Audio Information Services IDAHO COMMISSION f/t BLIND & VISUALLY IMPAIRED - ICBVI P O BOX 83720, 341 W WASHINGTON, BOISE IDAHO 83720-0012 208-334-3220 ext 104 +7=3Dvoice mail after hours, Fax = 208-334-2963 >>> <[log in to unmask]> 11/13/03 05:41PM >>> Message-Id: <20031113184200.WMDK17368.imf20aec.mail.bellsouth.net@[68.212.9= 8.27]> Martin wrote: >As for why aircraft use 400 HZ, you are all right but there is >even one more reason. While I don't know why the exact number of >400 Hertz, the biggest reason for using a higher frequency is the >size of inductors such as what you have in motors and transformers. <snip> >I think that we'd get pretty tired of hearing that mosquito >whine everywhere very quickly. I get my share of aeronautical mobiles check in with me when I'm ncs for the Maritime mobile service net and you always hear a hint of that 400 hz and its harmonics. Also note that on hf a lot of the aero comms sound like there's a little rf feedback into the audio. Harder to get a good ground up there <grin>. 73 de nf5b Richard Webb Electric Spider Productions "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." --- Benjamin Franklin, NOvember 1755 from the Historical review of Pennsylvania