More interesting in the permanent self congratulation you see on here when someone buys a rig!
Best regards, Tim Hague Skype m0afj.Tim Sent on my iPad On 16 Jul 2013, at 23:11, "Rich" <r.br...@googlemail.com> wrote: > Am I the only one wondering what has any of this got to do with Elecraft?? > > Can the moderators put an end to all of these OT posts and return it to a > reflector for its purpose please?? Yes I know where the delete button is but > the threads get longer and longer. > > Nothing personal Mike, just picked your post to reply to. > Sent from my BlackBerry® wireless device > > -----Original Message----- > From: Mike Morrow <k...@earthlink.net> > Sender: elecraft-boun...@mailman.qth.net > Date: Tue, 16 Jul 2013 18:02:36 > To: <elecraft@mailman.qth.net>; <k...@yahoogroups.com> > Reply-To: Mike Morrow <k...@arrl.net> > Subject: Re: [Elecraft] OT: Aircraft radio FM > > Ken wrote: > >> AM aircraft radio has been around since the end of spark and >> steadily growing world-wide since that time. It was solidly in >> place -long- before FM was a gleam in Armstrong's eye. > > Er...I'm not sure how that supports an argument that transition > to FM was *at any point and time* considered *by any responsible > party* to have characteristics that were more desirable than AM > for aircraft communications. > > The characterization that AM was "solidly in place -long- before FM > was a gleam in Armstrong's eye" refers accurately only to the era > when aircraft communications were only on medium and high frequencies... > an era when long-range aircraft communications often still made use > of Morse CW (hence the FCC Element 7 exam for Aircraft Radiotelegraph > Endorsement, now discontinued). > > The transition from MF/HF to VHF for aircraft communications received > its greatest push with the UK's pioneering use after 1940 of aircraft > AM command sets operating in the range of 100 to 156 MHz. This sparked > the allied US military's transition from MF/HF command sets to VHF > command sets, one of the earliest being the Western Electric 233A set. > At this point, VHF FM could have been *very easily* adopted, had it not > been for its undesirable capture effect. > > Aircraft VHF-AM was chosen long after FM had been developed. The > decision to use AM was purposely made. The adoption of aircraft VHF-AM > was NOT the result of constraints from earlier legacy technology. > All civil aviation eventually adopted the military standard of VHF-AM, > although up to the mid-1950s many private aircraft continued to use > MF/HF sets with receivers in the 200 to 400 kHz range and a transmitter > on 3105 (later 3023.5) kHz...still far from a universal commitment > to VHF-AM at that late date, had VHF-FM been a better choice. > > Further, by 1945, the US military began exploring UHF for aircraft > comms. These new sets had no reason to stick with AM, if FM were > superior. But FM was not superior...or as good. AM was chosen for > use in the military UHF aircraft band as well. > >> It remains that the staggering cost of conversion to FM is the >> real reason it continues today. > > That is a gratuitous assertion for which my decades of study in this > area finds no substantiation. > > 73, > Mike / KK5F > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
