[Antennas] Studies of propagation and signal strength ofaviation antennas

[Jim Dawson]

Over the last 25 years I have made many trips across the Atlantic and Pacific in 
corporate jets
and worked a fair amount of DX from altitudes ranging from 28,000 to 45,000 
feet. Like Dave
says, frequency assignments are ruled by propagation. We always had two 
transceivers and I
usually commandeered one to use for DX.

It made an otherwise boring trip enjoyable. I have worked guys at my destination 
and later
met up with them.

Jim - K9DD

----- Original Message ----- 
From: "Dave Holford" <holford at cogeco.ca>
To: "Henry Mei'l's" <meils at get2net.dk>
Cc: <antennas at mailman.qth.net>
Sent: Saturday, June 26, 2010 6:18 PM
Subject: Re: [Antennas] Studies of propagation and signal strength ofaviation 
antennas


> Almost all of my operations were below 5,000 feet, usually much lower, and
> with 100W to inefficient antennas transatlantic comm was normally not a
> problem. If you listen to the MWARA (Major World Air Route Area) comms they
> are very much ruled by propagation. Typically each route has 4 or 5
> frequencies - i.e. 3/6/8/11/13 and 17Mhz assigned and they choose
> frequencies as propagation changes. I have never heard anyone assign a
> frequency on the basis of aircraft altitude, it is invariably on the basis
> of geographical location. Google MWARA for a list of global HF frequencies.
> Military operations have similar sets of frequencies and operate in a
> similar manner.
>
> For example go to www.ips.gov.au (Australian Government Radio and Space
> Services) and take a look at the hourly HAP charts  - select HF systems,
> Global HF, HAP Charts, Hourly HAP Charts and pick a global location. Gander
> is a good choice since they have separate hourly charts for each frequency
> family A,B,C,D,E,F. New York is similar but they have a much smaller area of
> responsibility and less options.
> The frequency selections are strictly geographical with no consideration
> given to altitude.
>
> Dave
>