[Boatanchors] New MF Amateur Band Approved at WRC- 472 to 479kHz

[Richard Knoppow]

----- Original Message ----- 
From: "Bry Carling" <bcarling at cfl.rr.com>
To: <boatanchors at mailman.qth.net>
Sent: Friday, February 17, 2012 8:41 PM
Subject: Re: [Boatanchors] New MF Amateur Band Approved at 
WRC- 472 to 479kHz


> Oh really? Daytime conditions on the 500-550 kHz range 
> seem VERY good here in Florida
> with signals traveling WELL beyond the horizon.
>
> On 17 Feb 2012 at 20:24, Drew P. wrote:
>
>> David Stinson wrote:

     Well, keep in mind that before the broadcasting 
explosion of 1922 the Navy used mostly frequencies in what 
became the broadcast band. Night time coverage of medium 
wave can be extensive but transmitting antennas have to be 
big to have any sort of efficiency and ground systems are 
critical. Lower frequencies can have longer daytime 
distances but antennas become huge. The Navy still uses ELF 
for communication with submerged submarines, these are in 
the range of 10khz to 15khz and penetrate sea water far 
enough to allow reception at periscope depth with no exposed 
antenna. However, the transmitting antennas are perfectly 
enormous and power is in the millions of watts.
     When 500khz was still being used by ships I was able to 
hear commercial stations at least 500 miles distant in the 
daytime and much further at night, but these frequencies 
were used mostly for fairly short distance communication, 
the HF bands being used when the ships were at sea.
     There is a good deal of literature on the radiation and 
propagation of long wave radio in the literature, both very 
old and pretty contemporary.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com