Hi Anthony:
For efficient transmission of radio signals the antenna should be at least 1/4 wavelength in size. At 60 kHz a
wavelength is 5,000 meters so a 1/4 wave is 1250 meters (4100 feet). If the antenna is smaller than 1/4 wavelength the
efficiency goes down. So if you were to wrap a room/house with a coil of wire and with an impedance match drive it with
a 60 kHz signal the signal would fall off very quickly.
There's a license free band in the US between 160 and 170 kHz (1750 meters) where you are limited to a 50 foot antenna
and one Watt input to the transmitter. It's quite a challenge to be heard a hundred miles away. Instead of the 37 Ohms
antenna impedance of a 1/4 wave vertical you have an antenna resistance that's a thousand times smaller. That means the
effective radiated power is in the milliwatts.
--
Have Fun,
Brooke Clarke, N6GCE
https://www.PRC68.com
axioms:
1. The extent to which you can fix or improve something will be limited by how
well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
-------- Original Message --------
G'day time nut friends
I wonder if one of you could point me in the right direction on how to purchase (if one exists) a Time Signal
Transmitter for use at the local level (range 20m) for synchronising watches and radio clocks using the various
standard radio frequencies?
And for the transmitter itself to receive / synchronise it's time using NTP?
I am in Australia and we are out of range for the normal transmissions...
Kind regards to you all
Anthony Dunne
Sydney, Australia
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