[Milsurplus] [ARC5] 500 Kc XMTR

[Richard]

Long low wires, such as abandoned telegraph wires have been used 
successfully for LF/MF receiving.  RCA had 5 and 9 mile Beverage 
antennas on Long Island for reception from Europe.  I have a 500 foot 
unterminated Beverage which works pretty well.

An interesting option for transmitting is an "on-the-ground dipole."  
Several local experimenters are using them to good effect, about as good 
as a vertical radiator.  At 630M it will be bit longer than 500 feet 
with feed impedance of 200 Ohms. Radiation is vertically polarized off 
the ends.  At HF this would be a dummy load if it worked at all, but at 
LF/MF the ground is more transparent and it somehow works.  I don't know 
how to model this for erp - maybe a field strength measurement. Like the 
Beverage antenna, this will work best over poorly conducting ground.

Richard, AA1P


On 09/17/2017 06:25 PM, Bruce Gentry wrote:
>       Decades ago, Cornell University  generated it's own power and 
> also had a carrier current AM radio station.  On the occasions the 
> university had to connect to the grid, the station was heard far and 
> wide. The RF was able to pass through the big transformers and  they 
> had to install traps to keep the RF on campus. Was there ever any 
> thought of using long distance power lines as VLF antennas? Building 
> traps and antenna matchers to  load into a line carrying 500,000  
> volts or more of AC would be a serious engineering effort, but having 
> several hundred miles of radiator could be quite interesting. With the 
> move to DC for some long distance transmission lines,  have any 
> problems been noted with harmonics generated in the receiving power 
> station radiating as it converts it back to AC?.
>
>        Bruce Gentry, KA2IVY
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