[RFI] 6m spur ADDENDUM...

[Gary Peterson]

I did not finish my last email to this list, as I had to leave for an appointment.

If anyone wants to transmit audio over a fairly large area, FCC part 15 is much more lenient for unlicensed transmissions on the AM broadcast band.

The power limit is 100 milliwatts input to the final stage of the transmitter.  Maximum antenna length, including ground leads, is 3 meters. The part 15 device may not cause harmful interference with any licensed station.

To maximize efficiency, which maximizes coverage, choose an unoccupied frequency as high in the AM BC band as you can.  Vertical antennas, of a given size, tend to be more efficient as the frequency increases, because of a higher radiation resistance and lower capacitive reactance.  The lower X sub C requires less lossy inductive loading in order to effect an impedance match.  You may also learn a lot about vertical antennas, their loading and impedance matching.  

I have a legal, part 15 AM transmitter in our home, that I can feed with any audio source desired.  This includes ham rig, communications receiver or satellite radio.  We live on just under 4 acres and I can hear my transmitter anywhere in the yard with a Sony Walkman or a GE Superadio portable.  I have read about legal, part 15 AM installations that produce a listenable signal almost a mile from the antenna.  Your mileage may vary.  Local ground conductivity is a variable.  Have some fun.

Gary
KzeroCX