J
JasonW
Guest
Hello All,
I just found an interesting indoor 160 meter attic antenna that should work just as well for Part 15 AM: http://www.qsl.net/g3pto/roofant.html
As it is longer than 3 meters (and thus I'd ONLY use it during severe storms or other emergencies to keep a Part 15 AM station on the air), it could be electrically shortened for use with a Part 15 AM transmitter's stock "short antenna" matching network by adding a variable capacitor in series between the transmitter's antenna terminal and the antenna wire.
This antenna is a folded vertical with a top-mounted loading coil and a wire "fan" top-loading capacitance hat connected to the *lower* end of the loading coil. Since the antenna is folded, the loading coil is actually at a low height and is easy to gain access to for fine-tuning.
Using the designer's "standard" three 8' - 12' top-loading wires, it would be interesting to see what top loading coil values (less than needed for a base loading coil) would resonate the antenna at various AM frequencies for given lengths.
I hope this information will be helpful. -- Jason
I just found an interesting indoor 160 meter attic antenna that should work just as well for Part 15 AM: http://www.qsl.net/g3pto/roofant.html
As it is longer than 3 meters (and thus I'd ONLY use it during severe storms or other emergencies to keep a Part 15 AM station on the air), it could be electrically shortened for use with a Part 15 AM transmitter's stock "short antenna" matching network by adding a variable capacitor in series between the transmitter's antenna terminal and the antenna wire.
This antenna is a folded vertical with a top-mounted loading coil and a wire "fan" top-loading capacitance hat connected to the *lower* end of the loading coil. Since the antenna is folded, the loading coil is actually at a low height and is easy to gain access to for fine-tuning.
Using the designer's "standard" three 8' - 12' top-loading wires, it would be interesting to see what top loading coil values (less than needed for a base loading coil) would resonate the antenna at various AM frequencies for given lengths.
I hope this information will be helpful. -- Jason