Small HF Antennas NNN0OAA Magnetic Loops Crossed-Field (CFA) E-H (“STAR”)

Magnetic Loops Not magic Keep losses low Capacitor challenges Low loss High voltage High capacitance value Remotely variable

Capacitor Solution #1 “Dielectric loaded” variable capacitor Jef Verborgt, SWL http://www.antennex.com/hws/ws0302/varcap.html

Capacitor Solution #2 From ARRL Antenna Book Richard Plasencia, W0RPV Aluminum plates separated by .063” glass 4-1/2” x 4-1/2” and .063” glass (K = 8, 300 V/mil) 16 to 542 pF @ 12,000 volts 300 V/mil x 63 mils = 18,900 V .224 x 8 x (4.5” x 4.5”)/.063” = 576 pF

Capacitor Solution #3 Glass dielectric (K=8) Art Heft, W2BRI http://www.standpipe.com/w2bri/article1.htm Electric screwdriver Nylon threaded rod drive

Capacitor Solution #3a Glass dielectric (K=8) Art Heft, W2BRI http://www.standpipe.com/w2bri/article1.htm Electric screwdriver Nylon threaded rod drive

Capacitor Solution #4 Integrated Capacitor http://www.g4hjw.demon.co.uk/magloops.htm, Bernie Wright

Crossed Field Antenna E-H Origin? http://www.geocities.com/vk2edb/CFA.htm

Crossed-Field Antenna Maurice Hately, GM3HAT and Fathi Kabbary

Does the CFA work? Egypt Australia Amateurs VK2EDB on 20 Meters San Remo (Italy) AM broadcast, 6 meters tall Supressed unwanted sky wave A viable alternative (for AM broadcast) to the driven mast antenna

E-H Antennas Ted Hart, W5QJR “For more than 120 years all antennas have been Hertz antennas, except the Crossed Field Antenna. In the future all antennas will be EH Antennas.”

E-H Antenna STAR configuration

E-H Antenna STAR configuration

E-H Antenna STAR configuration

E-H Antenna STAR configuration Choke: See http://www.qsl.net/vk5br/EHTraps.htm

How does it work? Synthesizes EM wave … or … Common mode current on coax 5%? 11%? or more? See: http://www.qsl.net/vk5br/EHLongPower.htm Lloyd Butler VK5BR

Evaluations Ted Hart, regarding AM broadcast version Few dB > than ¼ wave vertical with 120 radials, near field Steve Katz, WB2WIK/6 On air: -20 dB vs. roof-top vertical On air: -20 to –35 dB vs. beam Anechoic chamber: -20 to –22 dB vs. ½ wave dipole Adam MacDonald, N1GX (and WA1ZEB), 3/2003 Compass Rose (near Edwards AFB) -28 dB (zero length coax) Significant radiation from coax Desert site, south of California City, CA H R Henly, G3IHR The 20m and 40m versions were tested. The antennas both faired well compared to a 12AVQ and a G5RV when operated under similar conditions, i.e. at a similar height and position with relation to surrounding objects

E-H at NNN0OAA? So far … maybe –20 dB Compared to semi-indoor inverted-L 70' indoor horizontal segment at 18 feet distorted external vertical feed 20 feet long 8’ ground rod, 80’ and 95’ radial SGC230 autotuner EH on deck railing at 10 feet EH in basement 22” off floor EH in basement on floor Two-way contacts were made

Suggestions Magnetic Loop CFA E-H Throw a wire out the window Build it … correctly! CFA Wait … watch the debate, litigation, etc. E-H Build one for FUN and follow the “soap opera” at http://groups.yahoo.com/group/eh-antenna/ SWR meter (a must), FS meter, SWR analyzer Throw a wire out the window

URLs N1GX (E-H) “Compass” N1GX (E-H) “Desert” KB1EGI (E-H) “Pspice” http://home.earthlink.net/~calvinf15/_technical/EH_antenna_test_report.pdf N1GX (E-H) “Desert” http://home.earthlink.net/~calvinf15/_technical/EH_antenna_test_report_2.pdf KB1EGI (E-H) “Pspice” http://www.antennex.com/hws/ws1201/theeh.html Bernie Wright (Magnetic Loops) http://www.g4hjw.demon.co.uk/magloops.htm