Small HF Antennas NNN0OAA

1
Small HF AntennasNNN0OAA

• Magnetic Loops
• Crossed-Field (CFA)
• E-H (STAR)

2
Magnetic Loops

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

3
Capacitor Solution 1

• Dielectric loaded variable capacitor
• Jef Verborgt, SWL
• http//www.antennex.com/hws/ws0302/varcap.html

4
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 _at_ 12,000 volts
• 300 V/mil x 63 mils 18,900 V
• .224 x 8 x (4.5 x 4.5)/.063 576 pF

5
Capacitor Solution 3

• Glass dielectric (K8)
• Art Heft, W2BRI
• http//www.standpipe.com/w2bri/article1.htm
• Electric screwdriver
• Nylon threaded rod drive

6
Capacitor Solution 3a

• Glass dielectric (K8)
• Art Heft, W2BRI
• http//www.standpipe.com/w2bri/article1.htm
• Electric screwdriver
• Nylon threaded rod drive

7
Capacitor Solution 4

• IntegratedCapacitor

http//www.g4hjw.demon.co.uk/magloops.htm, Bernie
Wright
8
Crossed Field Antenna E-H Origin?
http//www.geocities.com/vk2edb/CFA.htm
9
Crossed-Field AntennaMaurice Hately, GM3HAT
andFathi Kabbary
10
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

11
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.
12
E-H AntennaSTAR configuration
13
E-H AntennaSTAR configuration
14
E-H Antenna STAR configuration
15
E-H AntennaSTAR configuration
Choke See http//www.qsl.net/vk5br/EHTraps.htm
16
How does it work?

• Synthesizes EM wave or
• Common mode current on coax
• 5? 11? or more?
• See http//www.qsl.net/vk5br/EHLongPower.htmLloy
  d Butler VK5BR

17
Evaluations

• Ted Hart, regarding AM broadcast version
• Few dB gt 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

18
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

19
Suggestions

• Magnetic Loop
• 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

20
URLs

• N1GX (E-H) Compass
• 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