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Small HF Antennas NNN0OAA
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Aluminum plates separated by .063' glass. 4-1/2' x 4-1/2' and .063' glass (K = 8, 300 V/mil) ... Ted Hart, W5QJR ' ... Ted Hart, regarding AM broadcast version ... – PowerPoint PPT presentation
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Title: Small HF Antennas NNN0OAA
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Small HF AntennasNNN0OAA
- Magnetic Loops
- Crossed-Field (CFA)
- E-H (STAR)
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Magnetic Loops
- Not magic
- Keep losses low
- Capacitor challenges
- Low loss
- High voltage
- High capacitance value
- Remotely variable
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Capacitor Solution 1
- Dielectric loaded variable capacitor
- Jef Verborgt, SWL
- http//www.antennex.com/hws/ws0302/varcap.html
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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
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Capacitor Solution 3
- Glass dielectric (K8)
- Art Heft, W2BRI
- http//www.standpipe.com/w2bri/article1.htm
- Electric screwdriver
- Nylon threaded rod drive
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Capacitor Solution 3a
- Glass dielectric (K8)
- Art Heft, W2BRI
- http//www.standpipe.com/w2bri/article1.htm
- Electric screwdriver
- Nylon threaded rod drive
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Capacitor Solution 4
- IntegratedCapacitor
http//www.g4hjw.demon.co.uk/magloops.htm, Bernie
Wright
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Crossed Field Antenna E-H Origin?
http//www.geocities.com/vk2edb/CFA.htm
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Crossed-Field AntennaMaurice Hately, GM3HAT
andFathi Kabbary
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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
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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.
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E-H AntennaSTAR configuration
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E-H AntennaSTAR configuration
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E-H Antenna STAR configuration
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E-H AntennaSTAR configuration
Choke See http//www.qsl.net/vk5br/EHTraps.htm
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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
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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
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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
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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
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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
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