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The Hopes, Plans and Misadventures of the 1999 4M7X DXpedition

43 Verticals on the Beach. The Hopes, Plans and Misadventures of the 1999 4M7X DXpedition. By Dean Straw, N6BV Visalia International DX Convention, April 27, 2002. Flush with our 6Y2A CQWW CW Multi-Multi victory in 1998, Team Vertical set out to beat our own record in 1999. 6Y2A, Jamaica.

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The Hopes, Plans and Misadventures of the 1999 4M7X DXpedition

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  1. 43 Verticals on the Beach The Hopes, Plans and Misadventures of the 1999 4M7X DXpedition By Dean Straw, N6BV Visalia International DX Convention, April 27, 2002

  2. Flush with our 6Y2A CQWW CW Multi-Multi victory in 1998, Team Vertical set out to beat our own record in 1999... 6Y2A, Jamaica

  3. We had almost 18,000 QSOs in 1998 from 6Y2A — But a lot were with the USA, worth only 2 points in the CQWW contest.

  4. To Beat the 6Y2A Record • We had to move where: • European, USA and Japanese QSOs would each be worth 3 points. • Logistics wouldn’t be overwhelming for Team Vertical — That pretty much left out Africa. • Luckily, some team members had extensive experience in Venezuela.

  5. It’s 1000 Miles from 6Y2A to 4M7X, but it’s Three-Point Territory

  6. The Advantages of Verticals Over Saltwater -- the 6Y2A Experience • Low elevation angles are critical, especially on the lower bands.

  7. The Advantages of Verticals Over Saltwater -- the 6Y2A Experience • Higher angles are important also.

  8. Our Goal: 2 dB More Gain on Each HF Band, 10 to 80 Meters, Compared to 6Y2A Antennas • We have learned that each additional 2 dB opens up another layer of callers.

  9. Covering All Azimuths • The 6Y2A arrays were fixed in azimuth. • At 4M7X, we needed steerable vertical arrays with more gain. • On 80 and 40 meters we chose Four-Square arrays, using Comtek boxes. • On 20/15/10 meters we wanted even more gain than a Four-Square.

  10. The “Cross-5” Array Europe Disabled Director 0.2  0.2  Common Driven Element 0.2  0.2  Disabled Reflector Symmetrical array, with a common Driven Element. The Cross-5 uses half-wave vertical dipoles (HVDs).

  11. Cross-5 Switching from N6BV Engineering Notebook

  12. Cross-5 Truth Table from N6BV Engineering Notebook

  13. Cross-5 Array • Peak Gain over saltwater is 12.3 dBi. • F/R is modest: 11dB, which is OK. • Covers all needed elevation angles well.

  14. We Compete with Stations Using Stacked Horizontal Yagis on the 20/15/10-Meter Bands • Gain of 15-16 dBi for stacks is common. • Cross-5 alone won’t be competitive, except at really low elevation angles. • Vertically stacking vertical arrays is physically very difficult!

  15. What to do? • Stack ‘em! Side-by-side with “Sidecars.” (When pointing to JA, the Europe Sidecar is out of circuit.) 1  1  JA “Sidecar” Cross-5 Europe “Sidecar” Now the stacked Gain is a very respectable 15.2 dBi. We had 11 elements each on 20, 15 and 10 meters.

  16. Aiming the Antennas Japan Europe USA

  17. Feeding Cross-5 and Sidecars JA Sidecar Cross-5 EU Sidecar WX0B Stackmatch Phasing Line Phasing Line RF Azimuth Control

  18. A Very Narrow Pattern Results • Combined Cross-5 + Sidecar has a 35° 3-dB Beamwidth — We called this a “Superbeam.”

  19. Oh, by the Way... • When the azimuths to Europe and Japan aren’t exactly 90° apart, you’ve got to fiddle with the phasing lines to make them aim in exactly the right directions. (Remember how narrow they are?) • We leave that exercise to the student.

  20. Other Nearby Radiators Affect the Pattern Some Cross-5 affected by Sidecars — Note that this happens for almost all ham installations with nearby arrays.

  21. Detailed Patterns to Europe/Africa

  22. Detailed Patterns to USA/Japan

  23. We Had Some Killer Antennas on Paper Now we had to find a great place to put them!

  24. We OriginallyPlanned on Operating from the Venezuelan Mainland • But the distances from the operating positions to the antennas were > 1000’. • Logistics getting there were difficult. • We didn’t have local friends at the chosen location.

  25. So We Chose a Promising New Location on Coche Island, off Margarita Island • We had local contacts, especially in Customs, and local friends. • A new hotel was being finished at a fantastic radio QTH, on the salt flats. • Coax runs to the antennas would be reasonable.

  26. 4M7X on Coche Island, Venezuela MargaritaIsland Coche Island 4M7X

  27. Local Layout 15 Mult. Antennas 20 10 80 40 160 80 RX 160 RX Margarita ~ 5 miles to the North Coche Island

  28. Getting to Coche Island • SFO to Miami (American Airlines) • Miami to Margarita Island (Aeropostal Airlines) • Margarita to Coche Island (by boat)

  29. A VeryWet Dave & Ralph NT1N K9ZO Hurricane Lenny Creates Hazardous Seas

  30. Uh, Senõr, We Have a Little Problem at the Hotel... • Uh, they didn’t quite finish building it… • And there is no power... • And there are no windows or doors...

  31. Team Vertical Presses On Real Contesters will not be denied! • We hire and transport (at great expense, with a big truck) a 70 kVA diesel generator from the main island. • We rewire the hotel — good thing OSHA wasn’t watching. • We find accommodations at a nearby hotel, full of German tourists.

  32. Electrical Distribution & Antenna Patch Panel No Doors, No Windows, No Wiring... 220 VAC Wiring High Band Shack Low Band Shack Antenna Patch Panel

  33. El Oasis Hotel & Generator Operating Area Goat Guano 70 kVA Diesel Generator

  34. Building the Antennas 20-meter HVDs (Halfwave Vertical Dipoles)

  35. 160-m 2-ElementVertical ArraySame 57’ Elements as 6Y2A 15/40 Mult Yagi Reflector Driven Goat Pen

  36. 80-m Four-Square Vertical ArraySame 37’ Elements as 6Y2A Notice the Cinder-Block Guy Anchors -- These Would Lead to Lots of Problems Later...

  37. 40-m ZR Four-Square ArraySame 15’ Elements as 6Y2A 10 m JA “Sidecar” 40 m Driftwood prop for 160-m radial

  38. 15-m Array and Margarita Island20/15/10-m Arrays Each Had 11 Elements JA Sidecar Cross 5 Eu. Sidecar Relay box, 1of 4 per Cross-5

  39. Flooded Beach, 10-m ArrayYes, That is Indeed Saltwater Vertical Heaven!

  40. Through aVertical Forest, Darkly 160 m 20 m 10 m 20 m 160 m 40 m 10-m Relay Box Notice the salt water

  41. Moon Over the Vertical Patch

  42. 4M7X Antenna Summary Antenna Design Goal: Increase Gain by 2 dB on 10-80 m Compared to 6Y2A 160 m: 2-Ele. 57’ Vertical Array, Fixed on Europe 80 m: 4-Square, 37’ Linear-Loaded Elements, Comtek Box 40 m: 4-Square, 15’ 40-ZR verticals, Comtek Box 20 m: 11 HVD Elements + WX0B StackMatch 15 m: 11 HVD Elements + WX0B StackMatch 10 m: 11 HVD Elements + WX0B StackMatch 43 Vertical Elements for Team Vertical !! Multiplier Antennas: 10/20-m Yagi @ 20’, 15/40-m Yagi @ 20’ Rx: Low dipoles for 160/80 m

  43. 4M7X and Local Crew of El Oasis de Coche

  44. We Ran Into a Few More Problems • We couldn’t find good solid anchors for antenna guy ropes. We used concrete block anchors, to our regret later. • The 40-m station absolutely killed all other bands — even at 5 W output. • Storms brewed up, bad for guy anchors and really bad for lightning bolts. • The goats kept getting out and the “supersonic mosquitos” were amazing.

  45. Troubleshooting 40-m InterferenceLuckily, we had dozens of ferrite chokes 40 m 10 m 10 m K2KW NT1N High Band Control Cables

  46. So, Did the Antennas Work? • They worked very well, while they were vertical. We had outstanding reports from the USA and Europe before the contest started. • Just prior to the opening gun we were pumped! Tired, but pumped.

  47. Some of the Guys... N6BT YV5AMH N6BV Dick

  48. K9ZO YV5EED

  49. W4SO

  50. Lunch at the El Oasis Hotel

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