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Amelia Earhart HF Radio


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7 hours ago, aviatoreb said:

What does a ham talk about on ham radios while flying?  Is it to talk to other airborn hams or is it maybe for better range to land born hams?

I've made contact with a Citation medical flight when I was on the ground once using 520 simplex. He was receiving calls from about 200 miles out.

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11 hours ago, aviatoreb said:

What does a ham talk about on ham radios while flying?  Is it to talk to other airborn hams or is it maybe for better range to land born hams?

Excellent question. Mostly we talk about equipment used and flight conditions. For most hams talking to an airborne ham is a novelty. When out of cell phone range I contact a ham to convey by phone my ETA to friends or family at the airport. I found it very useful on my way to TJMZ from KFXE. At 14.300 Mhz there is a ham/marine net that provides assistance to private vessels and planes over water. Volmets also provide HF weather info for when out of range of VHF https://en.wikipedia.org/wiki/VOLMET.

KP4DAC

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16 hours ago, BCrystal said:

Brian Lloyd, WB6RQN, will be flying Round The World in his Mooney M20K 231 in June-July 2017 for Project Amelia Earhart, 80th Anniversary 1937-2017. The flight traces the historic equatorial route, starting on the same date (June 1st) and ending up at 2017 EAA AirVenture in Oshkosh Wisconsin USA on Monday 24 July.

A Micom 3 HF SSB ALE radio has been installed in the Mooney with a new under-fuselage "belly" HF antenna with ATU. Brian Lloyd designed the system and antenna; he will utilize HF radio for ATC as well as ham radio. The Micom 3 radio is a commercial 125 Watt HF transceiver which covers all the aeronautical HF and amateur radio HF frequencies from 1.6 MHz to 30 MHz (and also receives 100 kHz to 30 MHz). It has a main radio unit mounted in the aft avionics bay, and a control head mounted in the main cockpit control panel, which has been custom-made to fit.

Since open source HF antenna design information is scarce for Mooney aircraft, I'm posting some details here for those who are interested. The belly antenna is slightly offset to the left side of the fuselage. The antenna installation utilized Dayton-Granger parts:

  • 10 inch aluminum antenna strut with insulated hole
  • 10 inch non-insulated aluminum antenna strut 
  • Antenna insulator angled feed thru
  • Antenna insulated tensioner
  • Insulated antenna wire

Computer modeling shows that the wire is self-resonant at about 17.7 MHz, and the outer aircraft skin itself is resonant at radio frequencies of about 6 MHz and 12 MHz. The SGC Antenna Tuning Unit (ATU) is required to match a capacitive reactance load with an impedance of less than 10 ohms on most HF frequencies. Here are some images showing the HF antenna system during installation, and some results of antenna computer modeling.

Mooney_HF_Belly_Antenna_Geometry_Model2a.jpg

N916BL_Mooney_HF_Belly_Antenna_Brian_Lloyd_1024.jpg

MooneyM20_ALE_HF_Antenna_System2017_05A_1024.jpg

Mooney_HF_Belly_Antenna_13MHz_Pattern_1a.jpg

Project_Amelia_Earhart_Cover_Image2_820x360.jpg

On my HF setup the antenna runs from the vertical fin top to the cabin top. This is the most popular set up for airborne HF antenna. It allows for communication on the ground like when getting an Oceanic clearance at a remote place and for testing and tuning your HF equipment on the ground. 

706 in Mooney4.pdf

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