Radio equipment on NR16020
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Date: Sun, 4 Jun 2006 21:01:18 From: Hue Miller Subject: Re: Howland Island DF
> Anyone seen other correspondence relating to this?. > By the way, the SF Chronicle reported that AE carried two 50 watt > transmitters, and listed her call letters KHAQQ. [ Ibid, p. 200]
Well, they got the callsign right, but the reporter managed to scramble the rest, which was 2 channel 50-watt output. ( And only a fraction of that is radiated; in the horizontal part of the antenna, the radiation is cancelled against the currents in the airframe, so the only radiating part is the vertical rise, which is not a whole lot.) A trailing antenna would have vastly improved her voice communications also, but would have been trickier to tune, because you either have to watch the current meter closely while you reel out the wire, or you have to have an accurately re settable counter on the reel. But that would have been a one time thing, once in the air, and it sure would beat fiddling with direction finder on the shortwave channels, in a race against the clock.
Ric Gillespie, June 21, 2000, Forum.
1. When the airplane was delivered to AE in July 1936 it had a WE 13C transmitter and a WE 20B receiver, the same radios (or so it would seem) that it had when it disappeared. However, there was no dorsal antenna on the airplane at all. There was a belly antenna identical to the one that was apparently lost at Lae with a lead-in that entered the fuselage right under the copilot's seat where the 20B receiver was mounted. The only other antenna on the airplane was a trailing wire that deployed from the extreme tail of the airplane, just under the navigation light. At that time the airplane appears to have no DF capability at all. What, in your opinion, was the function of the belly antenna at that time?
2. Sometime around October 1936 the Hooven Radio Compass was installed. This involved a separate receiver mounted on a fuel tank in the cabin, a dome-shaped antenna on the cabin roof, and another belly antenna that ran parallel to the original belly antenna but on the opposite (port) side of the airplane. The trailing wire in the tail remained unchanged. What, in your opinion, was the function of the new belly antenna? What, in your opinion, was the function of the original (starboard) belly antenna at this time?
3. In mid-February 1937 Earhart flies the airplane to New York to announce her planned World Flight. While she's on the east coast Western Electric installs a new dorsal vee antenna. All the other antennas remain unchanged. What, in your opinion, was the purpose of this antenna?
4. Back in California in late February the trailing wire is moved from the extreme tail to deploy from a mast under the cabin. Right around March 1st comes the big change in DF equipment. Hooven's Radio Compass and it's domed-shaped antenna go away and are replaced by the Bendix loop over the cockpit. The belly antennas -- both port and starboard -- remain unchanged. What, in your opinion, is the function of each of these antennas at this time?
5. The airplane goes to Hawaii, gets wrecked, and comes back to Burbank for repairs. When it come out of the shop several changes are apparent in the antenna set-up.
- the dorsal vee has been lengthened by moving the mast forward.
- the trailing wire is gone.
- the port side belly antenna (that had been added when the Hooven DF was installed) is also gone.
Unchanged are the Bendix loop over the cockpit and the starboard side belly antenna. What, in your opinion, is the function of the belly antenna at this time?
There is no change to the airplane's antenna configuration while it is in Miami or later (until the belly antenna gets knocked off in Lae.)