Modifications by Joe Gurr

draft

Vern Klein, 9 September 2000 Forum.

I guess we have to remember that what Joe Gurr had to say in his communications with Fred Goerner was all relative to the way the radio equipment was when he last knew of it in Burbank.

Gurr describes his first encounter with the radio equipment on the Electra. He says they had just flown in from New York with the radio receiver not working and he had somehow been suggested as the person who could fix it. Amelia and Putnam were frantic that radio equipment installed by so prestigious an outfit as Bell Labs. had failed. It seems to me that would be the Western Electric receiver.

It took a while for him to find the receiver under the co-pilot’s seat. The antenna lead was laying there not connected. When Gurr connected the lead, the receiver came to life. In the eyes of Amelia and Palmer, he had performed a miracle. He points out that people with radio experience were not easy to find in those days.

Of course, Gurr talks some about improvising to give Amelia some 500 kc transmitting capability without using a trailing-wire antenna. Nobody used voice on 500 kc. It was regarded as strictly CW.

Gurr says he tried to catch Amelia long enough to get her checked out on the use of the radio equipment, especially the direction finder, but had little success. Harry Manning had the operation down quite well and they would have time to work with it en route.

"Harry and I covered such things as ambiguity of bearings and flying triangular courses in order to obtain a proper signal source direction." This suggests that there was no thought of a "sensing antenna" to resolve the ambiguity.

On a trial flight out to about 400 miles, Gurr operated the radio equipment while other checks of the aircraft were being done. Radio performance was not good at that distance but got better as they got closer on the way back.

"I was able to take bearings on broadcast stations using the belly antenna, and then switching over to the loop." Note that he says "switching over" not "switching in." I think he used the belly antenna only to get a station tuned in with that more efficient antenna, then "switched over" to the loop to take a bearing -- an ambiguous bearing except that he knew the station was up ahead, not behind.

To me, this suggests that the belly antenna was the receiving antenna and the "V" on top was the transmitting antenna. The T/R relay in the transmitter was not involved and the transmitter could have been heard by the receiver -- if it was not totally "blocked" by the strong signal.

From Ric Gillespie:

Good work Vern, and a strong argument for an antenna set up that matches the antenna loss at Lae with the problems encountered at Howland. ...

It looks, to me, increasingly like Earhart removed the Hooven Radio Compass, which entailed a separate receiver and a sense antenna, and replaced it with the new Bendix loop and coupler which used the existing WE20B receiver and did not employ a sense antenna. The belly antenna was the receiving antenna. When it was lost on takeoff at Lae, Earhart lost her ability to receive until the one brief moment when she "switched over" to the loop and heard the "A"s on 7500. She then switched back to the missing belly antenna and again heard nothing.

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Details in letter to Goerner?

May 1982 letter to Fred Goerner: "I improvised a loading coil and resonated the top antenna system."

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Mike Everette, 7 September 2000 Forum.

Joe Gurr could have very easily made the necessary mods to the radio to jumper the switch function and therefore keep the radio in "Phone" mode. But! Here is a reason why he would NOT have done so, and one that raises credibility issues.

Gurr was trying to "help" AE (yeah, right)preserve her transmitting capability on 500 KHz, by reconfiguring the dorsal antenna to serve on 500 instead of using the much more efficient trailing wire. AE apparently wanted the trailing wire removed, and radio operation simplified, after Harry Manning bolted from the second flight attempt... Manning was to have been the radio operator, and one of his jobs would be to manually reel out and in the trailing wire (as well as to throw the antenna selector switch, located in the aft section).

So, AE knew (we believe) that she needed to preserve the 500 KHz capability. In those days, 500, or "600-meters" (wave length) was the only emergency universally guarded by ships.... and she would be over water quite a bit.

NOBODY used voice on 500! It was then, and continued so until the mid 90s when the regulation requiring ships to guard it was phased out, a CW frequency only. Even Joe Gurr would have known this. He would have come on very strong to AE, I think, about this and the necessity for keeping her CW key.

No one monitoring 500 would have been listening for/expecting a voice signal on 500.

HOWEVER, was AE so strongheaded that she disdained all Gurr’s (and others) expert advice? Could have been. Very likely. ("I don’t care...")

If Joe Gurr had that key I for one would like to know what happened to it. What happened to Gurr’s estate? Did he have heirs? Or was the contents of his house trashed, like I saw happen to the stuff of a recently deceased old time Ham in Durham, NC last month? Wonder if that key has ever turned up at a Hamfest someplace? Wonder if the person who has it now is aware of its origin and significance (and value)?

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