[Milsurplus] Re: DF-ing & Earhardt/Noonan

Sat, 24 May 2003 19:17:58 -0400

GA All,
What I have discovered from a good deal of reading about this flight is that the final transmissions from the aircraft were mainly concerned with the "sun line" I believe it was 103/283 degrees which Noonan had apparently shot, and the aircraft was doing a racetrack pattern on this sun line. OK, a sun line only gives you one line on the chart, and they were probably trying to cross it with a DF line, but something prevented them from getting a null. I wonder if by this point, some degree of panic and clouded thinking had set in, and they were aimlessly making course changes, not kept track of time/airspeed, had lost all their DR info, and the info which they had, was, of course, no good for navigation, since they had basically forgotten where they had been, a necessary part of DR nav. 
The other item, which I wish someone would enlighten me on is why the SHIP to which they were talking couldn't get a good DF off their transmissions.   It seems that would have been the easiest way to do this, let the ship cut a line, and give them a steer from that point, albeit you wouldn't have distance info, you would at least have known where Howland was, the general direction to the aircraft, and could have given them a rough heading to steer, which could have been refined with a series of DF cuts taken at regular intervals, thereby determining the groundspeed and actual position.

It is easy though, to Quarterback on Monday AM

73 de Greg 

Strange. It's still a 
mystery, and if you figure anything out about it, you will
have made a definite contribution to (maybe) understanding
what happened near Howland.

Hue Miller wrote:

>----- Original Message ----- 
>From: "Al Klase" <[email protected]>
>
>  
>
>>Hue,
>>
>>Interesting info about the 7500KC DF.  At that freq. you 
>>could have a really strong skywave hitting you nearly 
>>vertically when you were within 100 miles or so of the TX.
>>Hence no null.
>>    
>>
>
>I think it depends on how the skywave and direct wave combine.
>I have done a very little bit of DFing on 49 meter BC stations,
>and you can get a null, even from stations MUCH farther than
>100 mi. out, but.....it gets really impossible if propagation is
>unstable, moreso even around sunrise/ sunset, when it's 
>unusable. I have a manual for the SCR-504 ( i think it is....)
>"suitcase DF", serendipitously found in an antique store by
>itself, and i was very happy to pay the $15 price,  believe
>me, anyway this manual talks about the same thing, the
>sunrise/ sunset problem.
>
>Also a note that AE/FN had flown around the Lae, Niu
>Guinea airfield a day or so before, trying to get a null on
>the airfield's 6 Mcs signal, but couldn't. AE bagged that 
>trial, saying that maybe the airfield signal was too strong,
>but that sounds not right, don't it? I mean, she could
>just have flown out a few miles. Strange. It's still a 
>mystery, and if you figure anything out about it, you will
>have made a definite contribution to (maybe) understanding
>what happened near Howland.
>
>Maybe they just didn't have enuff experience with this.
>I found it could be very frustrating to try to get a null
>sometimes, as the null depth might constantly change,
>but if you were persistent, didn't give up, you could
>often tell the general direction of the null within say,
>just guessing here, 15 degrees. IF they had gotten
>this, then switched to "DIRECTION" on the DU,
>to engage the sense circuit, they could have gotten
>the right direction too, which would have helped them
>at least fly in the right direction and general bearing,
>instead of wondering if they were going / coming.
>Hue
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>  
>

-- 
"All that is necessary for the triumph of evil is that good men do nothing."
                                                   --Edmund Burke

Greg Moore NNN0BVN PA
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