[Milsurplus] Re: DF-ing & Earhardt/Noonan
Bob Wilder
[email protected]
Sun, 25 May 2003 02:14:22 -0500
In 1954/55 I did a lot of DFing in the central Pacific with good results from less that
100 miles to well over 1000 miles on frequencies in the 5,6,8,11,13,15 MHz ranges. Granted
this was modern DF equipment compared to what AE used and was fairly accurate. Most of the
time the signal being DF'ed was from a very low powered battery operated transmitter in the
less that 1 watt range. Do not ask for details as can not tell you.
At 03:53 PM 5/24/2003 -0700, 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
>_______________________________________________
>Milsurplus mailing list
>[email protected]
>http://mailman.qth.net/mailman/listinfo/milsurplus
>
>
>---
>Incoming mail is certified Virus Free.
>Checked by AVG anti-virus system (http://www.grisoft.com).
>Version: 6.0.483 / Virus Database: 279 - Release Date: 5/19/2003
Bob & Carole Wilder
6032 Idlemoore Court
Theodore, AL 36582-4117
251-653-5274
http://home.earthlink.net/~bwild
Asst State MARS Director- Alabama
AF2HD/AFA2HD
All incoming and outgoing messages are
checked for virus using AVG version 6.0.483
and Virus database 279 updated 05/19/2003
Get your FREE copy at
http://www.grisoft.com
--- StripMime Report -- processed MIME parts ---
multipart/mixed
text/plain (text body -- kept)
The reason this message is shown is because the post was in HTML
or had an attachment. Attachments are not allowed. To learn how
to post in Plain-Text go to: http://www.expita.com/nomime.html ---