[Milsurplus] Re: SCR 269 type ADFs vs manual steered loop ADFs

[BOEING377@aol.com]

Having used both manually steered loop DFs and BC 433 and ARN 7 ADFs on=20
commercial fishing boats I can tell you that there is no comparison for=20
usefulness.=A0 The ADF wins hands down every time. Trying to steer and shoot=
 manual DF=20
shots as the vessel yaws in big following seas is a real hassle. Done it, ha=
ted=20
it. If you are shooting a station abeam rather than dead ahead, the angles c=
an=20
change pretty fast as you progress on your track. If its a hassle at 7 knots=
,=20
imagine what it is like in a plane doing 20 times that speed. With an ADF yo=
u=20
just watch the needle and see constant accurate updated bearing information

As a kid I rigged a really crude interface (hey, I was only a kid) between=20
the 2050 thyratron loop motor controllers in the ARN 7 and the boat's autopi=
lot=20
steering motor control.=A0 Essentially it disabled the loop motor and let th=
e=20
boat steer the loop to a null. This allowed an automatically coupled approac=
h to=20
be steered. It wasnt proportional steering with a dead band in the middle,=20
just left right hunting but it worked great. Once a relay stuck and put the=20=
boat=20
in a tight circle messing up all the fishing gear. I never heard the end of=20
it. We were trolling from the SF Lightship to the Farallon Islands, in thick=
=20
fog, coupled to the Island's powerful LF beacon. My dad never really trusted=
 my=20
setup after that and only used it in clear weather. He kept a dead reckoning=
=20
track record and regarded most but not all the surplus stuff as my hobby toy=
s.=20
He did like the ability to shoot bearings on other boats radio transmissions=
=20
(with band 4 of the ARN 7 tweaked to get the 2-3 Mc marine band).

The ARN 7 was ultra reliable.=A0 Used it for 12 years with the only repair=20
being to replace a corroded LP 21 loop, corroded because I never got around=20=
to=20
rigging a loop dehydrator as called for in the manual. New loops were $25 ba=
ck=20
then so no big deal to throw a new one on.=20


--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
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  ---