Sorry Jaxie, I'm not playing your game. I'm sure you stayed up all night
reading up on this, while I haven't used RDF in about 20 years. And what bluff
are your calling? Everything I knew about RDF came from the Ray-Jeff manual,
maybe 8 pages.

The simple fact is that RDF was the common way for near-shore cruisers to
navigate 30-40 years ago. Thousands of Ray-Jeff and Benmar RDF units were sold,
and almost any boat that ventured out in the fog had one. When you cruised a
region that has more than a 50% chance of fog daily it would be crazy not to.

You're right that RDF is not as accurate as GPS, and that there are a variety of
errors possible, espcially at sunrise, sunset, periods of sunspots, etc. And
comercial stations with inland towers could be misleading from "shoreline
affect." I'm sure you've googled up a whole list of problems, especially those
of concern to aircraft that need longer range navigation. (I'm sure that's what
going on here - you learned that simple RDF is not good for long range aircraft
nav, you then assume it can't work for small boats.)

However, in practice it was not necessary to worry about this. When you're
crossing the Gulf of Maine planning a landfall at Criehaven, it was reassuring
to hear the beacon on Matinicus (two miles away). The error is meaningless,
since it goes away as you approach. (And you can feel the foghorn if you get
within a mile!) RDF wasn't used much for narrow channels or other close in
work; it was used for approaches from offshore, where there is no other
reference.

So what's your alternative, jaxie? You've claimed many times dead reckoning is
worthless. On an overnight crossing you could easily find a DR uncertainty of
20 miles, more if the helm was sloppy. An RDF fix could reduce the uncertainty
to 5 miles or less. Or it could give you a target to home in on. So what would
you do? I think you would turn back!

BTW, from the latest Bowditch: "In general, good radio bearings should not be in
error by more than two or three degrees for distances under 150 nautical miles."
As I've said, I didn't expect it to be that good, and the way we used it it
didn't matter if it was much worse.





"JAXAshby" wrote in message
...
okay, jeffies. you are trying to tell us you really do know something about
RDF.

so let's call your bluff.

Tell us -- if you can -- just RDF equipment pointing at some radio tower many
miles away is different from a magnetic compass pointing at some lighthouse a
mile away.

Address -- if you can -- the difference in accuracy (be specific as to degree
of uncertainty) between close at hand visional sighting and far away
auditory/cheap volt meter fixing, each system using much the same mechanical
measuring tools.

we will wait for your explanation, jeffies. particualary that "two degrees"
stuff.

jeffies, it never ceases to amaze me how ignorant you are AND how you can't
even seem to realize it.

So with one RDF signal, and a chart, you have a "Line Of Position" or LOP.
Add
in any other piece of information, like a depth contour, and you have a Fix.
Its called "piloting," jaxie, you should learn how to do it some time.

Clearly, if you had learned a few basics like this you would not have been
tempted to "turn back" at Hatteras even though you had a boat full of
electronics.



"JAXAshby" wrote in message
...
obviously, jeffies, you don't understand English. try again.

RDF tell from direction the signal came from. That is all.

And it doesn't do it all that well.

now, TRY AGAIN, and don't be so stupid this time.

RDF tells you where -- and ONLY where -- a particular signal came from.

Sorry jax, I guess you don't know how it works. The chart or book tells
you
where it comes from. The RDF tells you where that is relative to a boat.
Its
called an "LOP." They'll tell you about it in the Power Squadron course