Topband: Long Path Direction!]

[Chuck Hutton]

Hi Tom:


One study never proves anything, in particular when there is extrapolation
(MW > 160 m) involved. We certainly agree there.

Now we have to agree on what is "accurate enough". The military would not
use a single loop system for DF'ing of military targets; their needs are
extreme. Amateurs would want much less accuracy - perhaps for the types of
drastic bearing shifts we are curious about, a 10 degree accuracy would be
fine.

I get the feeling you don't believe DF can be done with any usefullness on
160. You might be right and you might be wrong, but you seem to have tossed
out the study I mentioned assuming it has no validity at all for 160. I
think that's extreme.

And of course a loop won't compete with a Beverage. That's assumed by all
and in particular by me as I had phased arrays of Beverages in multiple
directions for 15 years.


Chuck

-----Original Message-----
From: Tom Rauch [mailto:w8ji at contesting.com] 
Sent: Wednesday, March 31, 2004 5:47 PM
To: CHARLES HUTTON; topband at contesting.com
Subject: Re: Re: Topband: Long Path Direction!]


Hi Chuck,

> A season long study of direction finding on Boston reception of MW
stations
> from Europe, Asia and Africa was once done by an ex-MIT'er using 4' air
core
> loops.

The fact there was a study doesn't prove the instrumentation worked or will
work in this application.

You may find a few articles describing how accurate a loop is for DF'ing
skywave signals, but you won't find very many (if any) DF systems that
require reliable accurate DF'ing of skywave signals that use single loops.

Of course another problem is we won't hear the weak signals anyway on a
single loop, because the directivity is extremely poor and S/N ratio will be
pathetic compared to even a modest directivity Beverage.

I went all through this stuff in the 70's when trying to null LORAN on 160.

73 Tom