Re: [IRCA] Antenna Projects (Crate Loop)

["HASCALL, DAVID CIV DFAS" <DAVID.HASCALL@xxxxxxxx>]

Thanks Chris:

I will archive your email.  The only true "communication receivers" that
I have are a 20 year old RS DX-400 and a Grundig S-350.  Both have built
in ferrite bar antennas, so that complicates things somewhat in terms of
directionality.  Also both are perfectly setup for using the sense coil
setup.  The RS has screw terminals and the Grundig has spring loaded
ones.  I had an old Sanserino loop and right out of the little amplifier
was more of the same type of wire that was used in the loop - one side
to A1 and the other to A2 or whatever the DX-400 says on the back.  So,
I had no connecting cable, of another material at all.  It worked good
and as I had said before I added something like 7 new ones during the
day, the first day and that was at high noon with no skywave.  So I'm
confident that the Crate could be similar but would a small amp kick
things up a bit?


73,
Dave in Indy

-----Original Message-----
From: Chris Knight [mailto:chris@xxxxxxxxxxxxxxx] 
Sent: Friday, January 02, 2009 4:41 PM
To: HASCALL, DAVID CIV DFAS; irca@xxxxxxxxxxxxxxxx
Subject: RE: Antenna Projects (Crate Loop)

Hi Dave,

My strategy for the pickup loop "sense coil" will be a wire loop of
one-turn
(possibly two turns like Kevin did) around the crate. For the connecting
cable, I plan on using a small length of 300-ohm TV lead-in wire (like
this,
but smaller (10 feet)
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=tv%20lead%20in%20
wire
&origkw=tv%20lead%20in%20wire&sr=1 ). The pickup loop can be the same
kind
of wire you used to string around the crate. After winding the pickup
loop,
strip about an inch of insulation off each end of the pickup loop. Next,
take one end of the TV lead-in wire and strip it back about an inch
exposing
both wires. Connect both sides of the pickup loop to the each of the 2
wires
on the end of the TV lead-in wire, one for one. Soldering these together
is
a good idea. Then strip an inch of insulation off the other side of the
TV
lead in wire, exposing the two wires on that end. That side will plug
into
your radio (Drake R8 in my case). One side will plug into the 500-ohm
antenna terminal and the other side will plug into the Ground terminal.
It's
a good idea to tin the ends going into the radio with a little bit of
solder, especially since each of the two conductors consists of strands.

What radio do you have? If your radio doesn't have plug-in antenna
terminals
like mine, you will need to use 50-ohm coaxial cable instead of TV
lead-in.
The only problem with that is the impedance mismatch, which even occurs
with
the TV lead-in, but might not be enough to worry about. The tuned loop
which
is a tank circuit has very high impedance. Matching using a toroidal
inductor is possible. Has anyone tried that with success?

Hopefully this explanation wasn't too confusing. If you have any more
questions, please let me know.

73 and good luck!

Chris

-----Original Message-----
From: HASCALL, DAVID CIV DFAS [mailto:DAVID.HASCALL@xxxxxxxx]
Sent: Friday, January 02, 2009 2:03 PM
To: irca@xxxxxxxxxxxxxxxx; chris@xxxxxxxxxxxxxxx
Subject: RE: Antenna Projects (Crate Loop)


Hi Chris - I had asked about "direct coupling" of the Crate Loop to a
receiver's antenna terminals and Kevin graciously replied and mentioned
it needing a "sense coil" (as you also noted).  He stated that he may
have to try that in the future.  This seems to be one of the easiest
loop plans that I have seen and maybe there is hope for me - a "tech
dummy."

73,
Dave in Indy


------------------------------

Message: 5
Date: Fri, 2 Jan 2009 13:34:28 -0700
From: "Chris Knight" <chris@xxxxxxxxxxxxxxx>
Subject: [IRCA] Antenna Projects
To: "Mailing list for the International Radio Club of America"
	<irca@xxxxxxxxxxxxxxxx>
Message-ID: <MDELJBGOEGKHBKJNEBBFKEFOCAAA.chris@xxxxxxxxxxxxxxx>
Content-Type: text/plain;	charset="iso-8859-1"

The Crate Loop looks like a great project and I'm going to start
building
one this weekend to use with a Sony ICF-SW7600GR (light, but not
ultra-light) and perhaps with the Drake R8 (using a pick-up turn of
wire).
The only problem here is the computer hash (5 computers at this QTH).

The helically-wound vertical posted by Craig Healy may be the answer to
the
computer noise. The plan is to build a scaled-down version to go next to
the
computer in the shack as a noise sense antenna and attempt to phase out
some
of the hash.

Thanks guys for the great ideas/designs and for posting them! 73.

Chris Knight
Fort Lupton, CO



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