Re: [IRCA] Antenna Projects (Crate Loop)

[satya@xxxxxxxxxxxx]

Hi David:

I run my passive loop outputs (Crate Loop, Terk Loop, etc.) through an
MFJ-1020C or Palstar AA30 preselector, both of which have built-in
amplifiers, and it really helps.  In fact, the little Terk Loop and
Palstar AA30 combination gives about the same signal as the Quantum Loop!

I know you can buy stand-alone amplifiers, but the 1020C and AA30 probably
aren't that much more $$$, and you get a lot more funtionality, plus they
have SO-239 connectors ready to go.  In my experience with these two
units, the AA30 delivers more gain to the receiver, but the 1020C tunes
much sharper and therefore helps with adjacent interference and
images/spurs.

Kevin S
Bainbridge Island, WA


> 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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