[Lowfer] Ferrite Rod [Lowfe Worthwhile going to Shielded loop?r]

Tue, 28 Oct 2003 11:11:56 -0500

Hey Mike,

Well awhile back I found them at a local fleamarket.
They are actually about 10" to 12" long each, and I have 3 in series, glued
with some old ferrite glue I had from back in TV repair days.
The rods were about 3/4" in dia with a hole in the middle..  I used a piece
of threaded rod in the middle of the stack to hold them together while the
glue was setting.  I rolled the assembly on a flat piec of steel to insue
they wee all concentric.

Ater the glue set, the threaded rod was removed and the center filled with
epoxy for added strength.
Litz windigs were added, and  the whole thing is fitted into a PVC pipe and
sealed with hot glue gun.

I am sorry that I did not buy all the rods the guy had.

PauLC
W1VLF

----- Original Message ----- 
From: "WE0H" <[email protected]>
To: <[email protected]>
Sent: Monday, October 27, 2003 10:23 PM
Subject: RE: [Lowfer] Re: [Lowfe Worthwhile going to Shielded loop?r]

> Hey Paul,
>
> Where did you get the ferrite stick for that big sucker???
>
> Mike>WE0H
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> On Behalf Of paulc
> Sent: Monday, October 27, 2003 1:32 PM
> To: [email protected]
> Subject: [Lowfer] Re: [Lowfe Worthwhile going to Shielded loop?r]
>
> John,
>
> Thanks for lending your experience to the query.
> >From your email
>
>  My only experience with shielded receiving loops has been with small,
> > multi-turn versions. There were no significant reductions in noise, and
> the
> > extra capacitance did narrow the tuning range.
>
> Why do  you suppose that there a common notion that says the shielded loop
> is quieter?
>  Is your loop located far enough from the house that maybe manmade noise
is
> not a problem?
> Perhaps if your only alternative to listen to LF was from an inside the
> house location, the shielded antenna have its desired effect?
> Seems to me Palomar made a shielded loop for table top use.
>
> To some extent it would seem that size doesn't matter....  for loop
antennas
> anyway.  Until the antenna "gain" and system noise figure become greater
> than the noise floor, seems like the smaller antenna doesn't hurt you.
>
> I have a nearly 3 foot long loopstick I could try in the woods sometime.
> Maybe I will do that.  It is tuned for about 160 to 190 Khz
>
> PauLC
> W1VLF
>
> ----- Original Message -----
> From: "John Andrews" <[email protected]>
> To: <[email protected]>
> Sent: Monday, October 27, 2003 2:35 PM
> Subject: Re: [Lowfer] Worthwhile going to Shielded loop?
>
>
> > Paul,
> >
> > My only experience with shielded receiving loops has been with small,
> > multi-turn versions. There were no significant reductions in noise, and
> the
> > extra capacitance did narrow the tuning range.
> >
> > But I haven't played with a larger, single-turn shielded loop. I'd defer
> to
> > Jay's experience on that one. He and I have produced similar signal
> reports
> > with our respective antennas. Mine is unshielded, with 14 turns on a 6
> foot
> > square. The turns are an inch apart. I'd suspect that Jay's antenna
> delivers
> > more signal (+noise) to the preamp, though. I tried my "Ashlock" loop
for
> > receiving on 137 kHz last winter, and found that despite the greater
> signal
> > (+ noise), I wasn't copying anything better than I could with the
smaller
> > loop. It did offer the possibility of eliminating the preamp, though.
> >
> > John A.
>  _______________________________________________
>  _______________________________________________
>
>
>
> _______________________________________________
> From the Lowfer mailing list
> Send messages to: [email protected]
> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer