[Lowfer] RX Loop Tuning

Thu, 1 May 2003 11:20:44 -0700

Mike, the big advantage of toroids is the magnetic field is "almost"
entirely contained in the material and much less influenced by things close
to it.  The proper choice of material, core saturation and method of winding
will have large effects regardless of core geometry.

Also, if you and I start with a toroid form of the same size and material
and you wind the same turns in the same way I do......there is a really good
chance that we can get within 5% of "identical" results.  Not so easily done
with other core shapes.  Down side is core saturation is easy to do (and
yields bad results ;-) since there is no air gap in the toroid.

Gary WA6DTX
----- Original Message -----
From: "WE0H" <[email protected]>
To: <[email protected]>
Sent: Thursday, May 01, 2003 10:50 AM
Subject: RE: [Lowfer] RX Loop Tuning

> If a guy were to wind the transformers on a ferrite toroid then would the
> higher frequency signals transfer with less loss???
>
> Mike>WE0H
> http://www.we0h.us/lf
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> On Behalf Of Joseph DiVerdi
> Sent: Thursday, May 01, 2003 12:39 PM
> To: [email protected]
> Subject: Re: [Lowfer] RX Loop Tuning
>
> >Paul,
> >
> >>Using cat 5 wire to bring in the antenna provides one with a certain
> >measure of noise immunity from feedline pick up. It also gives one 3
> >addition pairs of wire to things like motor control.
> >
> >Yes, the twist in the cat 5 line should help in the immunity factor. What
> kind of loss can be expected at say 200kHz for 200ft? One time I tried
using
> twisted cable (not cat 5) for sending a square wave to the loop final and
> found the losses to be high.
> >
> >I'm a bit partial to the flexibility of the RG-59 coax with F connectors
> and use it for all TX and RX Lowfer antenna connections. From one of the
> Hams fests I ended up with a ton of free F connectors and male-male
> connectors (which also work nicely as panel mounted connectors) Very easy
to
> try out any new antenna ideas, make quick line extensions, burry the line
> where required, leave it lying on the ground in the woods for months,
etc -
> and the line is very low in loss, including 185k square wave transport.
> >
> >Thanks for the input.
> >
> >Bill
>
> Dear Bill,
>
> I've done a bit of experimenting with low-cost wire to convey low-level
> signals from an active antenna to separately located workshop receiver.
I'm
> interested in lower frequencies (10-100kHz) and toyed around with
> four-conductor telephone-grade wire. The results can be seen at
> http://xtrsystems.com/vlf/transmission_line_test .
>
> I found that the driving and terminating the cable impedances affected the
> loss characteristics dramatically. The limiting factor in my test was the
> high frequency performance of the transformers.
>
> Best regards,
> Joseph
>
> --
> Joseph A. DiVerdi, Ph.D., M.B.A.
> http://xtrsystems.com/           970.980.5868 (voice)
> PGP Key ID: 0xD50A9E33
>
>
>
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