[Lowfer] Wm Beacon "Current" Question

[Mitch Powell]

Neil :  John has the right idea.....I think the slash after htm is the
proble
should be
http://www.w1tag.com/RFA.htm
Just checked okay.

I still do just as John suggested though  :-)
Mitch

On Mon, Dec 1, 2014 at 9:42 AM, Neil Klagge <lowfer.nklagge at gmail.com>
wrote:

> Hi Mitch. You sent a link that does not work for me.
> You said, " I have had great results
> using the rf ammeters I have built - for various power ( current ) levels
> as shown on John's website, RFAmmeters for LF.  They are very simple to
> build - calibrate very easily and never seem to change. The link is:
> http://www.w1tag.com/RFA.htm/
>
> I am very interested in that article.
> Neil, XSV
>
> w0yse, wg2xsv,now in Vancouver WA
> CN85rq
>
> On Sat, Nov 29, 2014 at 11:41 AM, Mitch Powell <ve3ot.mp at gmail.com> wrote:
>
> > Mike:
> > This may be a repeat of an earlier email - but I have had great results
> > using the rf ammeters I have built - for various power ( current ) levels
> > as shown on John's website, RFAmmeters for LF.  They are very simple to
> > build - calibrate very easily and never seem to change. The link is:
> > http://www.w1tag.com/RFA.htm/
> >
> > Also - first copy of WM this Saturday morning... attached.
> > 73
> > Mitch
> >
> >
> > On Thu, Nov 27, 2014 at 12:18 PM, JD <listread at lwca.org> wrote:
> >
> > > Mike, keep in mind that a current meter for a loop is designed to
> measure
> > > higher current levels because an electrically small loop offers a very
> > low
> > > resistance if constructed carefully.  A short vertical has inherently
> > high
> > > capacitive reactance, which you neutralize with the loading coil, plus
> > > resistive losses in that coil, the ground system, and nearby
> > environmental
> > > factors.
> > >
> > > Thus, from the P= I^2 * R relationship, we see that for the same power
> > > level, current in a high impedance circuit must be lower than it would
> be
> > > in
> > > a low impedance circuit.  That's why the meter deisgned for the loop
> > barely
> > > responds in the case of the vertical.
> > >
> > > LowFER vertical antennas vary widely in their resistive component due
> to
> > > local soil conductivity and coil construction variations.  Most reports
> > > I've
> > > seen on successful beacons indicate measured RF currents typically in
> the
> > > range of 120-250 mA.  It's hard to get loss factors low enough to
> exceed
> > > 250
> > > mA for 1 watt.  Much lower than 120 mA, and the beacon may not get out
> > very
> > > well...although nowadays with slow modes like QRSS, that's less of a
> > > problem
> > > than it would have been 15 years ago.
> > >
> > > John
> > > ______________________________________________________________
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