[Lowfer] WM and MP post dinner shot
Bill Ashlock
ashlockw at hotmail.com
Sat Jan 30 21:55:19 EST 2010
Rick,
The core you describe, below, should be large enough at a 1W power level. I've found that they can even be quite a bit smaller without stealing much of that precious power feeding the loop. Just be sure you don't go below the '4X' rule.
Bill
> From: theumpire at verizon.net
> To: lowfer at mailman.qth.net
> Date: Sat, 30 Jan 2010 03:23:03 +0000
> Subject: Re: [Lowfer] WM and MP post dinner shot
>
> Thats why Im thinking that the core Im using is probably #43 or
> worse.Digi -Key doesnt stock some of the part numbers you mention in the
> article. I picked up a few of what they did have but they were a little
> small. The one Im using is roughly 1.25" O.D. x .75 " I.D. x .625" High. I
> have to keep my eye out for more cores but for now this should do.
>
> 73 and TNX
> Rick
>
>
>
>
>
>
> ----- Original Message -----
> From: "Bill Ashlock" <ashlockw at hotmail.com>
> To: <lowfer at mailman.qth.net>
> Sent: Friday, January 29, 2010 7:06 AM
> Subject: Re: [Lowfer] WM and MP post dinner shot
>
>
> >
> > Rick,
> >
> > So you are very close to my predicted 8 to 1 ratio for #12 loop conductor,
> > right? (24 divided by 3 = 8) If you were using a type 77 core you would
> > find that there is enough inductive reactance to use only 8T on the
> > primary and 1T on the secondary.
> >
> > QED
> >
> > Bill
> >
> >> From: theumpire at verizon.net
> >> To: lowfer at mailman.qth.net
> >> Date: Fri, 29 Jan 2010 04:07:29 +0000
> >> Subject: Re: [Lowfer] WM and MP post dinner shot
> >>
> >> Ok Bill,
> >> I am actually using 24 turns not 20 .The secondary is 3 turns.I
> >> measure
> >> just about 20 volts at the transmitter under keydown and a current of
> >> 50ma
> >> when I peak the trimmer cap.
> >> The loop is 200 ft but measures 40 x 60 .Its #12 wire.
> >> I originally wound the xfrmr with 13 : 2 ratio but the input current was
> >> over 100ma at resonance so I just kept adding turns to get it down to the
> >> 1
> >> watt level.
> >>
> >> Thanks
> >> Rick
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> ----- Original Message -----
> >> From: "Bill Ashlock" <ashlockw at hotmail.com>
> >> To: <lowfer at mailman.qth.net>
> >> Sent: Friday, January 29, 2010 3:17 AM
> >> Subject: Re: [Lowfer] WM and MP post dinner shot
> >>
> >>
> >> >
> >> > Hi again Rick,
> >> >
> >> > Refresh my memory a bit on what your transmitting setup is like.
> >> > Assuming
> >> > you have only one turn on the secondary (a single pass through the
> >> > core) a
> >> > 20 to 1 ratio is too much of an impedance ratio (400 to 1). You may be
> >> > using more than 24v into your final (a Vcc of 24v would represent a
> >> > square
> >> > wave into the coupling xfmr of ~ 23v p-p) or your loop wire may be a
> >> > fair
> >> > amount shorter than 200ft. If you were using 200 ft of #12 house wire,
> >> > like I am, the ratio would be close to 8 to 1. If RG-8 it would be
> >> > approx
> >> > 13 to 1.
> >> >
> >> > You will always experience some current swing when the wind blows and
> >> > your
> >> > loop is supported by the trees. That's because the inductance changes
> >> > due
> >> > to the change in geometry and this takes it out of resonance. I think
> >> > this
> >> > effect may be in the order of +/- 10% in moderate wind, so the signal
> >> > strength change is not all that severe.
> >> >
> >> > Bill
> >> >
> >> >> From: theumpire at verizon.net
> >> >> To: lowfer at mailman.qth.net
> >> >> Date: Fri, 29 Jan 2010 02:41:58 +0000
> >> >> Subject: Re: [Lowfer] WM and MP post dinner shot
> >> >>
> >> >> Great job Bill! Thats a fine signal down here in the Poconos!
> >> >> I just put my new transmitter on last night.I put a 7414 buffer stage
> >> >> in
> >> >> it. I was having some drifting problems under long keydowns. I also
> >> >> used
> >> >> a
> >> >> series regulator in the supply but I still want to replace the supply
> >> >> someday.
> >> >> I used one of the Digi-Key transformers you suggested . I found that
> >> >> I
> >> >> had
> >> >> to use 20 turns on the primary to get the final down to 1 watt input
> >> >> at
> >> >> resonance.
> >> >> Right now its very windy here . Im monitoring my signal using
> >> >> Spectrumlab
> >> >> and a downconverter. I see no frequency pulling here BUT I still
> >> >> notice
> >> >> that the final current bounces around a bit on heavy wind gusts. Do
> >> >> you
> >> >> have
> >> >> issues with your loops also in the wind or do I still have a problem
> >> >> with
> >> >> mine?
> >> >>
> >> >> 73
> >> >> Rick
> >> >>
> >> >>
> >> >>
> >> >>
> >> >> ----- Original Message -----
> >> >> From: "Bill Ashlock" <ashlockw at hotmail.com>
> >> >> To: <lowfer at mailman.qth.net>
> >> >> Sent: Thursday, January 28, 2010 4:38 AM
> >> >> Subject: Re: [Lowfer] WM and MP post dinner shot
> >> >>
> >> >>
> >> >> >
> >> >> > Hi Rick,
> >> >> >
> >> >> > Thank you for shutting down PBO to do some watering hole searching.
> >> >> > For
> >> >> > the record, the upper, and typically stronger, of the two Wms is
> >> >> > from
> >> >> > Andover, MA, and the lower is from Ellsworth, NH in the White
> >> >> > Mountains
> >> >> > about 100 miles to the north. As I have said before, both stations
> >> >> > have
> >> >> > identical transmitters and identical loops pointed E/W. The ground
> >> >> > conductivity, however in Ellsworth is much poorer than Andover's
> >> >> >
> >> >> > The next experiment will be to output more radiation from Ellsworth
> >> >> > in
> >> >> > an
> >> >> > attempt to equalize the signals at most receiving sites by replacing
> >> >> > the
> >> >> > #12 loop wire with RG-8 of an identical length. According to my
> >> >> > calculations the lower loss resistance (Rac) of RG-8 should add
> >> >> > approx
> >> >> > 3.6db to the signal after readjusting the turns ratio in the loop
> >> >> > matching
> >> >> > transformer so that the input power remains at 1w.
> >> >> >
> >> >> > Hope you can continue to monitor the watering hole in the future.
> >> >> > I'll
> >> >> > also check out your signal from time to time.
> >> >> >
> >> >> > 73
> >> >> >
> >> >> > Bill
> >> >> >
> >> >> >> From: theumpire at verizon.net
> >> >> >> To: lowfer at mailman.qth.net
> >> >> >> Date: Thu, 28 Jan 2010 01:50:33 +0000
> >> >> >> Subject: [Lowfer] WM and MP post dinner shot
> >> >> >>
> >> >> >> WM and MP gettin stronger! Think conditions are going to be good
> >> >> >> tonight.
> >> >> >> Hope I get "PBO" soon !
> >> >> >>
> >> >> >> http://www.ka2pbo.com/captures/WM%20and%20MP%201-28-10.jpg
> >> >> >>
> >> >> >>
> >> >> >> Rick "PBO"
> >> >> >
> >> >> > ______________________________________________________________
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> >> >> 07:36:00
> >> >
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