[Lowfer] WM and MP post dinner shot
rick kirby
theumpire at verizon.net
Fri Jan 29 22:23:03 EST 2010
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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