[Lowfer] WM and MP post dinner shot

[Bill Ashlock]

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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