Re: LF: Re: HF SWR meters on MF?

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

Just  going  through  a  phase then ?

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From: "Alan Melia" <alan.melia@btinternet.com>
Sent: Sunday, September 29, 2013 9:38 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: Re: HF SWR meters on MF?

> No he is just emphasising his status as a boring ol' G3 pedant :-))
> alan
>
> ----- Original Message ----- 
> From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Sunday, September 29, 2013 7:57 PM
> Subject: Re: LF: Re: HF SWR meters on MF?
>
>
> > Ha  Alan is  making a technical  point  ... : 0,)
> >
> > --------------------------------------------------
> > From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
> > Sent: Sunday, September 29, 2013 7:26 PM
> > To: <rsgb_lf_group@blacksheep.org>
> > Subject: Re: LF: Re: HF SWR meters on MF?
> >
> > > Does it not?
> > > I suggest to do a test:   Use a MF antenna (on 160m, for this test), 
> > > resonate it to the TX frequency by using a variometer. Then use a 
> > > ferrite transformer to match the impedance to 50 Ohm.
> > > Insert the SWR meter (i'm using this one for HF: 
> > > http://www.astrosurf.com/luxorion/Radio/swr-meter.jpg   (you can find 
> > > the words "SWR" and "meter" on the instrument) into the signal path.
> > > I bet it will show something close to 1:1. The detune the variometer 
> > > (i.e. add a significant reactive component to the feed point impedance) 
> > > so that the resonance is lost. I bet that the reflected power will rise 
> > > dramatically. Then i interprete that the SWR meter tells me that i have 
> > > lost the resonance, since the ratio of the transformer didn't change. 
> > > Sure, there could be a change of the earth losses which cause a change 
> > > of the resistive component of the impedance. This will result in a 
> > > change of the SWR as well. But these changes are small compared to the 
> > > possible change of the reactive part, especially on MF and LF...
> > > 73, Stefan
> > >
> > >
> > > Am 29.09.2013 20:02, schrieb Alan Melia:
> > > > er ......an SWR "meter" will tell you nothing about resonance :-))
> > > > Alan
> > > > G3NYK
> > > >
> > > > ----- Original Message ----- From: "Stefan Schäfer" 
> > > > <Stefan.Schaefer@iup.uni-heidelberg.de>
> > > > To: <rsgb_lf_group@blacksheep.org>
> > > > Sent: Sunday, September 29, 2013 6:34 PM
> > > > Subject: LF: HF SWR meters on MF?
> > > >
> > > >
> > > > > Hi MF,
> > > > >
> > > > > Did someone try to use a normal HF SWR meter on 630m? They are 
> > > > > specificated down to 1800 kHz of course but what about 472 kHz?
> > > > > At least it would be good to get some indication that:
> > > > >
> > > > > -There is some output power (e.g. when using an IC706)
> > > > > -One is coming closer to resonance
> > > > > -Impedance is/comes close to 50 Ohm
> > > > >
> > > > > I'm supporting a new potential MF RX station with limited equipment 
> > > > > (no oscilloscope...)...
> > > > >
> > > > > 73, Stefan/DK7FC