Re: Topband: Bottom End Beacons

[Adrian Fabry]

Yesterday evening they were S9 on my poor 6m high INV-L. The 1810-1820
interval is unusable here.

73 Ady YO2NAA

On Tue, Feb 20, 2018 at 11:09 PM, Jean-Paul Albert via Topband <
topband@contesting.com> wrote:

> Yes Mark , around 6 pm GMT time louder than the days before.
> Shorter propagation by the moment I suppose because no eastern station at
> the grey line today.
>
> 73´
> Jean Paul
>
>
> Envoyé de mon iPad
>
> > Le 20 févr. 2018 à 21:29, Mark van Wijk  a écrit :
> >
> > And just tonight they are loud again: https://www.flickr.com/photos/
> pa5mw/39676032834/in/dateposted/
> >
> > Signal level:  25dB above bandnoise
> >
> > RX antenna: 60mtr  BOG in a ditch QTF 30
> >
> >
> > 73
> > Mark, PA5MW
> >
> >
> >> On 2/20/2018 10:41 AM, Roger Kennedy wrote:
> >> Yes, upon searching, I came across Alan Cordwell's web pages that he
> wrote
> >> about the old Decca HiFix navigation beacons that used to be VERY strong
> >> here in Britain, but closed down during the 90s.
> >>
> >> I emailed him about these, as they sound very similar.
> >>
> >> He confirmed that they are a Russian system that works in much the same
> way,
> >> and have low power transmitter around the Baltic.
> >>
> >> As Mark posted, here's a link to Alan's webpage which shows you how they
> >> sound:
> >>
> >> http://alancordwell.co.uk/Legacy/radionavigation/russian/bras.html
> >>
> >> They are used by fishermen to pinpoint their position so they can locate
> >> fish stocks - that's why I referred to them as fishing beacons.
> >>
> >> I'm amazed some of you can hear them in the US, as they're rarely very
> >> strong here - typically between S2 and S9, but generally around S5.
> >>
> >> But the thing to remember is that there are about 15 of them spaced
> evenly
> >> between 1800 and 1820 kHz . . and they are quite wide.  So these will
> often
> >> block out weak DX signals here in Europe.  So worth avoiding that part
> of
> >> the band.
> >>
> >> Hopefully they will turn them off soon, and just use GPS !
> >>
> >> 73 Roger G3YRO
> >>
> >> _
> >> Topband Reflector Archives - http://www.contesting.com/_topband
> >
> > _
> > Topband Reflector Archives - http://www.contesting.com/_topband
>
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
>



-- 
73 Ady
YO2NAA
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Inverted-L with coil on the top of the vertical section

[Adrian Fabry]

Hi James,

Thank you for the hint. I read the article, and I see t's a very good
solution. For the moment I can't install this elevated FCP.

I have to mention my soil is good, quite wet most of the winter.

73 Ady YO2NAA

-Original Message-
From: James Bennett [mailto:w6...@me.com] 
Sent: Wednesday, February 11, 2015 2:30 AM
To: Adrian Fabry
Cc: topband@contesting.com
Subject: Re: Topband: Inverted-L with coil on the top of the vertical
section

Ady - you might consider using a Folded CounterPoise, designed by K2AV, for
your radial system. I have one on each of my Inverted L antennas; 160  80
meters. They work quite well if you do not have the real estate for a lot of
radial wires. My 160 Inverted L only goes up 35-40 feet bit with the FCP it
performs very well. 




 On Feb 10, 2015, at 2:09 PM, Adrian Fabry yo2...@gmail.com wrote:
 
 Hello all,
 
 
 
 I'd like to build an Inverted-L antenna. Unfortunately the vertical
section
 will be only 8m (26 ft) high and the radial system not great (maybe 5 to
10
 wires laying on the ground)
 
 The simulation (with MMANA software) indicate 3.5 +j0 Ohm impedance. This
is
 very low so I think most of the power will be lost in the ground. 
 
 In order to raise the impedance, I would insert a coil (about 75 uH) on
the
 top of the vertical section and restore the resonance with 48.7 pF series
 capacitor on the feed point. 
 
 This will raise the impedance to 34 ohm. 
 
 
 
 Is this solution OK? Should I better place the coil at the feed point ?
 
 
 
 I know it would be much better to increase the height of the vertical
 section and to install more radials or a ground screen, but this is not
 possible for the moment, so I have to find the best compromise.
 
 
 
 
 
 Thanks for reading.
 
 
 
 73 Ady YO2NAA
 
 _
 Topband Reflector Archives - http://www.contesting.com/_topband

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Topband: Inverted-L with coil on the top of the vertical section

[Adrian Fabry]

Hello all,

 

I'd like to build an Inverted-L antenna. Unfortunately the vertical section
will be only 8m (26 ft) high and the radial system not great (maybe 5 to 10
wires laying on the ground)

The simulation (with MMANA software) indicate 3.5 +j0 Ohm impedance. This is
very low so I think most of the power will be lost in the ground. 

In order to raise the impedance, I would insert a coil (about 75 uH) on the
top of the vertical section and restore the resonance with 48.7 pF series
capacitor on the feed point. 

This will raise the impedance to 34 ohm. 

 

Is this solution OK? Should I better place the coil at the feed point ?

 

I know it would be much better to increase the height of the vertical
section and to install more radials or a ground screen, but this is not
possible for the moment, so I have to find the best compromise.

 

 

Thanks for reading.

 

73 Ady YO2NAA

_
Topband Reflector Archives - http://www.contesting.com/_topband