Re: LF: MW Antenna [was:RE: Clemens on MF!!]

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

Hi Clemens,

I can see all the solar modules on the neighbours roofs. That may be a 
reason for the QRM (?). I think if you can manage to create an earth 
system in http://no.nonsense.ee/qth/map.html?qth=JN68KJ79XH at the 
current feed point of the antenna and then use a coax cable and an 
isolation transformer or a separate primary winding on the variometer 
coil body then the QRM may be even lower than in the dipole 
configuration :-)
73, Stefan

Am 20.01.2014 21:45, schrieb Clemens Paul:
> Hi Stefan,
>
>    
> > +6 dB, so now you're getting twice the antenna current with
> > the same power?
> >      
> No,only about 10% more (calculated) as the VSWR is a bit better.
> R went from ~60 Ohm to 50 Ohm,reactance being cancelled out.
> The increase in signal strength by 6dB comes from reduced ground losses due
> to vertical polarization as opposed to horizontal polarization in dipole mode.
>
>    
> > Can you show us the image showing your house and the antenna again? I
> >      
> Attached once more for convenience (see also link at the end).
> Red traces = dipole legs (2x155m)
> Yellow trace = open wire feeder (42m)
>
>    
> > remember there was a coax of some 10m between TX and dipole feed point
> >      
> That must be someone different. -:)
> Here the feeder runs directly into the shack,vertical part about 6m.
> So in T-Antenna mode there's quite a bit of top load...
>
> Let's see how I can manage the earth problem.
> I believe for reception I will further stay with the dipole mode because it's 
> extremely
> quiet ( -110dBm or true ~S3 in 200Hz BW) due to careful balancing and its remote
> location from the houses.
> When receiving I can afford up to 10-15dB signal loss on MW without
> degrading SNR.
>
> http://no.nonsense.ee/qthmap/?qth=JN68KJ79WJ
>
> 73
> Clemens
> DL4RAJ