LF: Re: re: Further MF impressions

["mal hamilton" <g3kevmal@talktalk.net>]

Laurence

I am on the East coast near the sea and both 160/600 are similar. I suppose at other locations things might be different although when I have been elswhere I have never noticed that the top end of the MF BROADCAST BAND differs much from the lower end in other words, seems fairly linear from 520 Khz to 1700 Khz. For a given distance the signals are just as strong at one end as the other during daytime and during darkness when the band opens up for DX

Mal/G3KEV

 

 

----- Original Message -----

From: Laurence KL7UK

To: rsgb_lf_group@blacksheep.org

Sent: Sunday, June 17, 2012 3:48 PM

Subject: LF: re: Further MF impressions

Ive found 160/600m dx and even ground wave coverage very different dependent on Geographic and Geomagnetic latitudes, topography etc. Even the Iono QRN affects from lightning has a different "taste"

It may be the same with Mal in the UK but my personal view is it hasnt played out that way in a number of places Ive operated in/on globally. Vivre la/le difference! (apologies!)

Laurence KL1X enroute to AK (yipee)

> From: g3kevmal@talktalk.net
> To: rsgb_lf_group@blacksheep.org
> CC: rsgb_lf_group@blacksheep.org
> Date: Sun, 17 Jun 2012 15:26:39 +0000
> Subject: LF: Re: Re: Further MF impressions
>
> Alan
> I work both 160 metres and 600 metres and find both similar. Daytime range
> and night time similar.
> but you must compare like with like power and antenna wise.
> I use a 1/4 wave inv L on each band up at 100 ft vertical, but naturally the
> 600 metre antenna is less efficient than the 160 metre therefore one has to
> adjust the power on 160 to get the same erp for comparison purposes. In my
> case 10w erp on each band
> For those fiddling about with 400w pep on 160 and a variety of antennas and
> unknown erp and those with a few watts on 600 metres and often very small
> antennas you cannot draw any rational comparison
> I can work over the same distances daytime on 160 or 600 and after dark the
> same applies to dx locations.
>
> de mal/g3kev
>
>
> ----- Original Message -----
> From: "Alan Melia" <alan.melia@btinternet.com>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Sunday, June 17, 2012 2:54 PM
> Subject: LF: Re: Further MF impressions
>
>
> > Stefan, the groundwave does not change, but what you have is varying
> amounts
> > of skywave and daytime "fading" The wavelength is only a quarter of that
> at
> > 136kHz so it only tales a quarter of the change in (apparent) reflection
> > height to give the same sort of constrctive and destructive interference.
> > 500kHz does not travel over land so well as the surface "roughness" is
> > bigger wrt a wavelength ( but even rough seas are generally less "rough"
> > than land ) Yes 500k is an interesting frequency and quite different to
> both
> > 136 and top-band. There are times of the day when the fading can be
> vicious
> > at relatively short range Also with the shorter wavelength most antenna
> > height limited stations can have up to 16 times more ERP than at 136kHz
> >
> > Enjoy the new "playground" :-))
> >
> > Alan G3NYK
> >
> > ----- Original Message -----
> > From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
> > To: <rsgb_lf_group@blacksheep.org>
> > Sent: Sunday, June 17, 2012 3:03 PM
> > Subject: LF: Further MF impressions
> >
> >
> > > MF,
> > >
> > > I just thought my receiver isn't working correctly. I thought the xtal
> > > does not start to oscillate due to the higher ambient temperatures in
> the
> > > afternoon. But later i found that the band noise on MF is significantly
> > > lower than in the evening, at least 20 dB. So now i see that the band
> > > noise is about 5 dB above my soundcard noise with the current setup.
> > >
> > > What do others know about the ground wave range in summer and in the
> > > afternoon? When does the band open? Similar to LF?
> > >
> > > BTW thanks to DF6NM for the grabber. Nice tool to get some experience in
> > > these first days...
> > >
> > > 73, Stefan/DK7FC
> > >
> >
> >
>
>