> From: [email protected]
> To: [email protected]
> Date: Thu, 24 Oct 2013 17:09:43 +0100
> Subject: LF: 74kHz - history
>
> Bob, here is a potted history of the UK 73kHz band:
>
> The long term plan was always for a long-term international
> allocation. This was going to take some time and so an interim
> allocation was negotiated by the RSGB at 73kHz. This was shared with
> some VERY loud commercial stations. Special permission had to be
> requested to transmit, and the few of us who operated portable had to
> specify when and where we would do it. As with your work, amateurs in
> various countries participated by giving reception reports.
>
> Later, the plan for an international allocation bore fruit, partly
> because of our work on 73kHz demonstrating that amateurs would be
> very unlikely to cause problems to commercial LF users, and we (and
> others) got the 136kHz band. Most activity shifted to that new (and,
> as you have found out, much easier) band, though several of us
> continued with experiments on 73kHz from time to time. The 73kHz band
> was eventually removed from UK amateurs following a change in the
> commercial use of this part of the spectrum.
>
> It is to be hoped that the work of you special licensees on 74, 136
> and 472kHz will eventually lead to some full LF/MF allocations in the
> US.
>
> de Mike, G3XDV
>
> > Mike;
> > Interesting indeed. When you operated here was there a push by the UK
> > ops to move to 137? How did that come about? RSGB influence to move
> > to 137 and just give back 73?
> >
> > > From: [email protected]
> > > To: [email protected]
> > > Date: Thu, 24 Oct 2013 16:11:00 +0100
> > > Subject: RE: LF: 74kHz - WG2XRS/5 callsign at last (2of2)
> > >
> > > Oh yes. But it is a little early in the year and it will reduce as
> > > it does on the other low bands, with some zero static days. When we
> > > had the band some years ago, we were mostly using CW and QRSS3 over
> > > shorter distances (my record was about 1100km) but we tended to
> > > operate early in the morning when the static was at its lowest.
> > >
> > > I reduce the interference here by using the quite effective noise
> > > blankers in my Afedri SDR receiver, together with lots of fast AGC.
> > > Then heavy limiting and a further noise blanker in SpecLab. The
> > > resultant 'holes' are small compared with the QRSS60 bit length.
> > >
> > > de Mike
> > >
> > > > Mike;
> > > > Is that "pesky static" a characteristic of this band-from your
> > > > passed experience?
> > > >
> > > > > From: [email protected]
> > > > > To: [email protected]
> > > > > Date: Thu, 24 Oct 2013 15:30:14 +0100
> > > > > Subject: Re: LF: 74kHz - WG2XRS/5 callsign at last (2of2)
> > > > >
> > > > > Well, Dex that was the good news. The bad news is that, as I
> > > > > cautioned earlier, the lower noise level lower in the band was a
> > > > > function of my antenna pass band, and not of absolute noise. I
> > > > > re- tuned to a lower frequency and it wasn't any better. So the
> > > > > current frequency seems as good as any.
> > > > >
> > > > > Interestingly, I left my SDR plotting a few kilohertz around 74k
> > > > > last night with long integration and I could see the shape of my
> > > > > antenna passband produced by the night-time static acting as a
> > > > > broadband noise generator. At last, I have found a use for that
> > > > > pesky static!
> > > > >
> > > > > de Mike
> > > > > =======
> > > > >
> > > > >
> > > > > > Mike Dennison wrote:
> > > > > > > More pics including the XRS/5 caps.
> > > > > > Thanks Mike! That's a keeper.
> > > > > >
> > > > > > Dex
> > > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> > >
> >
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