Re: LF: 73kHz

[Roger Lapthorn <rogerlapthorn@gmail.com>]

At the risk of starting a backlash from people here saying, "don't spread the activity even more thinly", is it worth a serious push for 73kHz to be made available again in the UK by NoV?  If the allocation is quiet then surely on a strictly limited access, low ERP, basis and for a limited time there might be some possibility?

For 8.7-9.1kHz we managed to persuade OFCOM to talk with the Met Office, and several of us did so directly to argue our cases, and the outcome was positive and in not too many months. 

I know we have discussed this before.

73 (yes please!) 

Roger G3XBM

On 18 October 2011 18:34, James Moritz <james.moritz@btopenworld.com> wrote:

Dear Stefan, LF Group,

73kHz reception was a problem in the UK because of an FSK utility located at Rugby in the middle of the band, which had strong noise sidebands that created QRM across the whole band. It used to shut down for maintenance for an hour or two each month - then there would be a rush of UK stations trying to work each other in CW. It also lead to the funny situation that the UK-only 73kHz signals could often be received better by stations in mainland Europe, and there were quite a few cross-band 73k - 136k QSOs. Radiating a signal on 73k had the same problems as 136k but more so, and corona, melted insulators etc., tended to be rather common! But quite a few stations managed to transmit reasonable signals.

Once you managed to radiate a signal, it would go a long way, with extended ground wave range compared to 136k, even with rather low ERP. Some QRSS transatlantic signals were received. I think 73kHz was perhaps the first place QRSS was used, with early experiments between G4JNT and G3PLX.  I recall the last 73kHz QSO was between G3XDV and G3LDO, these stations also had the first 2-way QSO on the band. Perversely, the withdrawal of the 73k band happened at about the same time the Rugby FSK utility was decommissioned. Nowadays, this part of the spectrum is remarkably quiet...

Cheers, Jim Moritz
73 de M0BMU

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