Topband: 160m dethroned? 600m the new top band?

donovanf at donovanf at
Mon Feb 13 07:31:00 PST 2012

It isn't hard to produce 5 watts eirp at 472 kHz, a few hundred watts watts through a tuner into your favorite 160 or 80 meter vertical will do the job easily.

Much higher noise levels at 472 khz present a significantly more difficult challenge than 160 meters, and DX propagation is also much more difficult.  

Rural receiving locations are a big plus.  A very quiet remote rural oceanfront receiving location will provide a huge  benefit. There's no need for tunable remote receivers, the entire 6 kHz band could easily be digitized and streamed on the internet.  Perhaps a solar powered remote receiving site miles from homes and power lines, similar to ZL3IX's remote 160 meter oceanfront receiving site.

If the 473 kHz band is allocated, expect to see lots of WSPR activity and other advanced modulations, CW not so much except for relatively short distance QSOs on other than the rare exceptionally good night.

RSGB provides excellent reporting of WRC-12 progress, this is their latest report:

Agenda Item 1.23 – 500kHz

The first reading of the text for an amateur service band at 472-479 kHz was presented to the WRC-12 plenary this evening. This text provides for a global allocation to the amateur service with a maximum radiated power of 1W (EIRP). Administrations however, may permit stations located more than 800km from the borders of countries listed in a footnote a maximum radiated power of 5W (EIRP). While the basic regulatory text remains the same, there was a long discussion on the structure of the two new footnotes listing those administrations who want to upgrade their aeronautical radionavigation service to primary status and those who will not permit any amateur service operation on this band. As a result the text was referred back for revision of the footnotes and will be re-presented for first reading early next week.

Agenda Item 8.2 – Future Agenda Items

5 MHz

The Draft Resolution for the proposal from Cuba – to consider the possible new allocation to the amateur service on a secondary basis at around 5,300 kHz in accordance with Resolution [Amateur-HF] (WRC-12) – was approved by Working Group 6C despite strong opposition from Iran, Japan, Korea, the Russian Federation and the United Arab Emirates. Countries supporting this Cuban proposal included Argentina, Brazil, Canada, New Zealand, Uruguay and Venezuela. Both the Russian Federation and the UAE suggested that if this should become an agenda item then it should be considered for the 2018 conference. The proposal will now be considered by Committee 6 in coming days.


---- Original message ----
>Date: Mon, 13 Feb 2012 09:48:49 -0500
>From: Rik van Riel <riel at>  
>Subject: Topband: 160m dethroned?  600m the new top band?  
>To: topband at
>Things are looking good at WRC-12. Approval of an international
>amateur radio allocation around 470 kHz seems very likely:
>This does, of course, lead to the question of antennas.
>What can people without a few acres to dedicate to 600m do to
>get a vaguely decent antenna?
>I started modeling an inverted L with an FCP and a loading
>coil the size of a rain barrel.  Then I added more top wires,
>in more directions, and the loading coil is only half the size
>of a rain barrel :)
>Before loading coil losses, gain is about -10dBi!
>Nowhere near as easy as 160m, but this could be a very
>interesting antenna challenge for hams...
>All rights reversed.
>UR RST IS ... ... ..9 QSB QSB - hw? BK

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