HFU HF Underground
General Category => General Radio Discussion => Topic started by: acl12 on January 07, 2012, 1835 UTC
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Hi. My eton g3 often overspills. For example radio Espana at 7275 spans up to 7280. Although at the higher non broadcasts end its only faint it stops me pulling in the correct 7280 frequencies. Is there anything I can do. I bought this radio specifically for dxing. Thanks
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RADIO EXTERIOR DE ESPANA runs some of the highest power transmitters in shortwave today. According to the broadcast info application I downloaded this week Eibi View, REE on 7275 khz is 250,000 watts on a 50 degree azimuth (toward Europe and Russia). It seems no matter which way REE points their antennas their signal comes in strong here in Eastern North America.
http://eibispace.de/
As for the overspill to 7280 khz, that sort of thing can be managed by tuning away from the offending signal or with a radio that has better filters (is more selective). In inexpensive portable shortwave receivers, supposedly the radios based on the Silicon Industries si4734 radio-on-a-chip are quite selective. The G3 doesn't use this chip although I think there are Grundig models which do.
http://swling.com/blog/tag/si4734/
I would be interesting to see an 'SDR waterfall' of Espana on 7275 and an adjacent signal on 7280 to see what kind of overlap is actually there.
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Most SWBC transmissions are 5 kHz wide. So a transmission on 7275 would occupy 7270 to 7280 kHz, resulting in interference with transmissions on 7270 and 7280 kHz. Likewise, a transmitter on 7280 occupies 7275 to 7285 kHz, and would interfere with a transmission on 7275 (and 7285 as well).
Here's a waterfall of REE recorded just now, it sure looks +/-5 kHz wide to me. Tough to tell on the lower side due to another station, but clear on the upper side.
(http://www.hfunderpants.com/mypics/REE7275.jpg)
One solution would be to use ECSS/Sync mode (if your radio has it) and use only the upper sideband from 7280.