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Re: Topband: Inquiring minds want to know....

To: topband@contesting.com
Subject: Re: Topband: Inquiring minds want to know....
From: Larry <larry@w7iuv.com>
Date: Sat, 8 Feb 2020 14:45:00 -0800
List-post: <mailto:topband@contesting.com>

First thing, 160 meter is NOT the Topband and hasn't been for a number of years. 2200m is the Topband, with 630m in second place, and 160m a distant third.

There are two areas of interest in the MF/LF/VLF world. Amateur and non-amateur/SWL.

If you are primarily interested in just listening and logging many interesting signals, you can spend a lifetime tuning below 500kHz and never hear it all.

Just a few from the high end first approximate frequencies):

Navtex 512kHz

NDB 200-500 kHz

DGPS 300 Khz

LW Broadcast 200kHz +/-

WWVL and similar 60 kHz

Military data 10-35 kHz

Geophysical and atmospheric noises various VLF down to a couple kHz or less

If you are interested in amateur operations including experimental transmissions there are a number of places to look.

630 meter band: lots of amateur activity here. Some CW but mostly JT9 digital. Several hundred station currently active worldwide. Lots of WSPR activity with 630m reports exceeding those from 160m EVERY night! From my rather poor Inland Northwest QTH, I have worked 120 unique calls in 39 states and 7 DXCC so far. The power limit is 5 watts EIRP/ 500 watts transmit power max. With a typical backyard antenna system running about -15 to -20 dBi it might take the whole 500 watts to get 5 watts radiated. Not a band for the timid...

2200m band: lots less activity due to severe physical limitations. 1 watt EIRP/1500 watts transmitter power max. With typical backyard antennas running around -30 dBi, you need a KW to get 1 watt radiated. Probably less than one hundred active transmit capable stations worldwide but many times more than that listening. Most work is WSPR beacons but also JT9 QSO's. I have 11 stations worked in 8 states and 3 DXCC so far.

There is a no license low power band at 187 kHz approximately. I don't know much about this one except there are a number of east coast USA beacons running that I have never been able to hear.

There are several experimental stations that occasionally transmit WSPR beacons on approximately 75 kHz. I have heard a couple of them out to 1000+ miles.

There are a few really motivated experimenters who transmit beacons on about 8 kHz. I've never been able to hear any of them but I believe signals have been copied across the Atlantic in the past.

If you want to know more about the 630 meter band look at :

https://njdtechnologies.net/

John provides a 630 meter daily report of activity plus lots of other info to get you started.


73,

Larry - W7IUV



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