Topband: Inquiring minds want to know....

[Larry]

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