Topband: The use of digital modes on 160 metres

[Jim Brown]

On 9/15/2012 4:29 AM, George, VK5IT wrote:
> I keep a reasonably close eye on the threads posted in the Top Band Archives
> and this is a topic I do not remember seeing being discussed.

It has. Search for JT65.

> so I would be interested in hearing what frequencies and what modes are used on 160 meters and any comments.

There is considerable JT65A activity between about 1838.5 kHz and 1840.5 
kHz, transmitted and received by using K1JT's WSJT9 software or W6CQZ's 
JT65-HF with a transceiver set for 1838 USB.  JT65-HF is the most 
user-friendly of the two programs, and includes multi-decode 
capability.  The bandwidth of a JT65A signal is about 225 Hz, and it is 
common to decode a half dozen different signals during each one-minute 
cycle.  There are times when I see more JT66A signals on Topband than CW 
or SSB!  You can see some of this activity on W6CQZ's Reverse Beacon web 
page.

 From my QTH near San Francisco, I watch stations on the east coast of 
North America working at least one station in VK.  Activity in North 
America slows down a lot during our summer.  It's been quiet here since 
early June, but I expect to see it pick up pretty soon. This spring, I 
heard and decoded both sides of a QSO between W1 and ZS, and called the 
ZS station several times without success.

I don't know of any other digital modes being used on Topband, but that 
doesn't mean that they're not there.

For best decoding, it helps to use a decent (but not expensive) USB 
sound card.  This winter, I bought and tested three low cost units from 
Numark, Tascam, and Byterunner. All three worked fine, and produced 
roughly twice as many decodes as the sound card built into my Thinkpad. 
The Numark and Tascam were well built.  The Byterunner was not. The 
Tascam I bought was a model 100 (about $70), which was recently 
discontinued, replaced by a model 122 (about $80).  The Numark doesn't 
have a model number, but is their lowest cost unit about $35.

73, Jim K9YC