I believe that whenever possible, the use of JT65 should be discouraged in
favor of JT9 on HF and *especially* 160.
JT65 is an EME mode and below 15 meters, it is INFERIOR to JT9 as Jim
pointed out.
Last time I listened on HF (forget where, some band between 15m to 80m)
that portion of the band was completely full of JT-65 signals. JT9 is slow
to catch on.
Here's what JT himself says at
http://physics.princeton.edu/pulsar/k1jt/wsjtx.html :
" ... JT65 was designed for EME (“moonbounce”) on the VHF/UHF bands ... in
contrast, JT9 is optimized for HF and lower frequencies.
JT9 is about 2 dB more sensitive than JT65A while using less than 10% of
the bandwidth.
... A 2 kHz slice of spectrum is essentially full when occupied by ten
JT65 signals. As many as 100 JT9 signals can fit into the same space,
without overlap. ..."
I certainly look forward to a little JT9 and WSPR on 160m later on.
I'm glad this thread got started, because I believed that at least 100W was
needed for JT9 or WSPR for that kind of distance on 160 in order to get
through the lightning QRN. Apparently not.
73, Mike
www.w0btu.com
On Thu, Sep 10, 2015 at 3:29 PM, Jim Brown <jim@audiosystemsgroup.com>
wrote:
>
> Remember that WSPR and K1JT's JT65 and JT9 have a LOT of noise immunity.
> JT65 can decode down to at least -24dB, JT9 to -26dB, WSPR to -29dB. The dB
> reference is, I think, the noise in the RX bandwidth, which is usually
> about 2.5 kHz. The occupied bandwidth is about 200 Hz for JT65, 20 Hz for
> JT9, and 6 Hz for WSPR.
> ...
> If you want to try some JT65 or JT9, download and install the latest
> version of WSJT-X,
>
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|