I think that "fad " might be a tad strong. Personally I am amazed at J65 and
it's ability to work under very low signal conditions.
The other night I worked JA on 20M without ANY indication of a signal, just one
tiny spike, and nothing by ear.
I would however happily switch to another mode which could function almost as
well, but one that would permit
ragchewing keyboard to keyboard under very low signal conditions.
The other thing that J65 did, is drove home the fact that a band might appear
dead, but is not......... propagation is a strange and wonderful thing!!!
John
VE5MU
----- Original Message -----
From: Andrew O'Brien
To: digitalradio@yahoogroups.com
Sent: Friday, April 20, 2007 8:25 PM
Subject: Re: [digitalradio] Re: Straight talk on JT65a
Good work Leigh, I was wondering about some of those -31 readings that I
could hear with my ears. I think Olivia testing is a good thing for this
weekend.
Bonnie, the "fad" is an interesting issue. Certainly weak signal performance
is a popular goal, but I wonder if it JT65A is popular in part to the format.
If we used Olivia in short bursts with very structured exchanges, and the
Olivia software popped up SNR reports (like MixW does for Olivia, or PC-ALE
does for ALE) , I wonder if Olivia would outperform and be more popular than
JT65A? I'll argue that its not just the performance of JT65A but the
format.
Andy
On 4/20/07, expeditionradio <[EMAIL PROTECTED]> wrote:
--- In digitalradio@yahoogroups.com, "Leigh L Klotz, Jr." <[EMAIL
PROTECTED]>
wrote:
> My conclusion is that this mode is about 10-15 dB worse than
> it appears to be, and we should start doing more careful
> tests alongside Olivia and plain old MFSK as controls in
> side-by-side propagation conditions.
> 73,
> Leigh/WA5ZNU
>
Hi Leigh,
After a week or so of monitoring JT65A on 14MHz and 7MHz, I tend to
support your conclusions.
It appears that "not-pre-defined-QSO" texting on JT65A is similar to
Olivia 250/8 for weak signal robustness on HF. Although the throughput
of texting via Olivia 250/8 is rather slow, it far exceeds glacially
slow JT65A.
Nonetheless, the recent fad flurry of activity on 14076 with JT65A
demonstrates the enthusiasm for any potential new extreme weak signal
modes during the bottom of the solar cycle.
Bonnie KQ6XA
--
Andy K3UK
Skype Me : callto://andyobrien73
www.obriensweb.com
------------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.446 / Virus Database: 269.5.5/769 - Release Date: 4/19/2007 5:56
PM
