Hi Leigh.
The callsigns are source encoded into 28 bits, the grid in 15 bits.
This gives 71 bits total for 2 callsigns and a grid.
If the same information is exchanged by 6 bit letters of Contestia, 94
bits will be nescessary. That gives coding gain of
10*log(94/71)=1.21dB supposing the same baud
All:
I used Pathsim to compare the sensitivity of JT65A
vs MFSK, PSK31 and OLIVIA using AWGN to alter the
SNR. I ran direct-path with no ionospheric
disturbance.
The chat modes decoded with error-free print down
to -12 to -14db SNR. The JT65A mode decoded
at -27db SNR (signal inaudible).
Hello to all,
Comparizon with S/N Multipsk figures.
According to JT65 specifications, this mode decodes with few errors down to -23
dB, with a normalized band of 2.5 KHz.
All Multipsk figures are normalized with a band of 3 KHz. -23 dB in 2.5 KHz is
about -24 dB in 3 KHz band (-23.792 dB
Hi Patrick,
Are you thinking about incorporate J65A in Multipsk? It would be great
LA5VNA Steinar
Patrick Lindecker wrote:
Hello to all,
_Comparizon with S/N Multipsk figures._
According to JT65 specifications, this mode decodes with few errors
down to -23 dB, with a normalized
On Fri, 20 Apr 2007 23:20:49 -0400
Andrew O'Brien [EMAIL PROTECTED] wrote:
I like Shetland John's idea about deep search work on 12 or 10 M. I
think I will give it a try tomorrow on 12 and see what I come up
with. Will check prop charts for best time to north of John O'
Groats...
Andy
Hello Steinar,
The problem in JT65 is that the important part of the Reed Solomon
coding/decoding (RS tables...) is not described. Moreover, it is writen in the
JT65 specifications (about RS decoding):
it is based on a research paper by Ralf Koetter and Alexander Vardy and uses
computer code
I am not sure if the UTC time is correct since the announcement says
8 AM it might be 1200 UTC, not 1300..
Andy
-- Forwarded message --
From: [EMAIL PROTECTED] [EMAIL PROTECTED]
Date: 21 Apr 2007 10:57:41 -
Subject: [wsjtgroup] Random QSO Hour 13:00 - 15:00 UTC Meteor
I'm perplexed by the edited dB figures.
On JT65A HF it doesn't make any sense that the values are -5 or -6 db
when the signal is strong and moving the S-meter to s5 or s6.
Here we use a 300Hz filter and the audio output is adjusted to read
about 0db with no signal. What I would have expected is
On Sat, 21 Apr 2007 10:32:25 +0100
John GM4SLV [EMAIL PROTECTED] wrote:
I'm going to try CQ on 24.910 (DF 0hz) on Fist Minute for most of the
day while I'm around the house. I don't expect to be overwhelmed with
a pile up!
My simple station at the moment is IC706mk2g, set to ~20w on the
I'm not sure which Shetland island you are on John, I checked the Lerwick
market web cam but did not see you out doing your shopping. I will try you
later.
Andy K3UK
On 4/21/07, John GM4SLV [EMAIL PROTECTED] wrote:
On Sat, 21 Apr 2007 10:32:25 +0100
John GM4SLV [EMAIL
On Sat, 21 Apr 2007 09:37:31 -0400
Andrew O'Brien [EMAIL PROTECTED] wrote:
I'm not sure which Shetland island you are on John, I checked the
Lerwick market web cam but did not see you out doing your shopping.
I will try you later.
Andy K3UK
Hi Andy,
Just returned and see absolutely no
John, name is Andy and am in FN02hk . I have been monitoring 12M while
watching footy on the telly but just checked and see no received signals
from anyone on 12M. I will transmit for a while and see if anyone picks me
up.
Andy.
On 4/21/07, John GM4SLV [EMAIL PROTECTED] wrote:
On Sat,
On Sat, 21 Apr 2007 12:58:12 -0400
Andrew O'Brien [EMAIL PROTECTED] wrote:
John, name is Andy and am in FN02hk . I have been monitoring 12M
while watching footy on the telly but just checked and see no
received signals from anyone on 12M. I will transmit for a while and
see if anyone picks
Hello brian,
The S/N referenced to a bandwidth is used to compare modes under a noise
environment criteria.
A minimum S/N of 0 dB means that with an equal power (let's say 1 watt) of
signal and noise (noise distributed over a 3 KHz band so with a density of
0.33 W/KHz), the signal transmitted
Hi John
I have be monitoring 24.910 almost the hole day with no luck, but
I was able to work South Africa on 40meter (7.045 USB) with
my 12 m dipole right now.
The antenna is about 8 meter above the ground and I was using 75W.
193700 3 -21 0.1 -8 3 * LA5VNA ZS6WAB KG461 10
Thank you Patrick for the explanation. No doubt the mode has solid
theoretical resons for what it edits. Intercomparing various digital
modes has some merit-- like for a Ph.D thesis or marketing.
However as a user, the present value edited isn't a number that is too
useful.
It apparently
Now that images are legal to transmit (in the USA) and MFSK16 is set
for this in MixW and Multipsk, I wonder if it has been determined
useful ? I rarely hear/see any use of this function. .
--
Andy K3UK
Skype Me : callto://andyobrien73
www.obriensweb.com
Andrew O'Brien wrote:
Now that images are legal to transmit (in the USA) and MFSK16 is set
for this in MixW and Multipsk, I wonder if it has been determined
useful ? I rarely hear/see any use of this function. .
-- Andy K3UK Skype Me : callto://andyobrien73 callto://andyobrien73
I'm used to AFSK RTTY and keeping the ALC to a minimum. What about
FSK RTTY I notice my current settings produce a moderate amount of ALC
readings.
--
Andy K3UK
Skype Me : callto://andyobrien73
www.obriensweb.com
Andy,
I think it does not matter. RTTY has no envelope and nonlimear
amplifiers (Class C, etc) can be used with it.
Watch the ALC only for modes with an envelope, ie PSKxx.
73,
Jose, CO2JA
Andrew O'Brien wrote:
I'm used to AFSK RTTY and keeping the ALC to a minimum. What about
FSK RTTY I
-Thanks Roger and Leigh,
How much SNR is needed to get a good picture on a typical HF band?
Andy
-- In digitalradio@yahoogroups.com, Roger J. Buffington
[EMAIL PROTECTED] wrote:
Andrew O'Brien wrote:
Now that images are legal to transmit (in the USA) and MFSK16 is set
for this in MixW
I was at work all day, but monitored 24910 from about 1400Z to Z .
some consistent activity
on a couple of different DF's, but nothing decoded into a callsign
Can do the same tomorrow
John
VE5MU
Hello Cesco...
I am assuming the file is created automagically by the software.
What's the purpose of the date? Should I go in and edit the file
manually?
Howard W6IDS
Richmond, IN
- Original Message -
From: cesco12342000 [EMAIL PROTECTED]
To: digitalradio@yahoogroups.com
Sent:
First a bit of brag.
This afternoon on 20m
041300 1 -8 -0.1 -13 3 * CQ ZS6WAB KG461 10
041500 7 -6 -0.1 -11 3 # VK5OA ZS6WAB KG46 OOO 1 10
041700 10 -9 -11 4 RRR ?
041900 3 -8 -0.2 -11 3 * -16DB TU 30M
In Andy's excellent Bozo's Guide the suggested operating frequency on 40
for JT65 is 7076.
Here in this part of the world 7050 - 7100 is the main SSB operating
area and 7075 is a very popular mobile SSB operating frequency.
So we would, by Gentleman's agreement not operate JT65 on 7076
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