the
> article,
> the test was CW at 12 wpm and 9 Hz filter BW , no ring using WWV as time
> source for the synchronization.
>
> That was state of the art back in the early 70's, almost 50 years ago.
>
> 73's
> JC
> N4IS
>
>
> -Original Message-
> From: Topband [
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of K4SAV
Sent: Monday, December 24, 2018 3:10 PM
To: topband@contesting.com
Subject: Re: Topband: FT8 - How it really works
Although I have finished my FT8 testing, there is one final thought I would
like to leave
t from Mail for Windows 10
>
> From: K4SAV
> Sent: Monday, December 24, 2018 2:10 PM
> To: topband@contesting.com
> Subject: Re: Topband: FT8 - How it really works
>
> Although I have finished my FT8 testing, there is one final thought I
> would like to leave with you, a
stations!
>
>Just sayin’.
>
>Chuck W5PR
>
>Sent from Mail for Windows 10
>
>From: K4SAV
>Sent: Monday, December 24, 2018 2:10 PM
>To: topband@contesting.com
>Subject: Re: Topband: FT8 - How it really works
>
>Although I have finished my FT8 testing, th
sayin’.
Chuck W5PR
Sent from Mail for Windows 10
From: K4SAV
Sent: Monday, December 24, 2018 2:10 PM
To: topband@contesting.com
Subject: Re: Topband: FT8 - How it really works
Although I have finished my FT8 testing, there is one final thought I
would like to leave with you, and also to correct
Although I have finished my FT8 testing, there is one final thought I
would like to leave with you, and also to correct one statement I made
earlier. Someone thought FT8 measured the noise in the interval when
the FT8 signals were off, and I replied that would result in a real S/N
number.
Jerry,
If you would like to do some mid-day comparison testing between FT8 and CW,
let me know. Looks like the path length is about 400 miles.
Jim,
K9SE
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Still doing FT8 testing this morning 3 hours after sunrise I looked for
something resembling dead band conditions with only a few weak stations.
There was nothing on 160 but the west coast guys were still on 80. They
were weak but there. They would have been good copy on CW but FT8 was
Yesterday I said " I don't have a measurement with the results of that
showdown of CW versus FT8 in dead band conditions but the answer would
be interesting to know."
This afternoon I tried to get an answer to that. I wanted to see if FT8
would decode a station I couldn't hear. I wanted
Jerry:
Clever way to evaluate FT8 SNR reports with your VFO 1 and 2 comparisons.
I often see positive numbers on FT8 160 meter signal reports for strong
stations on FT8. For example -- if a station is S9 + 10 dB audible, then it
reads a positive number
for the FT8 signal report.
At the risk
Correct me if im wrong:
A K3 owner could easily check this.
You need 2 computers, running WSJT on both. Don't know if you can run 2
instances of WSJT on a single computer. Feed the left channel from LINE
OUT (=mainRX) to one instance of FT-8 and the right channel (=sub-RX) to
the other
Hi,Narroving filter in WSJT-X digi modes will degrade decodes! Best performance
you'll get using wide open filters on you radio.I sugest you to look at the
WSJT-X archives and find the answer to your question by the author it self -
K1JT.As we are radio Amateurs i beleive its worth to
On 2018-12-20 11:45 AM, K4SAV wrote:
> In the case of a crowded band it becomes obvious that CW is much
> superior to decoding a weak signal because all those strong signals
> limit the ability of FT8 to decode a weak signal.
That is only true if you leave AGC enabled and the strong signals
Thanks to the folks commenting on how FT8 works.
VE3KI said:
"The noise floor the wsjt-x signal is referenced to is the noise within
the bandpass during the two-second period when no-one is transmitting,
not the signal level when people are transmitting."
That was what I originally thought
HI,
Thanks for sharing experience!
Question to FT8 and "noise" relations - In usual case everything in
passband is noise except signal of interest.
So with only one FT8 signal and white noise in passband S/N can be
increased narrowing passband till it matches signal width. EME guys know
that
That would be my definition of noise power also. That would not help
explain the numbers produced by FT8.
It's curious that my VFO1 - VFO2 measurement produces numbers very close
to what FT8 reports. I have no information as to why that should be,
only measurements that produce those
Is the definition of "noise floor" being changed for FT8?
WSJT-X (and WSJT before that) defines noise as the integrated value
of noise (noise power) across the 2500 Hz (approximately based on
the receiver filter) receive bandwidth.
73,
... Joe, W4TV
On 2018-12-19 9:57 PM, K4SAV wrote:
Joe, thanks for the information. I am not exactly sure what all that
means. My conclusions were based on observed data. It seems pretty
obvious to me that a signal that is more than 50 dB above the noise
floor should not receive a S/N number of -1 dB, which is what FT8
gives. I don't know
On 2018-12-19 4:28 PM, K4SAV wrote:
> The official documentation for FT8 says it will decode signals 24 dB
> below the noise floor. That is not a correct statement most of the
> time.
No, that is a correct statement. Signal reports in WSJT-X for FT8, JT65
and JT9 are *all* measured *with
While sitting around being bored and recovering from a gall bladder
operation, I decided to do some experiments with FT8. First thing I did
was upgrade the software to WSJT-X v2.0.
I hope this post doesn't turn into another FT8 bashing session. My only
goal was to understand how this mode
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