Re: Testing VARA.


Andrew OBrien
 

i will try him today

On Wed, Feb 21, 2018 at 10:02 PM, KC9SGV <kc9sgv@...> wrote:
KE7XO is showing on 14.1035 MHz
Nothing heard after three consequous connect attempts from Chicago


On Feb 21, 2018, at 7:58 PM, Andrew O'Brien <andrewobrie@...> wrote:

Is there any activity with VARA on 20M?


On Feb 21, 2018, at 7:27 PM, Andrew OBrien <k3ukandy@...> wrote:

The PIII versus VARA example you posted , while separated by a few minutes and potentially different conditions, does give a ballpark comparison .  I am encouraged.
Andy K3UK

On Wed, Feb 21, 2018 at 6:05 PM, KC9SGV <kc9sgv@...> wrote:


On Wed, Feb 21, 2018 at 5:02 PM, kc9sgv . <kc9sgv@...> wrote:
KC9SGV and others are listening for your VARA call as seen on PSK Reporter.
See Public Gateways (Top Left)
Set target RMS in Connect To.
Run Winlink Express,
Telnet Winlink
Open Session
RMS Relay session
Start




On Wed, Feb 21, 2018 at 4:47 PM, KC9SGV <kc9sgv@...> wrote:
Hi Andy, 
Yes I remember those exciting months testing Winmor.
Here is another way that I am trying to duplicate the European VARA results..
All, feel free to do the same tests.
No Part 97 to complicate things....
Acoustical coupling either via microphones to speakers cross-wise, or direct audio patch cord computer to computer.
Slide the sound card Input and Output Codec sliders way down...!
Isolation transformers in the setup would be cleaner and give higher thruput.
Note : I had to run the gateway server as administrator, to get around the crippling anti-virus software.

<image1.JPG>

KC9SGV


On Feb 21, 2018, at 2:40 PM, Andrew O'Brien <andrewobrie@...> wrote:

Thanks Bernie for sharing this info . I know your call sign from the early days of Winmor and therefor know that you have good experience regarding throughput speeds.

Andy K3UK. 


On Feb 21, 2018, at 12:06 PM, Walter Underwood <wunder@...> wrote:

I am quite familiar with baud and bits. The V.29 modem I worked on 35 years ago was 9600 bits/sec 16-QAM encoding at 1200 baud. V.29 is still used for faxes.


And yes, I know about Shannon, too.

Getting 4000 bps on 10 meters is great, but I would expect that to be a much better channel than most shortwave paths. It should be lower noise without as much “interesting” ionospheric distortion. Since they were reporting best performance, that could have been line of sight on 10 meters.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

On Feb 21, 2018, at 4:39 AM, Rick Muething <rmuething@...> wrote:

    Walter,

Bits per second is related to baud (symbols per second) but one symbol can be 1 or many bits:

e.g.

One carrier,  50 baud, BPSK = 50 bits/sec

One carrier, 50 baud QPSK = 100 bits/sec

One carrier 50 baud 16QAM = 200 bits/sec

40 carriers (OFDM) each 50 baud  16QAM = 8000 bits/sec.

On HF however with our typical low S:N and multipath it is usually difficult to exceed 2 bits/sec/Hz.  The channel capacity (theoretical limit on error-free bits/sec) is related to the channel's  S:N as described in Claude Shannon's brilliant paper of 1948.

Virtually all modern modes work this way sending more than 1 bit per symbol:  VARA, ARDOP, WINMOR, Pactor 3, Pactor 4 etc.

73,

Rick Muething, KN6KB


On 2/20/2018 11:24 PM, Walter Underwood wrote:
Reported in bits per second (as people normally do), that isn’t quite as impressive. About 4000 bps. That is OK, but I implemented a V.29bis modem on a PDP-11 in 1982 and that could do 9600 bps on a clean 4 kHz channel.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

On Feb 20, 2018, at 8:20 PM, KC9SGV <kc9sgv@...> wrote:

Station was attended at all times...

Has busy frequency detect as incorporated already with BPQ.
Will have that also once wrapped inside Winlink Express.

Rumors of 30k+ bytes/min on 10 meters in Europe...

KC9SGV


On Feb 17, 2018, at 8:25 AM, KC9SGV <kc9sgv@...> wrote:

Hi All,

We are testing VARA this weekend on 7.101 MHz USB DIAL.
Impressive legal mode.
Beats P3 on both thruput and robustness.
Milspec digital for the ham bands.
https://rosmodem.wordpress.com

Scroll down


Bernie,
KC9SGV
Chicago







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