Date   

Re: Understanding APSK and QAM Rohde and Schwartz video #VARA

Kristoff Bonne
 

Hi,


I'm a bit puzzled about this.

After watching the video, I I understand that QAM and APSK are two different systems, each with their advantages and disadvantages, and either with the specific usecase.

So I do not understand why combining QAM and APSK is then a good idea. You mix systems, therefor creating something that has the disadvantages of both.



What is the technical argument for these mil-comm systems to use a combination of QAM and APSK constelation?



Kristoff (on1arf)

On 06.08.21 19:01, ALE wrote:

Hi Graham,

QAM is fun, working to develop Military data modem and ALE serial tone modem QAM waveforms.

In my attached photo the QAM waveform in the constellation display is an MS110B offering, going into MS110C/D Appendix D and 4G ALE get even more complicated, I have not made it to 256-QAM yet, the Appendix waveforms and 3G ALE are in my near future however.

The SCS P4 serial tone modem stops at 32-QAM in less than a 3kHz channel, but the Military waveforms hit a the much  higher QAM  count and throughput in a 3kHz channel and then can increase the bandwidth and shift the PSK carrier up to incrementally increase the throughput.

My friend Dario maintains an excellent easy to understand technical blog on pretty much all the waveforms to be found on HF if one is interested in those subject matters at:

http://i56578-swl.blogspot.com/

<http://i56578-swl.blogspot.com/>/s/ Steve, N2CKH

At 02:21 PM 7/3/2021, you wrote:
R&S  , Useful series of  videos covering  aspects of radio
This video  is applicable to the  VARA modem  coding ,
makes  sense of the  displays  -

73-Graham
g0nbd


This video provides an introduction to the basic concepts of amplitude and phase shift keying (APSK) and quadrature amplitude modulation (QAM).
You-tube link :-

Understanding APSK and QAM <https://www.youtube.com/watch?v=1xGncBvWv6U>


Re: Understanding APSK and QAM Rohde and Schwartz video #VARA

Graham
 

Fun -)

Yes, Ros allays  maintained  designing  digital  modes, was his  Hobby  

I thought  that series  of  videos  posed by R&S , gave a good  over view,  as many  asked
as to  what  exactly the , varying  patterns related to on the  Vara display, 

73-Graham 

 


Monitor function locks up VARA . #VARA

Graham
 
Edited

Monitor function locks up VARA . 
 
Point being  made , ''It appears to only show up in certain pc configurations''
 
Some background, 
 
The  monitor was coded  to  provide  off  air  monitoring ,  but , where as the  modem , each  tx/rx/tx exchange , deal's  only with the  level  in play at the  time  ..  thus , CPU loading  is held at  minimum ....as can be  observed from the  platforms  already running the  modem , in traffic  mode  .. 
 
However, the  monitor  function is  dealing  , in real time , with  scanning  all  16  level variations ,  taking  considerable processing power , far in excess of the  modems  requirement to  pass  traffic ..
 
This  now apperres  to manifest, as  PC build  configurations **,  its not really  something that  requires a  coding fix, but  perhaps  some ''user group''   user  input to  establish the  base line ,  in terms of  processing  power needed  to run the  monitor

..**  As it's a  'large  numeric'  function ,  its possible windows  is  looking to  load the  video  processor , something to investigate , gpu loading ?
 
The inference being ,  a newer pc is required, perhaps ,  more elegant to establish a  base line as to  what works  ?
 
I'm  running,  quite old  now ,  intel  i7  2.6 GHz, 16 g ram  + GT610  video, [legacy driver !] , win10 64 ,  no issue's   

quick check ,   modem  shows 2.5 %  cpu  ,  monitor 'on'  5%  cpu  
 
73-Graham


Re: VARA FM stations and repeaters are not compatible with new VARA FM versions #VARA

Oliver K6OLI
 

There seem to be quite a few on the Canadian side:

Callsign: VA3ETN-10
Frequency: 144.930 MHz

Callsign: VE3ZPW-10
Frequency: 145.090 MHz
Frequency: 446.950 MHz

They look to be about 50-65km from your qth as per QRZ, mostly over water.
Kudos to our Canadian friends!

We recently did an exercise where we connected from mobile field stations (10W, N9TAX antennas) to the Tijuana gateways (25W, omni) from the L.A. area. That was around 220km (135miles).
Audio levels need to be set right with a good antenna 20+ ft in the air and good propagation helps. But it can be done.

73 de Oliver K6OLI


Re: VARA FM stations and repeaters are not compatible with new VARA FM versions #VARA

Andrew O'Brien
 

Olivia , very interesting info. I will have to look in to whether there is anything like that in western New York . Last I checked , there were no FM VARA stations within 150 miles of my QTH. 

Andy


On Aug 7, 2021, at 12:41 PM, Oliver K6OLI <km6dmf@...> wrote:

Hi Andy,

Here in SoCal we have a collaboration project we call the "VARA FM Autobahn". It connects Ventura, Los Angeles and San Diego County ARES groups and CREBC in Tijuana. The goals are to provide area coverage, leverage mutual aid and provide access to HF gateways for potential forwarding of out-of-area messages. Regional communications are important in SoCal, so we do try to provide multiple paths for traffic through VARA FM, Packet, AREDN Mesh and HF.

The Autobahn comprises of 10 gateways, which we leverage by having every user station enabled as a digipeater with SSID -4. Not sure if that counts as a "reasonable" number :-)

Jer K4WOF and his group in Florida have similar VARA FM network supporting their mission.

73 de Oliver K6OLI


Re: VARA FM stations and repeaters are not compatible with new VARA FM versions #VARA

Oliver K6OLI
 

Hi Andy,

Here in SoCal we have a collaboration project we call the "VARA FM Autobahn". It connects Ventura, Los Angeles and San Diego County ARES groups and CREBC in Tijuana. The goals are to provide area coverage, leverage mutual aid and provide access to HF gateways for potential forwarding of out-of-area messages. Regional communications are important in SoCal, so we do try to provide multiple paths for traffic through VARA FM, Packet, AREDN Mesh and HF.

The Autobahn comprises of 10 gateways, which we leverage by having every user station enabled as a digipeater with SSID -4. Not sure if that counts as a "reasonable" number :-)

Jer K4WOF and his group in Florida have similar VARA FM network supporting their mission.

73 de Oliver K6OLI


Re: VARA FM stations and repeaters are not compatible with new VARA FM versions #VARA

Andrew O'Brien
 

Reasonable , not “resonance “ 

Andy


On Aug 6, 2021, at 11:58 AM, Andrew O'Brien via groups.io <andrewobrie@...> wrote:

How is the use of VARA on FM going ? Is there a country where a resonance network of FM stations have developed ? 


Andy


On Aug 6, 2021, at 10:23 AM, Graham <g0nbd@...> wrote:


From  VARA  google  group 

73-G


These VARA FM stations and repeaters are not compatible with new VARA FM versions.
 
I would recommend update to a new VARA FM version as soon as be possible to accept new connections


Outdated VARA FM stations.jpg


Re: Understanding APSK and QAM Rohde and Schwartz video #VARA

ALE
 


Hi Graham,

QAM is fun, working to develop Military data modem and ALE serial tone modem QAM waveforms.

In my attached photo the QAM waveform in the constellation display is an MS110B offering, going into MS110C/D Appendix D and 4G ALE get even more complicated, I have not made it to 256-QAM yet, the Appendix waveforms and 3G ALE are in my near future however.

The SCS P4 serial tone modem stops at 32-QAM in less than a 3kHz channel, but the Military waveforms hit a the much  higher QAM  count and throughput in a 3kHz channel and then can increase the bandwidth and shift the PSK carrier up to incrementally increase the throughput.

My friend Dario maintains an excellent easy to understand technical blog on pretty much all the waveforms to be found on HF if one is interested in those subject matters at:

http://i56578-swl.blogspot.com/

/s/ Steve, N2CKH


At 02:21 PM 7/3/2021, you wrote:
R&S  , Useful  series of  videos covering  aspects of radio
This video  is applicable to the  VARA modem  coding ,
makes  sense of the  displays  -

73-Graham
g0nbd


This video provides an introduction to the basic concepts of amplitude and phase shift keying (APSK) and quadrature amplitude modulation (QAM).
You-tube link :-

Understanding APSK and QAM


Re: VARA FM stations and repeaters are not compatible with new VARA FM versions #VARA

Andrew O'Brien
 

How is the use of VARA on FM going ? Is there a country where a resonance network of FM stations have developed ? 


Andy


On Aug 6, 2021, at 10:23 AM, Graham <g0nbd@...> wrote:


From  VARA  google  group 

73-G


These VARA FM stations and repeaters are not compatible with new VARA FM versions.
 
I would recommend update to a new VARA FM version as soon as be possible to accept new connections


Outdated VARA FM stations.jpg


VARA FM stations and repeaters are not compatible with new VARA FM versions #VARA

Graham
 


From  VARA  google  group 

73-G


These VARA FM stations and repeaters are not compatible with new VARA FM versions.
 
I would recommend update to a new VARA FM version as soon as be possible to accept new connections


Outdated VARA FM stations.jpg


new SW Radiogram program available

 

Hello to all the digital folks out there.
 
A new program for the Shortwave Radiogram broadcasts has now been posted on the SW Radiogram website.
 
If you're new to decoding digital, this is a pretty nice way to get your feet wet. You can use your desktop or laptop, or you can use an Android device such as a smartphone or tablet. You can find links to the SW Radiogram website, software for decoding, and wiki articles with extensive details and help at: http://www.udxf.nl/events.html.  
 
If you'd like to see a list of web receivers (which are often reported as being used), receiver, transceiver and SDR applications and more, take a look at the SW Radiogram gateway at https://wiki.radioreference.com/index.php/Shortwave_Radiogram_Gateway
 
Help is also available on Facebook and Twitter. The SW Radiogram website has the links. 
 
Radio Northern Europe International also uses digital modes during its broadcasts. The August schedule hasn't been announced as of this writing.  
See https://rnei.org/ for more information.
   
Here's hoping for good propagation&nbs


new SW Radiogram program available

 

Hello to all the digital folks out there.
 
A new program for the Shortwave Radiogram broadcasts has now been posted on the SW Radiogram website.
 
If you're new to decoding digital, this is a pretty nice way to get your feet wet. You can use your desktop or laptop, or you can use an Android device such as a smartphone or tablet. You can find links to the SW Radiogram website, software for decoding, and wiki articles with extensive details and help at: http://www.udxf.nl/events.html.  
 
If you'd like to see a list of web receivers (which are often reported as being used), receiver, transceiver and SDR applications and more, take a look at the SW Radiogram gateway at https://wiki.radioreference.com/index.php/Shortwave_Radiogram_Gateway
 
Help is also available on Facebook and Twitter. The SW Radiogram website has the links. 
 
Radio Northern Europe International also uses digital modes during its broadcasts. The August schedule hasn't been announced as of this writing.  See https://rnei.org/ for more information.
   
Here's hoping for good propagation 


new SW Radiogram program available

 

Hello to all the digital folks out there.
 
A new program for the Shortwave Radiogram broadcasts has now been posted on the SW Radiogram website. 
 
If you're new to decoding digital, this is a pretty nice way to get your feet wet. You can use your desktop or laptop, or you can use an Android device such as a smartphone or tablet. You can find links to the SW Radiogram website, software for decoding, and wiki articles with extensive details and help at: http://www.udxf.nl/events.html.  
 
If you'd like to see a list of web receivers (which are often reported as being used), receiver, transceiver and SDR applications and more, take a look at the SW Radiogram gateway at https://wiki.radioreference.com/index.php/Shortwave_Radiogram_Gateway
 
Help is also available on Facebook and Twitter. The SW Radiogram website has the links. 
 
Radio Northern Europe International has announced its new schedule for program 19.  
See https://rnei.org/2021/06/30/radio-northern-europe-international-show-19-announcement-post/
 
Here's hoping for good propagation 


Re: Opera QSO party running on 7038

Graham
 



Reliable dx spots , [ actual power = 50% carrier , dur to  duty cycle ]

18:02   7038 SV1XV de SV8RV Op2 155 mi -5 dB F:0% in Zakynthos(Zante) isl.GREECE 1523,4 Hz with 25w + Vertical
18:02   7038 SV1XV de RX3DHR Op2 1357 mi -10 dB F:10% in  1498,0 Hz with 25w + Vertical
18:02   7038 SV1XV de G0NBD Op2 1655 mi -22 dB F:5% in Liverpool - 1502.9 Hz with 25w + Vertical
18:02   7038 SV1XV de VK3KCX Op2 -27 dB F:3% in Melbourne 1499.0 Hz

18:04   7038 RX3DHR de SV8RV Op2 1445 mi -17 dB F:19% in Zakynthos(Zante) isl.GREECE 1524,4 Hz with 10w + AVT4
18:04   7038 RX3DHR de SV1XV Op2 1357 mi -12 dB F:20% in Athens 1501.0 Hz with 10w + AVT4
18:04   7038 RX3DHR de G0NBD Op2 1674 mi -21 dB F:13% in Liverpool - 1503.9 Hz with 10w + AVT4


Re: Opera QSO party running on 7038

Graham
 

7038  -  ALL de VK3KCX (Australia): Beacon Op2 every 12:18 in Melbourne 25w + Dipole

Something  complete different ?,  automated   qso  system .. adif listed  as well 

Running  now anyone wants a  try to  VK , 7 open ww  at moment 

last night ,  Via web sdr PERTH vk 23:52 7038 G0NBD de G8FZKSDR Op2 9167 mi -23 dB F:3% in vk 1502.0 Hz

73-Graham
g0nbd


new SW Radiogram program available

 

Hello to all the digital folks out there.
 
A new program for the Shortwave Radiogram broadcasts has now been posted on the SW Radiogram website. 
 
If you're new to decoding digital, this is a pretty nice way to get your feet wet. You can use your desktop or laptop, or you can use an Android device such as a smartphone or tablet. You can find links to the SW Radiogram website, software for decoding, and wiki articles with extensive details and help at: http://www.udxf.nl/events.html.  
 
If you'd like to see a list of web receivers (which are often reported as being used), receiver, transceiver and SDR applications and more,  take a look at the SW Radiogram gateway at https://wiki.radioreference.com/index.php/Shortwave_Radiogram_Gateway
 
Help is also available on Facebook and Twitter. The SW Radiogram website has the links. 
 
Radio Northern Europe International has announced its new schedule for program 19.  
See https://rnei.org/2021/06/30/radio-northern-europe-international-show-19-announcement-post/
 
Here's hoping for good propagation 


new SW Radiogram program available

 

Hello to all the digital folks out there.
 
A new program for the Shortwave Radiogram broadcasts has now been posted on the SW Radiogram website. 
 
If you're new to decoding digital, this is a pretty nice way to get your feet wet. You can use your desktop or laptop, or you can use an Android device such as a smartphone or tablet. You can find links to the SW Radiogram website, software for decoding, and wiki articles with extensive details and help at: http://www.udxf.nl/events.html.  
 
If you'd like to see a list of web receivers (which are often reported as being used), receiver, transceiver and SDR applications and more, take a look at the SW Radiogram gateway at https://wiki.radioreference.com/index.php/Shortwave_Radiogram_Gateway
 
Help is also available on Facebook and Twitter. The SW Radiogram website has the links. 
 
Radio Northern Europe International has announced its new schedule for program 19.  
See https://rnei.org/2021/06/30/radio-northern-europe-international-show-19-announcement-post/
 
Here's hoping for good propagation 


TrueTTY 3.10 beta and new PS2x5 mode

Sergei Podstrigailo
 

Hello All,

A new experimental PS2x5 mode is proposed for testing:.

https://www.dxsoft.com/truettyb.zip

TrueTTY Versions History

V3.10
An experimental mode PS2x5 has been implemented.
It is a simple and robust protocol based on FSK2 with strong
FEC based on the Reed-Solomon RS(31,15) code.
The data rate is approximately 0.36 of the baud rate.
It is recommended to choose the frequency shift equal to or twice the
baud rate. Recomended starting parameters for rather bad conditions
are 25 Bd with 50 Hz shift.

===

The protocol details:

PS2x5 is an experimental streaming protocol over FSK2

It can be considered an improved version of AMTOR-FEC (SITOR-B, NAVTEX) with a more
powerful FEC based on Reed-Solomon code RS(31,15) and with much more robust error control.

The probability of receiving a corrupted data chunk is practically eliminated -
a data block (7 bytes) is either received without errors or it is not received at all.

Block numbering ensures that if less than eight blocks are not received that
information about the number of missed characters is also preserved
(unaccepted characters are replaced by underscores).

The full set of single-byte characters (0...255) is supported.
During text exchange a character with code 0 is used
as a non-printable character (it is transmitted when no new data from the operator is received).

The protocol is insensitive to spectrum inversion
(i.e . USB or LSB selection when the signal is forming as AFSK).

The data rate is about 0.36 of the baud rate.
That is, at a baud rate of 25 bauds data rate will be 9 bps,
i.e. some over 60 LPM.

This is why the variant "25 Bd Speed/50 Hz Shift" is proposed as a starting point
for "medium-bad" propagation conditions.

When the baud rate is changed it is recommended to choose the frequency shift equal
to the speed or twice as much.

The protocol details:

Transmitted text is divided into blocks of seven bytes.
A four-bit block number is appended to the each block.
The first eight blocks of transmission are numbered as 8...15,
the next blocks are numbered cyclically as 0...7.

The seven bytes of data and the block number are packed into 12 five-bit symbols,
then 15 bits (three five-bit symbols) of CRC are added to them.

Then 16 check symbols of the Reed-Solomon code are added to the block. So up to eight
erroneous symbols in a each block can be corrected.

Then the resulting block of 31 five-bit symbols is transmitted sequentially
(high bit of a symbol first) using differential FSK2-modulation.

0 is encoded by frequency shift, 1 is the same frequency.

===

Samples of signal in wav-files and the program for generation:

https://www.dxsoft.com/download/ps2x5samples.zip

===

If you didn't buy TrueTTY :-) , this demo-key can be used till 31 July:


ABC(OGAOAKBFDCGANIKBJDEBAMMAAEBEMMEAECAIMAAMAIEJCDHGCNMMBKDF
GEOEJBCDACIOMLBABEEKMELJHDADOGELBJBBDCPAIAFABDMGIMAKBHDMGAOI
KBBDEGICIACGEGIMHJHCOGPAAEADFAOEJJCDEGEBEAJKDEHONMBJHDEFONED
JADIHJBAEAEFEOEJJJDIGONALBCDKAEKAFBKCJFEBIBBECFGCNMJBEDEHEBO
BAMAIJEJBDDEHEBMDBHDEFONAMBFACFHCAGADFGMIMJCDFGMNICMJAMAOOAA
BOKEKBCDEHANICILCPGEOMKBDCCHKMEMBFAGEONILBKDKAGIAKJADCHGOEJB
KDKAKKMMJCDCHJBAGAGECNALJCDKAGIMLBGDPGEOICAICJGIOMIBEDKAGKEK
BNDFGEBMEBKDJHPCACACEGNMJFNAEBIDJADNGJCACILKACIJCIGCNOPBEAEK
EJBLDFGNHACAKAAKEMAFAAFEGICAICDDEBAEBKBKAAKENAFAAFMGICAICHDE
BAEBMBKAAKEOAFIAAA/2056596104)CBA
*Demo07m21y *TrueTTY*



--
Best regards,
Sergei


Understanding APSK and QAM Rohde and Schwarz video #VARA

Graham
 

Understanding APSK and QAM Rohde and Schwarz video


R&S  , Useful  series of  videos covering  aspects of radio 
This video  is applicable to the  VARA modem  coding , 
makes  sense of the  displays  - 

73-Graham
g0nbd


This video provides an introduction to the basic concepts of amplitude and phase shift keying (APSK) and quadrature amplitude modulation (QAM).
You-tube link :-

Understanding APSK and QAM


new SW Radiogram program available

 

Hello to all the digital folks out there.
 
A new program for the Shortwave Radiogram broadcasts has now been posted on the SW Radiogram website. 
 
If you're new to decoding digital, this is a pretty nice way to get your feet wet. You can use your desktop or laptop, or you can use an Android device such as a smartphone or tablet. You can find links to the SW Radiogram website, software for decoding, and wiki articles with extensive
details and help at: http://www.udxf.nl/events.html.  
 
If you'd like to see a list of web receivers (which are often reported as being used), receiver, transceiver and SDR applications and more, take a look at the SW Radiogram gateway at https://wiki.radioreference.com/index.php/Shortwave_Radiogram_Gateway
 
Help is also available on Facebook and Twitter. The SW Radiogram website has the links. 
 
Radio Northern Europe International has announced its new schedule for program 19.  
See https://rnei.org/2021/06/30/radio-northern-europe-international-show-19-announcement-post/
 
Here's hoping for good propagation  

101 - 120 of 51634