Date   

Contestia 16/250 now available with RSID in fldigi and MULTIPSK

Gerry Lawlor
 

Hi Folks
Having spent some time recently using Contestia 16/250 on 40m with others it's apparent that it's a good mode for marginal conditions and at an acceptable speed.  Comparison with other modes has been unfavourable during our tests around 2100Z between Europe and the near US.  Jim AJ8S has been using this mode successfully over a longer period on the path from Ohio to VK6 on 40m.  
Up until  now there was no ready method of setting this mode up other than by using the Config Modem menu in fldigi.  Also, no RSID was available for it.  However that has now changed.   Patrick F6CTE has incorporated Contestia 16/250 into the latest version of MULTIPSK and assigned an RSID to it.  Dave W1HKJ has now incorporated it into the latest version of fldigi -version 4.1.16.01. 
It would be nice to see others using this mode and availing of the superior S/N performance, which at -15 dB is 3 dB superior to e.g. Olivia 4-250 at -12 dB for the same ~20 WPM.   Generally, we play around 7068 kHz CF USB  at approximately 21Z.   Power levels of 200-300W to wire antennas have worked well.   A bandwidth of 300 Hz is very effective on RX. Of course,  there is no reason not to use the other conventional frequencies for digi modes now that an RSID has been assigned. 
Hoping to see some activity in this "new" mode.
73
Gerry EI9FV 


VARA HF v4.0.6 PTT for RA Board interface #VARA

Graham
 
Edited

VARA HF v4.0.6  PTT for RA Board interface

From Vara user group 

Addition added to the VARA modem  , supporting the  RA  interface board
notes, this board is  not  supported by winlink , hence the  direct address
option , 

[on air modem remains  unchanged]

73-Graham
g0nbd

RA board   web link 


VARA HF RA Board.jpg


Re: Build a Long-Distance Data Network Using Ham Radio - IEEE Spectrum

Siegfried Jackstien
 

see also

https://hnap.de/assets/pdf/Presentation%20-%20HNAP4PlutoSDR.pdf


Am 31.10.2020 um 18:25 schrieb Rud K5RUD:

That is interesting. I've wondered why the ISM targeted radios hadn't been used by us. There may even be some 9600 bps packet version that would work on 2m. Don't have the hardware skills to attempt a project so never looked that closely the radios. The NPR might also find us on the 33 cm band. Think I've seen ISMs in that band.


-73 -
Rud Merriam K5RUD
Mystic Lake Software

On 10/30/20 10:55 PM, Andrew O'Brien wrote:
https://spectrum.ieee.org/geek-life/hands-on/build-a-longdistance-data-network-using-ham-radio?fbclid=IwAR23qOqAH2yJ7SR-Fs2FVjy2Q3eGlazRcRyfdiAWmp5yG7RyYr4fqjUje7A


Andy







Re: Build a Long-Distance Data Network Using Ham Radio - IEEE Spectrum

Siegfried Jackstien
 

here in dl they develop a similar thingy around a pluto

high speed access to ham radio network without line of sight (70cm used here but all higher bands are possible up to 6 gig)

a pluto ... an amp ... and a high speed rx tx switching device (relays are too slow) ... (its an rf diode switching ic used from skyworks)

that is user end

base station running fullduplex with filters (pluto amp and filters)

infos here on github

https://github.com/HAMNET-Access-Protocol/HNAP4PlutoSDR

greetz sigi dg9bfc

ps pluto can use any band rx and tx so maybe you can work without filters but two bands

Am 31.10.2020 um 18:25 schrieb Rud K5RUD:

That is interesting. I've wondered why the ISM targeted radios hadn't been used by us. There may even be some 9600 bps packet version that would work on 2m. Don't have the hardware skills to attempt a project so never looked that closely the radios. The NPR might also find us on the 33 cm band. Think I've seen ISMs in that band.


-73 -
Rud Merriam K5RUD
Mystic Lake Software

On 10/30/20 10:55 PM, Andrew O'Brien wrote:
https://spectrum.ieee.org/geek-life/hands-on/build-a-longdistance-data-network-using-ham-radio?fbclid=IwAR23qOqAH2yJ7SR-Fs2FVjy2Q3eGlazRcRyfdiAWmp5yG7RyYr4fqjUje7A


Andy







Re: Build a Long-Distance Data Network Using Ham Radio - IEEE Spectrum

Rud K5RUD
 

That is interesting. I've wondered why the ISM targeted radios hadn't been used by us. There may even be some 9600 bps packet version that would work on 2m. Don't have the hardware skills to attempt a project so never looked that closely the radios. The NPR might also find us on the 33 cm band. Think I've seen ISMs in that band.


-73 -
Rud Merriam K5RUD
Mystic Lake Software


Re: Inexpensive Multi-Band Receiver?

Wa4kfz
 

I think most of the recommendations for a SDR were also based on part of your initial comment:

“Something you might use for an iGate but not fixed frequency.”

By ‘not fixed frequency’ people assumed you were talking about a receiver that could be tuned without manual operator intervention (i.e., having to manually tune the radio if you change modes or frequency). 

Regardless of single conversion, double conversion, etc. what you want in a receiver is good rejection of undesired signals as well as the ability to work well in high dynamic range environments. Once the DSP gets overloaded, DSP “math” falls apart rapidly and signal processing fails. 

73,

Mark WA4KFZ 



On Oct 31, 2020, at 1:30 PM, Graham <g0nbd@...> wrote:


Rud,

SDR- May be not quite ,  its based on a  single  chip ,  with  analog  front end , mixers , then  converts to 
digital to  take care of the  filtering  , decoding etc , very much the  same as any of the  dongle based  sdr systems
unless you  pick up quite a  old  RX, the  analogue front end  >> digital  back  end  will  be the  general layout 

As stand alone Rx , gets good  reports  ,  only possible down side for  data could be the  need to  use the  recovered audio from the  set, as previous, elimination, of as may items in the  signal path, will  reduce distortion , drift and improve  s/n 

73-Graham


<dummyfile.0.part>


Re: Inexpensive Multi-Band Receiver?

Graham
 


Rud,

SDR- May be not quite ,  its based on a  single  chip ,  with  analog  front end , mixers , then  converts to 
digital to  take care of the  filtering  , decoding etc , very much the  same as any of the  dongle based  sdr systems
unless you  pick up quite a  old  RX, the  analogue front end  >> digital  back  end  will  be the  general layout 

As stand alone Rx , gets good  reports  ,  only possible down side for  data could be the  need to  use the  recovered audio from the  set, as previous, elimination, of as may items in the  signal path, will  reduce distortion , drift and improve  s/n 

73-Graham



Build a Long-Distance Data Network Using Ham Radio - IEEE Spectrum

Andrew O'Brien
 


Re: Inexpensive Multi-Band Receiver?

Rud K5RUD
 

Thanks for the suggestion. You're the first one not to suggest an SDR! Appreciate it.


-73 -
Rud Merriam K5RUD
Mystic Lake Software

On 10/30/20 9:33 AM, Thomas Giella wrote:
The Tecsun PL-880 is a very good LW, MW, SW portable receiver for around $150.00 U.S. It has good selectivity, good sensitivity, multiple bandwidth filters and DSP noise reduction. Universal Radio sells it.

73,
Thomas W4HM


Re: Inexpensive Multi-Band Receiver?

Thomas Giella <thomasfgiella@...>
 

The Tecsun PL-880 is a very good LW, MW, SW portable receiver for around $150.00 U.S. It has good selectivity, good sensitivity, multiple bandwidth filters and DSP noise reduction. Universal Radio sells it.

73,
Thomas W4HM


Re: Inexpensive Multi-Band Receiver?

Graham
 
Edited

Rud,

Really depends  on your  intended use , if by digital you  mean the  more normal  HF  beacon  and data  modes ,  any of the  cheap  dongle based set up's  should work  fine , $ no longer equate to  performance , some of the  web-sdr's  are  using  simple $10  dongles as the  rx  heads  , a simple  rtl  dongle will  tune  20 to 1500  MHz , with 2 MHz window 

Though  not my preferred option**, any of the  up converters , gives  full  audio to  Ghz  , for not  very much 

** signal path  is  then   
HF>>VHF>>VHF>>HF>>A/D > pc   , two  mixing  stages and various  amp's, where  as 
direct conversion 
 HF>>A/D  > pc 

The latest batch of low band modes , have stability requirements beyond the  more simple set up's , progress ? may be not, as the effective RX numbers are reduced , but each to his own,  these  require additional  expenditure on  high stability reference oscillators and equipment that  accepts  external  reference inputs 

73-Graham
g0nbd


Re: Inexpensive Multi-Band Receiver?

Rud K5RUD
 

Thanks for the comments. Should have mentioned I'm on a Linux system. There is SDR for it. Still considering a stand-alone RX.


-73 -
Rud Merriam K5RUD
Mystic Lake Software

On 10/28/20 2:58 PM, James Clark wrote:
Another vote for SDR Play - perfect for your requirement.






Re: Inexpensive Multi-Band Receiver?

James Clark
 

Another vote for SDR Play - perfect for your requirement.


Re: Inexpensive Multi-Band Receiver?

Ralph Mowery
 

Look in the the SDR Play receiver module.  You do have to hook it to a computer but the software is often free to do many things with it.  It will cover from the audio frequencies to 2 ghz for only $ 120.


Ralph ku4pt





On Wednesday, October 28, 2020, 01:08:06 PM EDT, Rud K5RUD <rud.merriam@...> wrote:


Recommendations for an inexpensive multi-band receiver to use as input to my computer for digital signals. Something you might use for an iGate but not fixed frequency.

--

-73 -
Rud Merriam K5RUD
Mystic Lake Software

_._
_._,_._,_


Inexpensive Multi-Band Receiver?

Rud K5RUD
 

Recommendations for an inexpensive multi-band receiver to use as input to my computer for digital signals. Something you might use for an iGate but not fixed frequency.

--

-73 -
Rud Merriam K5RUD
Mystic Lake Software


Re: AMTOR?

Rick Muething
 

Graham/All,

Digital modes have evolved much over the past 20 years.  There is however a basic underlying limit (Initially described by AT&T engineer Claude Shannon  in a landmark 1948 paper that proposed (which has now been proven) there is a basic limit to how much information can be sent within a given channel with a given amount of noise... and this is limited to the Energy per bit (Watts x symbol length divided by bits/symbol) divided by the Noise (No).  This is true whether we are talking about Deep space probes or HF Ionospheric propagation.  What has changed is better DSP (digital signal processing) and error correcting codes that allow us to more closely approach that limit.  Excellent examples today on HF are VARA (2300 Hz or 500 Hz bw) and Pactor 4 (1900 Hz bw). Pactor 4 is one of the first amateur mode to use dynamic channel equalization that improves its throughput dramatically in multi-path propagation common on HF.  If interested in some comparisons  of popular digital modes on HF and VHF/UHF see the write-up at  https://winlink.org/content/ionos_simulator

73,

Rick Muething, KN6KB


On 10/27/2020 6:33 PM, Graham wrote:
I dont think its a  mode  / use problem,  I used to  have  regular contacts with the  USA  east  on 7  MHz using  amtor , long back, 
running  round  240 watts  carrier power , one guy even  asked me 'which state liverpool was in'  , unexpected  dx ..

the new  generation  of  data modes , reduced the  power needs to something like  25  watts  , a good  + 10 db gain , to  do the  same thing 

That was when the  bands where in  good  condition , I do  know from  tests  on 476 KHz , the  latest vara HF modem is  as  sensitive 
if not  more so, than the slowest  olivia mode , but  many times  faster and provides a  amtor like  fast  turn  round  qso  , using the  chat  module , interesting  test with  station  200  miles  south  of me , on MF  

73 -Graham
g0nbd


Re: Autex Packet Collisions?

Patrick Lindecker
 

Hello Tony,

In an Autex net, each "Slave" station has its frequency. So there are no collisions between slaves, but a collision with the Master frame is possible.

Here is a diagram of the different possible topologies, on a bandwidth of 500 Hz around the Master frequency (MF), for Autex 4:
One Slave:
M<----->S1 (on the SF1 frequency=MF-167 Hz)

Two Slaves:
M <----->S1 (on the SF1 frequency=MF-167 Hz)
M <----->S2 (on the SF2 frequency=MF Hz)

Three Slaves (maximum):
M <----->S1 (on the SF1 frequency=MF-167 Hz)
M <----->S2 (on the SF2 frequency=MF)
M <----->S3 (on the SF3 frequency=MF+167 Hz)

Collisions will likely increase with the number of participating stations so I was wondering if Autex any has data carrier detection or some sort of >busy channel method used to prevent this?
No there is no carrier detection. The protocol permits to avoid collision, as far as possible...
The main tool used is the RS ID (Reed-Solomon Identifier) which is used to locate in time and frequency the Master message, for present and future Slaves.

73
Patrick



-----Message d'origine-----
De : main@digitalradio.groups.io [mailto:main@digitalradio.groups.io] De la part de Tony
Envoyé : mardi 27 octobre 2020 21:58
À : main@digitalradio.groups.io
Objet : [digital-mode-radio] Autex Packet Collisions?

Patrick:

I think you've done an incredible job developing Autex. I wanted let you know that I did notice a few packet collisions while participating in a round table which inevitably happens when one or more stations transmit at the same time.

Collisions will likely increase with the number of participating stations so I was wondering if Autex any has data carrier detection or some sort of busy channel method used to prevent this?

I plan on testing the mode PC-to-PC to see if I can recreate the collisions I observed on air.

Thanks,

Tony -K2MO







---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus


Re: AMTOR?

Graham
 

I dont think its a  mode  / use problem,  I used to  have  regular contacts with the  USA  east  on 7  MHz using  amtor , long back, 
running  round  240 watts  carrier power , one guy even  asked me 'which state liverpool was in'  , unexpected  dx ..

the new  generation  of  data modes , reduced the  power needs to something like  25  watts  , a good  + 10 db gain , to  do the  same thing 

That was when the  bands where in  good  condition , I do  know from  tests  on 476 KHz , the  latest vara HF modem is  as  sensitive 
if not  more so, than the slowest  olivia mode , but  many times  faster and provides a  amtor like  fast  turn  round  qso  , using the  chat  module , interesting  test with  station  200  miles  south  of me , on MF  

73 -Graham
g0nbd


Autex Packet Collisions?

Tony
 

Patrick:

I think you've done an incredible job developing Autex. I wanted let you know that I did notice a few packet collisions while participating in a round table which inevitably happens when one or more stations transmit at the same time.

Collisions will likely increase with the number of participating stations so I was wondering if Autex any has data carrier detection or some sort of busy channel method used to prevent this?

I plan on testing the mode PC-to-PC to see if I can recreate the collisions I observed on air.

Thanks,

Tony -K2MO


Starting daily 10m PSK activity half-hour

Andrew O'Brien
 

I propose drumming up some PSK31 activity on 10m now that the band is opening up more often . 28120 USB is a good frequency for all those licensed for that band .

I suggest we set up a “4PM PSK Activity Half Hour” . If it is 4PM where you are , get on 10m and CQ or just answer a CQ”. I will be there this evening 4PM eastern USA time .

It will be interesting to see what you can hear when it’s 4PM 3-4 thousand miles east of you on some days .

Andy

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