Date   

vARIM Messaging Program for VARA HF Modem - version 1.1

Bob NW8L
 

Hello,
 
Introducing a new member of the ARIM family, vARIM, adapted to use the VARA HF modem. Version 1.0 is available here:
 
https://www.whitemesa.net/varim/varim.html
 
on the vARIM Help page.
 
Files are also available in the Files area at the arim-ham Groups.io group:
 
https://groups.io/g/arim-ham/files
 
vARIM is a peer-to-peer messaging and file transfer for HF bands. It's similar to gARIM, but with a reduced feature set because VARA doesn't support "unconnected" transmissions like ARDOP does. For instance, there is no beaconing. All vARIM data transfers are made during an ARQ session. It will run on Linux, Raspberry Pi, Cygwin/X on Windows and also Windows Subsystem for Linux (WSL) on Windows 10. The VARA modem runs only on Windows computers, but vARIM can run in Cygwin/X or WSL on the Windows computer, which is convenient. Alternatively, you can run vARIM on a Linux or RPi computer and attach it to a VARA modem instance running on a Windows computer in the same local area network.
 
For Linux OS, the binary distributions are for Ubuntu 18.04 and derivatives like Linux Mint 19.x only. It's best to compile vARIM from source code to avoid library versioning problems. It's easy, instructions are found in the INSTALL file included in the source distribution (with instructions for Fedora 28 and derivatives, and for Cygwin/X too).
 
Be aware of some differences in the configuration file format - an existing gARIM config file (garim.ini) can't be used without modification. The details are found in the Help document linked above.
 
vARIM works with new VARA HF version 4 which introduces a robust 500Hz ARQ bandwidth option. vARIM allows you to specify which bandwidth to use in the .ini file, or as a choice in the "ARQ Connect" dialog (500 or 2300 Hz).
 
To key the rig, if VOX isn't suitable, vARIM supports hardware PTT using serial port RTS or DTR signals. This works on Linux, RPi, Cygwin/X and WSL using built in serial ports or USB-to-Serial converter cables. PTT setup details are found in the Help page. 
 
I have a station running VARA HF version 4.0.3 on (dial) 7.085 MHz that's available for testing. The station call sign is NW8L and it will be configured for operation at the 500Hz bandwidth. It might be QRT from time to time if thunderstorms are in the area (near Albuquerque, NM). At NW8L vARIM is running in WSL on the same Windows 10 laptop that hosts the VARA HF modem. The audio interface is a USB sound card connected to line in and line out jacks on the rig. The rig is keyed using vARIM's hardware PTT (DTS) over a USB-to-Serial converter cable between computer and rig.
 
If anyone using VARA HF has time to test vARIM I would be interested in your results and bug reports. If you install vARIM, try connecting to NW8L on (dial) 7.085MHz and sending me a message!
 
73,
Bob NW8L
 


Whats new in VARA 4 ? #VARA #qrp

Graham
 
Edited

Whats new in VARA 4 , live as from  1 July 

Faster high rate  transfer and lower 
s/n weak signal performance 

Completely re-worked protocol 

 2.3 KHz b/w : 16  speed levels

New 500 Hz B/W mode : 13 speed levels

Mixed  B/W  connections  possible -winlink - bpq

Unlicensed  access remain at MFSK  2.3 K  175   /  500 Hz 88 Net rate 

 V4 deploys  a all new re configured, non backward compatible
protocol ,providing a  faster  and streamlined  Data /Ack  sequence 
with  new symbol rates / carrier  configurations , supporting , 
higher transfer rates and  enhanced weak  signal  performance to
that  expected of  conventional chat-mode's  

Level 16 , of the  2.3K mode, provides  a net rate  of 7050  BPS
with  49 on air  carriers , running at symbol rate  of  42 Baud 
the  49 carrier  modem is  engaged at level 10  with  2011 BPS 
in keeping with  HF channel compatibility , none of the  speed
levels  deploy symbol rates  over  94 B,  round ''50   being the  norm

The new 500 B/W mode  reaches a  maximum  throughput of 1534 BPs
with 11 carriers , 42  baud symbol  rate, making  for a  very  robust connection .
primarily provided to  allow  use in the  narrowband  mail  box  areas , in association
with  email/file  transfer . 

Interestingly  level  1 , 2.3 K and level 1  500 Hz b/w   is set  at  18 BPs
at the  same  s/n  ratio, for  each  mode ...In discussions round s/n  ,
the  new  low  sensitivity levels/data  rate is felt to 
exceed  that  offered by the  OLIVIA data  mode , which, in terms
of  payload delivery  , offers a very high level 
of  'link completion' under  adverse conditions,  

CHAT users, are  provide  , only with  access  to the  2.3 K b/w mode , winlink 
or BPS is required to access  the  500  version , however,  the  2.3  modem now
provides close or  if not  below the  noise  live  qso  and file  transfer . this coupled with
the off air  'monitor option' , gives reasonable round table  performance, fast arq , providing
error free conversation at  amtor  rates , at weak signal levels, without the detection  and 
lock time  delays of conventional 'robust'  'chat' modes , 

QRP  , Unregistered the  modem  is limited to  phase continuous  MFSK,
  providing  compatibility with  non lienera TX , eg class C, E/D  , OFDM require's
linear path . providing an alternative  to  Olivia dx qso's ,  noting  [Olivia has a  phase  component to
the modulation  waveform and requires a  Linera  TX path]   .....Noting  of course,  Vara 
requires a full linear Tx&Rx  path , once the  speed  ranges , engauge the  OFDM modem
registered or  not,  the  QRP aspect remains  available  
l

MF/MF-Ecomm's  The  500Hz  Bw  meets data B/W  requirement's **  for the  MF band , and could provide E-COMM's 
making  use of the  enhanced weak  signal  aspect , MFSK  2.3 K  175   /  500 Hz 88 Net rate 
its unusual for  High power MF Tx to  be  linear , but , if  so, then  full  use could be  made .
noting,  there  is no facility to  change the  TX tone mid band , perhaps not  so much of a issues these  days 

** May change  region to region, 

   Modem  rate / level  chart 





Mixed mode connection, accessed  via  option  choices  in the  
modem set up , where possible, gateway connection at  2.3 K
is advised , to  minimise access time . 

The 500<->2300 gateway compatibility option can be used by Sysops to 
monitor  both,  2300 and 500  simultaneously. the modem will detect 
and configure to the  calling  station 





WINLINK    

The modem  requires a  minimum  Dwell  time  of  4 seconds  , when  using the  TRI-Mode  
function 

VARA is  now  included in the  Forwarding  facility 


VARA  FM , VARA  9600 , VARA SAT  all  remain as  was 


73 -Graham
g0nbd


Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Chiefsfan2
 

Ok Andy how about this weekend?

On Jul 1, 2020, 17:50 -0500, Andrew OBrien <k3ukandy@...>, wrote:
I’ll experiment with it 

Andy K3UK 


On Jul 1, 2020, at 6:40 PM, Chiefsfan2 <chiefsfan2@...> wrote:


Anyone on the group want to experiment with hfpager?
On Jun 5, 2020, 03:24 -0500, Kristoff Bonne <kristoff@...>, wrote:
Serge,


On 3/06/2020 19:31, Sergei Podstrigailo wrote:
KB> I can't speak for John, but I think the question was about a port
of the
KB> complete stack (encoder and decoder) to linux single-board computer or a
KB> MCU or MCU/FPGA.

We are working on full "Hardware pager" with embedded transceiver, STM32 controller and e-Ink display too...
Versions for small Linux systems probably will be made also, but some later...
I hope that's will not be a 'just install and use'  box. :-(


These kind of devices almost killed the spirit of amateur-radio.
Thankfully the maker/hacker-community came to save us.


73
kristoff - ON1ARF




Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Chiefsfan2
 

Ok Andy, how does this weekend look for you?

On Jul 1, 2020, 17:50 -0500, Andrew OBrien <k3ukandy@...>, wrote:
I’ll experiment with it 

Andy K3UK 


On Jul 1, 2020, at 6:40 PM, Chiefsfan2 <chiefsfan2@...> wrote:


Anyone on the group want to experiment with hfpager?
On Jun 5, 2020, 03:24 -0500, Kristoff Bonne <kristoff@...>, wrote:
Serge,


On 3/06/2020 19:31, Sergei Podstrigailo wrote:
KB> I can't speak for John, but I think the question was about a port
of the
KB> complete stack (encoder and decoder) to linux single-board computer or a
KB> MCU or MCU/FPGA.

We are working on full "Hardware pager" with embedded transceiver, STM32 controller and e-Ink display too...
Versions for small Linux systems probably will be made also, but some later...
I hope that's will not be a 'just install and use'  box. :-(


These kind of devices almost killed the spirit of amateur-radio.
Thankfully the maker/hacker-community came to save us.


73
kristoff - ON1ARF




Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Andrew OBrien
 

I’ll experiment with it 

Andy K3UK 


On Jul 1, 2020, at 6:40 PM, Chiefsfan2 <chiefsfan2@...> wrote:


Anyone on the group want to experiment with hfpager?
On Jun 5, 2020, 03:24 -0500, Kristoff Bonne <kristoff@...>, wrote:
Serge,


On 3/06/2020 19:31, Sergei Podstrigailo wrote:
KB> I can't speak for John, but I think the question was about a port
of the
KB> complete stack (encoder and decoder) to linux single-board computer or a
KB> MCU or MCU/FPGA.

We are working on full "Hardware pager" with embedded transceiver, STM32 controller and e-Ink display too...
Versions for small Linux systems probably will be made also, but some later...
I hope that's will not be a 'just install and use'  box. :-(


These kind of devices almost killed the spirit of amateur-radio.
Thankfully the maker/hacker-community came to save us.


73
kristoff - ON1ARF




Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Chiefsfan2
 

Anyone on the group want to experiment with hfpager?

On Jun 5, 2020, 03:24 -0500, Kristoff Bonne <kristoff@...>, wrote:
Serge,


On 3/06/2020 19:31, Sergei Podstrigailo wrote:
KB> I can't speak for John, but I think the question was about a port
of the
KB> complete stack (encoder and decoder) to linux single-board computer or a
KB> MCU or MCU/FPGA.

We are working on full "Hardware pager" with embedded transceiver, STM32 controller and e-Ink display too...
Versions for small Linux systems probably will be made also, but some later...
I hope that's will not be a 'just install and use'  box. :-(


These kind of devices almost killed the spirit of amateur-radio.
Thankfully the maker/hacker-community came to save us.


73
kristoff - ON1ARF




Re: study material to teach hams on datacommunication

Gary McGehee
 

Kristoff,  try these 2 sites : www.complextoreal.com/tutorials
                                           Signals Intelligence Group on Facebook


Re: study material to teach hams on datacommunication

Kristoff Bonne
 

Hi Richard,


I had a number of discussion on this issue with a people on this.

There actually is a pretty good explanation for this. In essence, it is linked to the fact that the state of technology today has moved to a point where it has greatly exceeded the knowledge you need for your hamradio license.


First,
When I explain amateur-radio and the requirement for the exam to people who are interested in Amateur-radio (e.g. at the FOSDEM conference in Brussels where we have an amateur-radio infobooth), I usually compare it to a drivers-licence.
The reason the drivers-license exists is that you drive with your car on the public road together with other people, so you need to have some "proven" basic skills to drive your car so you do not crash in other people or hurt yourself.

The same thing applies for the amateur-radio license, except that it applies to the "radio-communication spectrum" instead of the public road, .. and the amateur license (at least the "full" license) also allows you not only to drive a car, but also to build one (i.e. a basic model of a car) yourself.

Second,
If you look at the courses given in the radioclubs and most of the books you find in the bookshops, they have a very clear goal: allow you to get your ham-license. This means the topics of these courses are the same as the topics of the exams: ... the basic model of a car.



Now, what is the problem?

The issue here is that any new modern is now a very far cry from that "basic model car" I mentioned above.
Modern cars are full of electronics, sensors, all kind of microprocessors running very complex applications to hard-Real-time Operating-systems, CAM-bus to connect it all together, an android-based entertainment system, radars, internet-connectivity, etc.


The same applies for radio-technology.
Radios these days are based in DSP and SDR, include embedded microcontrollers, run algorithms on dedicated FPGAs. Radio-amateur devices include arduino's or embedded linux single-board computers, connect to back-end infrastructure on the net. We use software-tools like antenna-simulation software, electronics simulation tools, PCB design tools, math tools, SDR frameworks, etc. etc.

In addition to that, a lot of these technology depends on a level of math that go far beyond what most hams are used to.


So there is a problem!

In essence, the the basic idea for amateur-radio was been like this:

- the "base knowledge" for all ham-operators is what you need to know to pass the exam
- Once you have your license, it is the club and fellow hams in these clubs (presentations, DIY-building projects, contests, fielddays, ... ) that are the way to go from there, learn more on the things your are interested in.


But as technology has advanced so fast and has become so complex (which also resulted in amateur-radio hobby split in tens of subhobbies), that "the radioclub is where you talk to fellow-minded hams"-model does not really work any-more, or -at least- not for the most advanced parts of the hobby.




So, what is the solution? Make the exam more difficult?
I don't know. OK, A technician working on a car needs to know what sensor-board of the car does what and how it connects to the rest of the car, but can you require him/her to explain how the embedded code on the microcontroller on that PCB interfaces with the CAM-bus and handles interrupts of incoming packets over that bus?


The same thing applies for the amateur-radio exam:
Can you require a candidate licensed ham to explain how to write arduino-code to interface an arduino to an FM-transceiver to send out POCSAG paging messages, ... just to get their amateur-radio license?
That is -I think- not what the exam is about. As mentioned. The exam is there to prove you know how to operate a radio, design a basic transmitter so you do not interfere with other radio-users and you do not blow up yourself.
As a consequence, arduino-code and the POCSAG message -format does not belong in the lessons provided by the radio-clubs to get people licensed.


So, ... then what?

Well, as I mentioned, what I think would help is self-learning-track so that people who *are* interested to go "to the next step" are able to do so.

That will help both these individual hams, and also clubs who want to help members to take that step in a "group" context.



73
kristoff - ON1ARF

On 26/06/2020 00:25, Richard in NC via groups.io wrote:
Back in the day when the FCC gave the ham radio tests (in the FCC office) you actually had to learn about electronic theory and there were no published questions or answers. Only a brief overview of what the test would cover. For example, the Novice license covered very little electronics, the General theory (which was the same as the Technician theory as there was element 3 and not a 3a and 3b) you had to learn about FM theory and oscillators, some SSB theory, antenna theory, the Advanced license required more in depth theory and knowledge of troubleshooting, and the Extra required even more knowledge. Once the questions and answers were released to the public, people tend to memorize them and not actually learn the theory, nor care to. I myself enjoyed learning about the theory and made a career using it.

I know some who did this and have learned some things about the theory from experience using it, but it is not the same hobby anymore.

73 Richard


Re: study material to teach hams on datacommunication

Richard in NC
 

Back in the day when the FCC gave the ham radio tests (in the FCC office) you actually had to learn about electronic theory and there were no published questions or answers. Only a brief overview of what the test would cover. For example, the Novice license covered very little electronics, the General theory (which was the same as the Technician theory as there was element 3 and not a 3a and 3b) you had to learn about FM theory and oscillators, some SSB theory, antenna theory, the Advanced license required more in depth theory and knowledge of troubleshooting, and the Extra required even more knowledge. Once the questions and answers were released to the public, people tend to memorize them and not actually learn the theory, nor care to. I myself enjoyed learning about the theory and made a career using it.

I know some who did this and have learned some things about the theory from experience using it, but it is not the same hobby anymore. 

73 Richard 


Re: study material to teach hams on datacommunication

Kristoff Bonne
 

Trip,


To be honest, that is not really my problem.

I think that in almost all clubs, you have about 5 % of the people who are interested in homebrew DIY or develop the hobby: the 'maker' and the 'developer' people of the amateur-radio world.
These people are my audience.
And, to be honest, I don't even know to what degree that is all linked to the exam. Most of the more interesting things digital communication are not in the exams neither, so are not even part of the courses given by the clubs.

I just want to be able to help these one or two people in a club that *do* are interested in really knowing how something works, who *do* want to build stuff themselfs  and who *do* want to be more then just an operator.


My question here is: How do you get these people over the first hurdle: aquiring the required theoretical knowledge without having to know all the math that comes with the "EE-engineering" types of online courses.



73
krstoff

On 24/06/2020 10:31, kt67 wrote:
kristoff,

In the US we are quickly headed for a no test license.
So your fighting an uphill battle.

If you find that book pls let us know, I would read it.

Trip - KT4WO


On 6/23/20, Kristoff Bonne <kristoff@skypro.be> wrote:
Hi all,



As I once wrote some libraries for encoding POCSAG-messages on arduino
and GNU Radio that are now on github, I sometimes get mails from people
asking me about POCSAG.



Now, looking at some of the questions I get, I do notice quite a lack of
basic knowledge on digital communication in the amateur-radio community.
E.g. I do not know how many times I have already explained that FSK
("Frequency Shift Keying") -as used by POCSAG paging-, is in fact
nothing else but a variation on normal FM. I keep on asking myself
"isn't this something that somebody with a ham-license is supposed to
know?"

I get the impression that, although all ham-radio course do explain AM,
FM and SSB, for some reason the "digital" version of them (and how much
they are actually alike) are not really covered; or not to a degree that
people have an idea of digital communication really *is*.
For me, I learned most of digital communication from books (mainly on
land-based digital communication) but I must say that a lot of the books
and study-material on digital communication and datacomm do are either
oriented towards EE students (i.e. with a lot of focus on math) or to
much oriented on "operating" (i.e. not providing a descent theoretical
background on the topic)


So, ..  I'm looking for study-material or books that a provide a base
and descent theoretical background on the topic, but without all the
math that comes with the EE engineering-courses. By preference, the
course would build on the material used of the ham-radio license exam.
My target-audience is a typical amateur-radio operator:  learned
electronics via a courses in a local radio-amateur club, either no or
limited technical background) .

What would you advice to a fellow ham that wants to learn more about
digital communication, going beyond being just an operator?



Does the ARRL sell any good books on this topic?




73
kristoff - ON1ARF






Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

 

On 6/24/2020 12:05 PM, Cliff Fox (KU4GW) wrote:
People already complain about the Automatcally Controlled Digital
Systems like Winlink and nothing has been done about them randomly
transmitting on top of ongoing communications.
Not to defend Winlink, but the so-called "Auto" stations do not transmit
unless queried by a manned station. Which is really more of a semi-auto
with one end being attended and needing to ensure the frequency is clear.

Most of the so called "Automatic" station complaints are really about
the classic hidden terminal case where a station could not hear one end
of a transmission in progress, and thus initiated communication. Happens
a thousand times a day on Voice/CW, so why would we think the digital
modes would automatically have a magic fix?

Don't have a horse in that race, but it is a common misconception.

Have fun,

Alan
KM4BA


Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Chiefsfan2
 

HF (pager) is just a title. If you look at the actual software, it is a app that allows two way texting. It sends a beacon if you you want which is no different than any other beacon in the amateur radio service which would be a one way communication. There are some groups actually using pagers on ham frequencies to alert their ares teams and also just for fun, are these in violation?

On Jun 24, 2020, 11:15 -0500, Cliff Fox (KU4GW) <cliffku4gw@...>, wrote:
I do see possible violations, it's up to the FCC's interpretation of the rules.
 
§97.113   Prohibited transmissions.
(a) No amateur station shall transmit:
 
(5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services.
 
*(The FCC already has frequencies allocated for pager systems)
 
(5)(b) An amateur station shall not engage in any form of broadcasting, nor may an amateur station transmit one-way communications except as specifically provided in these rules; nor shall an amateur station engage in any activity related to program production or news gathering for broadcasting purposes, except that communications directly related to the immediate safety of human life or the protection of property may be provided by amateur stations to broadcasters for dissemination to the public where no other means of communication is reasonably available before or at the time of the event.
 
*(A pager system is a one-way communication.)
 
I guess it would be up to the FCC whether to enforce the rule and given their recent history of Part 97 Rule enforcement, barely any at all, you can certainly give it a try to find out. The worst that would probably happen would likely be only a letter saying you can't do it. If they sent a letter saying that and then it was ignored then it may get worse. Give it a try, but choose your operating frequencies wisely so no one complains to the FCC about it interfering with ongoing communications. People already complain about the Automatcally Controlled Digital Systems like Winlink and nothing has been done about them randomly transmitting on top of ongoing communications. The ARRL's solution is them wanting to take 3600-3650 Khz away from Extra Class operators on 75/80 meters and use it for ACDS stations, but that's currently only a proposal (See ARRL Draft Bandplan Rev3h - 29Jan2020 Page 5 of PDF version) that hasn't been approved yet. I rarely get QRM from ACDS on 75/80 meters, 40 meters is where they're always giving me problems. The ARRL's bandplan proposal sets aside 7100-7125 Khz for ACDS on 40 meters. The same proposal includes giving phone privileges to Technician licensees from 3900-4000 Khz with a 200 watt maximum power limit. I have no problem yielding the bottom 50 khz of my Extra Class privileges to ACDS on 80 meters or the 7100-7125 on 40 meters. I do hope they don't grant the Technician licensees phone privileges on 75 meter phone because of 2 reasons; (1) Have you listened there how bad things have gotten there since they dumbed down the exams and dropped the code requirement altogether? It has gotten much worse from my soon to be quarter century of having my license! I had a station key up and ask me for a SWR report a while back! LOL! and (2) They don't deserve it! They need to get more education on radio in general, how it works, the technical side of things like what heterodyning is, what SWR is, etc. Just this OM's opinion. 
 
Very 73 and good luck!
Cliff, KU4GW


Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Cliff Fox (KU4GW) <cliffku4gw@...>
 

I do see possible violations, it's up to the FCC's interpretation of the rules.
 
§97.113   Prohibited transmissions.
(a) No amateur station shall transmit:
 
(5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services.
 
*(The FCC already has frequencies allocated for pager systems)
 
(5)(b) An amateur station shall not engage in any form of broadcasting, nor may an amateur station transmit one-way communications except as specifically provided in these rules; nor shall an amateur station engage in any activity related to program production or news gathering for broadcasting purposes, except that communications directly related to the immediate safety of human life or the protection of property may be provided by amateur stations to broadcasters for dissemination to the public where no other means of communication is reasonably available before or at the time of the event.
 
*(A pager system is a one-way communication.)
 
I guess it would be up to the FCC whether to enforce the rule and given their recent history of Part 97 Rule enforcement, barely any at all, you can certainly give it a try to find out. The worst that would probably happen would likely be only a letter saying you can't do it. If they sent a letter saying that and then it was ignored then it may get worse. Give it a try, but choose your operating frequencies wisely so no one complains to the FCC about it interfering with ongoing communications. People already complain about the Automatcally Controlled Digital Systems like Winlink and nothing has been done about them randomly transmitting on top of ongoing communications. The ARRL's solution is them wanting to take 3600-3650 Khz away from Extra Class operators on 75/80 meters and use it for ACDS stations, but that's currently only a proposal (See ARRL Draft Bandplan Rev3h - 29Jan2020 Page 5 of PDF version) that hasn't been approved yet. I rarely get QRM from ACDS on 75/80 meters, 40 meters is where they're always giving me problems. The ARRL's bandplan proposal sets aside 7100-7125 Khz for ACDS on 40 meters. The same proposal includes giving phone privileges to Technician licensees from 3900-4000 Khz with a 200 watt maximum power limit. I have no problem yielding the bottom 50 khz of my Extra Class privileges to ACDS on 80 meters or the 7100-7125 on 40 meters. I do hope they don't grant the Technician licensees phone privileges on 75 meter phone because of 2 reasons; (1) Have you listened there how bad things have gotten there since they dumbed down the exams and dropped the code requirement altogether? It has gotten much worse from my soon to be quarter century of having my license! I had a station key up and ask me for a SWR report a while back! LOL! and (2) They don't deserve it! They need to get more education on radio in general, how it works, the technical side of things like what heterodyning is, what SWR is, etc. Just this OM's opinion. 
 
Very 73 and good luck!
Cliff, KU4GW


Re: study material to teach hams on datacommunication

kt67
 

kristoff,

In the US we are quickly headed for a no test license.
So your fighting an uphill battle.

If you find that book pls let us know, I would read it.

Trip - KT4WO

On 6/23/20, Kristoff Bonne <kristoff@skypro.be> wrote:
Hi all,



As I once wrote some libraries for encoding POCSAG-messages on arduino
and GNU Radio that are now on github, I sometimes get mails from people
asking me about POCSAG.



Now, looking at some of the questions I get, I do notice quite a lack of
basic knowledge on digital communication in the amateur-radio community.
E.g. I do not know how many times I have already explained that FSK
("Frequency Shift Keying") -as used by POCSAG paging-, is in fact
nothing else but a variation on normal FM. I keep on asking myself
"isn't this something that somebody with a ham-license is supposed to
know?"

I get the impression that, although all ham-radio course do explain AM,
FM and SSB, for some reason the "digital" version of them (and how much
they are actually alike) are not really covered; or not to a degree that
people have an idea of digital communication really *is*.
For me, I learned most of digital communication from books (mainly on
land-based digital communication) but I must say that a lot of the books
and study-material on digital communication and datacomm do are either
oriented towards EE students (i.e. with a lot of focus on math) or to
much oriented on "operating" (i.e. not providing a descent theoretical
background on the topic)


So, ..  I'm looking for study-material or books that a provide a base
and descent theoretical background on the topic, but without all the
math that comes with the EE engineering-courses. By preference, the
course would build on the material used of the ham-radio license exam.
My target-audience is a typical amateur-radio operator:  learned
electronics via a courses in a local radio-amateur club, either no or
limited technical background) .

What would you advice to a fellow ham that wants to learn more about
digital communication, going beyond being just an operator?



Does the ARRL sell any good books on this topic?




73
kristoff - ON1ARF






study material to teach hams on datacommunication

Kristoff Bonne
 

Hi all,



As I once wrote some libraries for encoding POCSAG-messages on arduino and GNU Radio that are now on github, I sometimes get mails from people asking me about POCSAG.



Now, looking at some of the questions I get, I do notice quite a lack of basic knowledge on digital communication in the amateur-radio community.
E.g. I do not know how many times I have already explained that FSK ("Frequency Shift Keying") -as used by POCSAG paging-, is in fact nothing else but a variation on normal FM. I keep on asking myself "isn't this something that somebody with a ham-license is supposed to know?"

I get the impression that, although all ham-radio course do explain AM, FM and SSB, for some reason the "digital" version of them (and how much they are actually alike) are not really covered; or not to a degree that people have an idea of digital communication really *is*.
For me, I learned most of digital communication from books (mainly on land-based digital communication) but I must say that a lot of the books and study-material on digital communication and datacomm do are either oriented towards EE students (i.e. with a lot of focus on math) or to much oriented on "operating" (i.e. not providing a descent theoretical background on the topic)


So, ..  I'm looking for study-material or books that a provide a base and descent theoretical background on the topic, but without all the math that comes with the EE engineering-courses. By preference, the course would build on the material used of the ham-radio license exam.
My target-audience is a typical amateur-radio operator:  learned electronics via a courses in a local radio-amateur club, either no or limited technical background) .

What would you advice to a fellow ham that wants to learn more about digital communication, going beyond being just an operator?



Does the ARRL sell any good books on this topic?




73
kristoff - ON1ARF


Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Chiefsfan2
 

I don't see any violations.

On Jun 23, 2020, 00:00 -0500, Cliff Fox (KU4GW) <cliffku4gw@...>, wrote:
Unfortunately this may be illegal on amateur radio in the U.S. under FCC Rules & Regulations Part 97.113 (5) and (5) (b). 

73 de Cliff, KU4GW


Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Cliff Fox (KU4GW) <cliffku4gw@...>
 

Unfortunately this may be illegal on amateur radio in the U.S. under FCC Rules & Regulations Part 97.113 (5) and (5) (b). 

73 de Cliff, KU4GW


Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Chiefsfan2
 

Thanks Segei. I purchased the android app and as soon as I get my radio interface I'm going to try and stir up some activity here in the U.S.

On Jun 16, 2020, 08:48 -0500, Sergei Podstrigailo <amx2@...>, wrote:
Hello all,

HF Pager for Windows V2.80 and HF Pager for Android V3.10 were released:

http://dxsoft.com/hfpagerw.zip

HF Pager for Android 3.10 is released.

https://play.google.com/store/apps/details?id=ru.radial.demo.hfpager

https://play.google.com/store/apps/details?id=ru.radial.full.hfpager

http://dxsoft.com/hfpageraen.html


CPU load has been significant reduced.
Channel busy detection algorithm was improved.
Channel sharing algorithm was improved.



--
Best regards,
Sergei mailto:amx2@...

Windows HAM radio software at http://www.dxsoft.com





Re: New digital mode PS-18 (HF pager) from DXsoft and Radial, or we invented APRS again :-)

Sergei Podstrigailo
 

Hello all,

HF Pager for Windows V2.80 and HF Pager for Android V3.10 were released:

http://dxsoft.com/hfpagerw.zip

HF Pager for Android 3.10 is released.

https://play.google.com/store/apps/details?id=ru.radial.demo.hfpager

https://play.google.com/store/apps/details?id=ru.radial.full.hfpager

http://dxsoft.com/hfpageraen.html


CPU load has been significant reduced.
Channel busy detection algorithm was improved.
Channel sharing algorithm was improved.



--
Best regards,
Sergei mailto:amx2@dxsoft.com

Windows HAM radio software at http://www.dxsoft.com


Re: VARA on FM 2M

Graham
 

On Wed, Jun 3, 2020 at 04:43 PM, Oliver K6OLI wrote:
Have fun experimenting

The  badge's   , FM and  HF are  a little  simplistic ,  
 
Vara  FM  is  intolerant of  frequency  displacement ,  having   no  AFC facility 
this  is inherent  in a  FM system , tx and recovered Rx tone's  are  always
identical [ frequency] . hence  AFC was not  provided.
 
But, out of the  box,  , could also  be  conveyed  via   Am or 
perhaps  pilot  carrier SSB  or  AM- vestigial sideband ? , 
 
9600  , Requires a greater bandwith , as provided  for  9600 packet
hence the  need  to  use the  9600  option  of the  Tx/Rx , 
but is still  essentially FM , with  zero off set capability . 
 
 
Vara HF is provided with AFC and is able to detect off sets, but 
Can also  be  used over  FM links , if the  link is very poor  or 
Narrow  bandwidth , 
 
During testing ,  I found  with a  local satation on 6 meters . 
who , had high 'solar panel' wide band noise , switching  from  SSB
to FM  tx/rx mode  provided a higher  maximum  rate , 

Take a  look at the  V-Sat  for  chat , that  has some  novel 
netting  and  measuring  functions  ..  based on the  HF modem 

Not the  inteded deployements ,  but room  for  experimentation -)

73 -Graham
g0nbd 

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