Date   

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


Re: digital modes on 2m 70cm

KD7JYK DM09
 

"It is a matter of frequency and not power unless we are talking EW for us military types. Front-end designs prevent a lot of EMI/EMC being addressed here."

Imagine if all the military RF was poured into ISDM bands like consumer garbage, and limited to 100mW!

Kurt


Re: digital modes on 2m 70cm

Joseph Yuna
 

It is a matter of frequency and not power unless we are talking EW for us military types.

Front-end designs prevent a lot of EMI/EMC being addressed here.

-----Original Message-----
From: main@digitalradio.groups.io <main@digitalradio.groups.io> On Behalf Of KD7JYK DM09
Sent: Wednesday, October 21, 2020 12:12 AM
To: main@digitalradio.groups.io
Subject: Re: [digital-mode-radio] digital modes on 2m 70cm

"Bouncing signals off of aircraft could that interfere with electronic systems or communications in the aircraft?"

No, for many reasons. But, in short, think of the amount of RF spew in a radio septic tank such as Los Angeles, and that there are no problems... They fly around in a cloud of GigaWatts, from "DC to Daylight", all signals bouncing off of them, all the time, without issue.

Kurt


Re: digital modes on 2m 70cm

Joseph Yuna
 

First, there are other hyper-spectral systems on the market for the blind.

 

Second, the Tomcat (US Navy not USAF) F-14A+ is no more, The “Falcon” F-16N is an USAF fighter, not long-range fighter interceptor.

 

Third, the F-16N systems were not affected by that radar gun. If so, the Program Office and AO supporting the aircraft should be relieved of all and any future duties within the USAF Acquisition Corp.

 

 

 

Regards,

 

Joseph D. Yuna

Joseph D. Yuna

Principal Systems Engineer

 

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From: main@digitalradio.groups.io <main@digitalradio.groups.io> On Behalf Of Bruce
Sent: Wednesday, October 21, 2020 6:18 PM
To: main@digitalradio.groups.io
Subject: Re: [digital-mode-radio] digital modes on 2m 70cm

 

Hi Graham

You brought back a memory of when I was working for the County as a radio tech. I was troubleshooting a pesky problem with a speed radar gun used by the Sheriff. The needle would hang up about half scale instead of falling to zero. Out of desperation I installed a headphone jack in the Doppler Radar audio path. I found the switching power supply was introducing a whine which was seen as a "signal." After I repaired the power supply, I took it on a test run. With the headphones I could hear the Doppler shift as I panned the dish antenna. Pan the signals up a stairway and I could hear the steps. I could tell where walls were. (Note: this could be developed into a useful tool for the blind) If I aimed it at a vehicle that was using a stick shift I could hear the shift points. Hmmm I thought what would it do with Military aircraft landing at a nearby Navy base? We drove to a frontage road that crossed the landing pattern, stopped and waited. Sure enough, a "Tom Cat F16 was landing. There are no "sights" on the gun to aim the marrow beam - but I was able to get a return and the audio tone went thru a screaming 8-10 KHz and the meter pegged hard well above 100 MPH!! I did not stick around for the MP's to show up! I wonder if the F16 IFF alarm went off?!

73 Bruce WA6DNT       

 

On 10/21/2020 1:34 PM, Graham wrote:

Bruce 

Interesting  point on the  military aircraft , popular rumer had/has  it , that one of the  local  police , out on traffic speed  duty , close to a  scottish air base , out of curiosity , pointed his  hand held 'speed gun' at one of the  aircraft coming  into  land , which lit up the  counter measures suite , end of career .. 

Its more to  re-radiation , most of the  aircraft to  day are  composite hulls ,  [one of the reasons for the  11 meter  ww2 radar , was aircraft wing was round 35 feet , so it gave a  good  return  signal]  so the  signals are not as  good as  in the past , polarisation ,  probably Horizontal , I would  expect the  return  signal to  be modified  , dopper plays a part as well , so the  decoder needs  to have a  wide  acceptance 
bandwidth , I think the  doppler shift is up to  x2  if the  target is  advancing ,  first shift  tx> a/c  then a/c >> rx  , at 600 mph , that's  round  +150 Hz on 2 meter's  ?

Ive  found this  write up  by two  spanish  stations  using a  plotting/ prediction software package to  give the  expected  angles / range , google translate makes a  good  job  of converting  to  english , just noticed it was  back in  2014  , when the  decoder was re-worked  during the  eme  testing

http://hamlincs.blogspot.com/2014/04/aircraftscatter-144mhz-con-opera.html?fbclid=IwAR3KXz9kxfm9-ePVvANjWkI4iOAfG0JtbV76Jps3TC4TXv3gQZUbTHYgJ5Y

This was a  scatter  spot , from a French  10 watt  70 cm  beacon, using a  halo round  Ae to  south of france   to paris 704 Kmt , confirmed by 
the  keeper 

19:56 432418 F5ZAS de F1RJ Op05 -19 dB F:2% in JN18AT 1390,6 Hz

>> Foxsix Htj Yes, Aircraft Scatter, big airplane above Clermont Ferrand (matching with AirScout software).

73-Graham
g0nbd

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