Date   
Re: ADS-B, MultiPSK, and SDRplay RSP

DSP Engr
 

Patrick,

Thank you for fixing the Auto gain operation in version 4.43.

Re: ADS-B, MultiPSK, and SDRplay RSP

Fred Albertson
 

Thanks Patrick and SP Engr,

I have not been up on the RSP/MultiPSK combo recently.  I'll sure check
it out.

Be safe Both,

Fred

Re: ADS-B, MultiPSK, and SDRplay RSP

Patrick Lindecker
 

Hello,

 

>Patrick is already aware of Auto gain not starting, until the Auto Gain button is pressed and set the first time after startup of MultiPSK

This bug has been fixed in the version 4.43 recently issued.

 

>Hi Patrick - If there is a way to set the RF sampling rate and decimation and further optimize the gain on the RSP2, RSPduo, and RSP1A using MultiPSK, please let us know.

No these parameters are fixed. They are the same for RTL/SDR or SDRplay

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de DSP Engr
Envoyé : mardi 14 avril 2020 21:27
À : multipsk@groups.io
Objet : Re: [multipsk] ADS-B, MultiPSK, and SDRplay RSP

 

Hi Fred - Opening the Transceiver Window and toggling the Auto gain control button seems to have the same effect as turning Auto gain off, then stepping through 1 to 9, then setting the Auto gain. Just a little easier to just toggle the button. Patrick is aware of this issue. I did additionally try the exact method you described and it made no apparent difference from simply toggling the Auto gain button. Even with that, I am seeing reduced sensitivity on MultiPSK as compared to the DUMP1090 app from SDRplay. Patrick is already aware of Auto gain not starting, until the Auto Gain button is pressed and set the first time after startup of MultiPSK. This issue appears to be something different, perhaps RF sampling rate or possibly additional gain optimization needed. With Dump1090, I am using 2MHz RF sampling rate, no decimation. Gain is automatic. 

Hi Patrick - If there is a way to set the RF sampling rate and decimation and further optimize the gain on the RSP2, RSPduo, and RSP1A using MultiPSK, please let us know. Thank you.

MultiPSK and Virtual Radar



DUMP1090 and Virtual Radar

Attachments:




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Re: ADS-B, MultiPSK, and SDRplay RSP

DSP Engr
 

Hi Fred - Opening the Transceiver Window and toggling the Auto gain control button seems to have the same effect as turning Auto gain off, then stepping through 1 to 9, then setting the Auto gain. Just a little easier to just toggle the button. Patrick is aware of this issue. I did additionally try the exact method you described and it made no apparent difference from simply toggling the Auto gain button. Even with that, I am seeing reduced sensitivity on MultiPSK as compared to the DUMP1090 app from SDRplay. Patrick is already aware of Auto gain not starting, until the Auto Gain button is pressed and set the first time after startup of MultiPSK. This issue appears to be something different, perhaps RF sampling rate or possibly additional gain optimization needed. With Dump1090, I am using 2MHz RF sampling rate, no decimation. Gain is automatic. 

Hi Patrick - If there is a way to set the RF sampling rate and decimation and further optimize the gain on the RSP2, RSPduo, and RSP1A using MultiPSK, please let us know. Thank you.

MultiPSK and Virtual Radar



DUMP1090 and Virtual Radar

Re: ADS-B, MultiPSK, and SDRplay RSP

Fred Albertson
 

Hi DSP Engr,

I have noticed an in-sensitivity issue with my RPS2-duo and MultiPSK occasionally.

The RSP, as you said, sometimes seems to be way low on gain when using it with
MultiPSK.  I can usually clear the issue by opening the Transceiver window and
stepping the Gain down to 1, then back up to 9 then switching to Auto.  From then
on it seems to  have more sensitivity. 

I had been meaning to address this with Patrick, but never did.

Hope this helps,

Fred

ADS-B, MultiPSK, and SDRplay RSP

DSP Engr
 
Edited

I did a comparison with MultiPSK versus DUMP1090 (from SDRplay) operating the RSP2 using the direct IQ interface (not the audio interface) and sending ADS-B data to Virtual Radar. I am noting that when operating MultiPSk with the RSP2, the receiver appears to be quite a bit less sensitive. I did set the RSP2 to Port B (and verified operation was actually on port B) and used the same Port B input when applying DUMP1090. I also toggled the automatic gain control in MultiPSK to ensure that the gain was being set automatically by MultiPSK. I am thinking perhaps there is a different RF sampling rate applied or perhaps a gain level issue. What is the best way to optimize the RSP2 RF sampling rate and gain when using MultiPSK?

Here are examples about 3 minutes apart (the fastest I can switch between MultiPSK and DUMP1090 on the same setup):

MultiPSK


DUMP1090

Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

DSP Engr
 

Patrick,

Thank you. Have Virtual Radar working well with MultiPSK.

Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

Patrick Lindecker
 

I mean, consult the manual about the ADSB mode (click on the right button of the mouse, with the cursor over the mode button "ADSB" or the “RAW” button as it is the key button for Virtual Radar).

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Patrick Lindecker
Envoyé : lundi 13 avril 2020 10:42
À : multipsk@groups.io
Objet : Re: [multipsk] 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

 

Hello,

 

>output from MultiPSK to Virtual Radar software

Yes, consult the manual:

 

1. About how modes look like


http://f1ult.free.fr/DIGIMODES/MULTIPSK/digimodesF6CTE_en.htm
Look at this address. You have the sound and visual identification of many
modes.

Note: the RS ID permits to identify a mode and the transmission central frequency (see the paper above).
Click on “ID” for RS ID configuration and “RX ID” to set in ON.



2) About the help in Multipsk:

- To bring up the text manual (contextual sensitive one), click on the right
button of the mouse, with the cursor over the mode button "BPSK31", for
example, or any other button. In the example, only the BPSK31 help will be displayed.


- Also use the button hints (wait a fraction of second over a button).

 

3) About frequencies:

Click on the button "QRG" to get all the more or less HF used frequencies.

Click also on “Mode” and “Frequencies used” (for more information about frequencies).

 

4) For about CW, RTTY configuration:

Click on “Mode” for the different options (bandwidth, speed…).

 

73

Patrick

 

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de DSP Engr
Envoyé : lundi 13 avril 2020 04:02
À : multipsk@groups.io
Objet : Re: [multipsk] 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

 

Patrick,

Thank you. Got the RF path switch going via batch file and the map info is very helpful. With a small 6.5cm ground plane antenna on the RSP2 or RSP1A, sitting on my desk I can get a range of about 165mi. With the same antenna on the roof, the range is extended to around 232mi. So ADS-B is working quite well on MultiPSK. Just out of curiosity, is it possible to send the latitude and longitude data output from MultiPSK to Virtual Radar software? Virtual Radar has embedded global maps with zoom feature, pulls up the aircraft information including tail numbers and flight information, and plots the planes on the resizable maps.

 


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Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

Patrick Lindecker
 

Hello,

 

>output from MultiPSK to Virtual Radar software

Yes, consult the manual:

 

1. About how modes look like


http://f1ult.free.fr/DIGIMODES/MULTIPSK/digimodesF6CTE_en.htm
Look at this address. You have the sound and visual identification of many
modes.

Note: the RS ID permits to identify a mode and the transmission central frequency (see the paper above).
Click on “ID” for RS ID configuration and “RX ID” to set in ON.



2) About the help in Multipsk:

- To bring up the text manual (contextual sensitive one), click on the right
button of the mouse, with the cursor over the mode button "BPSK31", for
example, or any other button. In the example, only the BPSK31 help will be displayed.


- Also use the button hints (wait a fraction of second over a button).

 

3) About frequencies:

Click on the button "QRG" to get all the more or less HF used frequencies.

Click also on “Mode” and “Frequencies used” (for more information about frequencies).

 

4) For about CW, RTTY configuration:

Click on “Mode” for the different options (bandwidth, speed…).

 

73

Patrick

 

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de DSP Engr
Envoyé : lundi 13 avril 2020 04:02
À : multipsk@groups.io
Objet : Re: [multipsk] 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

 

Patrick,

Thank you. Got the RF path switch going via batch file and the map info is very helpful. With a small 6.5cm ground plane antenna on the RSP2 or RSP1A, sitting on my desk I can get a range of about 165mi. With the same antenna on the roof, the range is extended to around 232mi. So ADS-B is working quite well on MultiPSK. Just out of curiosity, is it possible to send the latitude and longitude data output from MultiPSK to Virtual Radar software? Virtual Radar has embedded global maps with zoom feature, pulls up the aircraft information including tail numbers and flight information, and plots the planes on the resizable maps.




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Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

DSP Engr
 

Patrick,

Thank you. Got the RF path switch going via batch file and the map info is very helpful. With a small 6.5cm ground plane antenna on the RSP2 or RSP1A, sitting on my desk I can get a range of about 165mi. With the same antenna on the roof, the range is extended to around 232mi. So ADS-B is working quite well on MultiPSK. Just out of curiosity, is it possible to send the latitude and longitude data output from MultiPSK to Virtual Radar software? Virtual Radar has embedded global maps with zoom feature, pulls up the aircraft information including tail numbers and flight information, and plots the planes on the resizable maps.


Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

Patrick Lindecker
 

Hello,

 

>Aircraft speed indicators are in knots (abbreviated "kts"). Yes, there are many aircraft flying daily here though not as many evening an dearly morning flights.

I will add “kts” to all modes for planes (HFDL, VDL2, ADSB, ACARS).

 

>Regarding the map

From the manual:

For about the maps, Multipsk being compatible with UI-VIEW (about GIF pictures and .INF format description files), all the maps and .INF files of the UI-VIEW MAPS folder can be copied to the Multipsk MAPS folder. Then, the user will have only to import the ones he wishes…

The .CLB ou .CLB.TXT files supplied by the WEB application http://www.sailwx.info/maps/shipplotter.phtml are taken into account by Multipsk.

 

 

>How do you use MultiPSK to switch the RF input path between Antenna Port A and Antenna Port B on the SDRplay RSP2

From the manual:

Associated with "rtl_tcp.exe" and "SDRplay", by pushing on the "Options (port/adress)" button, it is opened a box in which it can be changed:

  • the IP adress: the standard local IP address is 127.0.0.1. For a distant server, paste the server WEB IP adress,
  • the port: the TCP/IP port used, by default, is the number 1234, but it can be changed with the spin button, from 1231 to 1250. So several occurrences of Multipsk can be started, each one connected to a server and so to a different receiver. For this, the PC must be very powerful.

By clicking on the "RSP2 bias-tee", the bias-tee (4.7 V / 100 mA max at the ANT-B antenna output) of the SDRplay RSP2 can be set ("On") or reset ("Off"). Note that this option is not stored, by precaution. So, it will be necessary to configure this option at each Multipsk start-up.

About the RSP2 model and beyond:

If the direct interface with Multipsk does not work (with an error message), try this procedure (thanks to Christian and Fred):

1. start "rsp_tcp.exe -E" (from the Multipsk folder), with, for example, the "SDRPlay_RSP2.BAT" batch file in the Multipsk package.
Note that it can be added the parameter "-P0" = PORT A (default) or "-P1" = PORT B or "-P2" = HIz

2. start Multipsk,

3. press on the "SDRplay" button and, possibly, on "+Speaker" to listen to the demodulated sound

4. press on the "RX/TX screen" button

- If the "SDR TCP/IP" button is pushed, the SdR interface (i.e. I/Q signal) is forced .

- The selection of the SDR TCP/IP server (called "MP" in the protocol) is done with a Combo box:

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de DSP Engr
Envoyé : samedi 11 avril 2020 00:56
À : multipsk@groups.io
Objet : Re: [multipsk] 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

 

Hi Patrick,

Aircraft speed indicators are in knots (abbreviated "kts"). Yes, there are many aircraft flying daily here though not as many evening an dearly morning flights. Regarding the map zoom in capability, it would be nice if added at some point as it would make it much easier than creating an 800x600 map of the local area and creating files for the upper left and lower right designation. Created local maps and have planes plotting nicely on those using ADS-B. An ability to apply 1920x1080 resolution and larger size maps would also be helpful at some point an da zoom capability with those would really be nice. Will also check into using the Google Earth maps. Thanks for your efforts on MultiPSK.




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Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

DSP Engr
 

ADS-B is working well on the SDRplay RSP1A and RSP2 using a small 6.5cm 1/4 wave ground plane antenna for 1090MHz sitting on my desk. Getting at least a 160mi (257.5km) range, so good coverage of the local area.

Question for Patrick - How do you use MultiPSK to switch the RF input path between Antenna Port A and Antenna Port B on the SDRplay RSP2? Antenna Port A is what appears to be always connected when using the RSP2 with MultiPSK; however, Antenna Port B has the bias T which is controlled by MultiPSK. 

Receiving ADS-B well without an LNA and just a direct connection to the 1/4 wave ground plane antenna for 1090 MHz.

Re: Request when using Scan within 141A(ALE) mode + Multipsk 4.43 Test version 2 #141a

Andrew O'Brien
 

There is some increased ALE activity now as a group of hams are alpha testing the Hamring ALE software.  It is very nice software for ALE, especially the GUI.

Andy K3UK 

On Sun, Mar 15, 2020 at 9:51 AM mike agner <ka3jjz@...> wrote:
Dennis, if you are interested in non-ham ALE activity, you should check out the Utility DXers Foryum (UDXF) here on groups.io.  I have been cataloging digital activity reported there for over a year, and there are literally hundreds - sometimes going into the thousands - of ALE reports each month.  Of course a better antenna is always helpful but the activity - worldwide - is certainly there.    Mike


--
Andy

Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

DSP Engr
 

Hi Patrick,

Aircraft speed indicators are in knots (abbreviated "kts"). Yes, there are many aircraft flying daily here though not as many evening an dearly morning flights. Regarding the map zoom in capability, it would be nice if added at some point as it would make it much easier than creating an 800x600 map of the local area and creating files for the upper left and lower right designation. Created local maps and have planes plotting nicely on those using ADS-B. An ability to apply 1920x1080 resolution and larger size maps would also be helpful at some point an da zoom capability with those would really be nice. Will also check into using the Google Earth maps. Thanks for your efforts on MultiPSK.

Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

Patrick Lindecker
 

Hello,

 

>D19AAA2610#DFBTRP  192605    34.3561    -93.5905  280  111.3  444      1196  0.01170
This type of message is unknown (for me).

 

>M50AYV579715,D,2346,5,KMSN,N  35.203,W  94.619,380,028,380
>D24AAA1223#DFBD3M307RNO  DFW  N33240W09738421511051P062260028B0009N33224W097358215
These types of message are in general transmitted as type “15”. I will extend the decoding for type “H1” and “30” to decode the positions.

 

>Also, is there a way to have the aircraft tail number (registration number) show up on the local map instead of the I.D.?

No

 

>Is there a way to expand the local map size to full screen (1920x1080)?
No

 

>Also, if there is a way to zoom in on the local map so that I can see the aircraft in a smaller localized area

No

 

For the two last options, it’s better to use GoogleEarth.

 

>if there is a way to indicate the speed in knots.

I thought that knots was reserved for ships, but it seems also used by planes. I will see this week-end, if there are still planes flying (?).

 

73

Patrick

 

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de DSP Engr
Envoyé : mercredi 8 avril 2020 19:00
À : multipsk@groups.io
Objet : [multipsk] 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

 

[Edited Message Follows]

I am new to MultiPSK. Just wanting to know if I missed something in getting aircraft positions plotted on the Local Map in MultiPSK. Receiving VHF ACARS data without issue. Seeing latitude and longitude data coming in with typically 3 different formats. Select the Display RX positions button each time I see latitude and longitude data received. No planes plotted after two full days of receiving data. Using an RSP1A and MultiPSK licensed non-limited use version. Latitude and longitude positions on VHF here are in the 32N 97W range +/- 1 through 4. ACARS message examples with latitude and longitude data:

For the below, the position is: 34.3561N    93.5905W

04/08/20 01:26:16 UTC
Mode: 2   Identifier: N937AN   Ack.: {NAK}
Message type: H1 (Uplink or Downlink - Message to/from terminal)   Block: 9 (Downlink)
Message: D19AAA2610#DFBTRP  192605    34.3561    -93.5905  280  111.3  444      1196  0.01170
    65.00    -94.22  1.012    0.994    0.022    0.013  -30    0  00  00  288  8        1183
   (Message no: D19A  Flight: AA2610)


For the below, the position is: 35.203N    94.619W

04/08/20 05:46:06 UTC
Mode: 2   Identifier: N925FJ   Ack.: {NAK}
Message type: 30
Block: 4 (Downlink)
Message: M50AYV579715,D,2346,5,KMSN,N  35.203,W  94.619,380,028,380

For the below, the position is: 33.240N    97.384W

04/08/20 03:53:29 UTC
Mode: 2   Identifier: N953AN   Ack.: {NAK}
Message type: H1 (Uplink or Downlink - Message to/from terminal)   Block: 8 (Downlink)
Message: D24AAA1223#DFBD3M307RNO  DFW  N33240W09738421511051P062260028B0009N33224W097358215
20984P075272025G0009N33208W09733221520921P087270027G0009N33192W097307
21530857P102271025G0009A2009   (Message no: D24A  Flight: AA1223)

An additional example is attached. Just wondering if I am missing a setting for MultiPSK to plot locations of planes on the Local Map.




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Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

DSP Engr
 
Edited

Have the mapping figured out, so I can effectively zoom in. Just need to know if there is an easy way to show aircraft tail numbers (registration numbers) and if there is a way to indicate the speed in knots.

Re: 129 MHZ to 136 MHz ACARS Plane Plotting on Local Map in USA

DSP Engr
 
Edited

Set up 1/4 wave 1.090 GHz antenna, TQP3M9037 LNA, and RSP2 for ADS-B reception. Found that I can change km/h to mph on the main screen for MultiPSK and it then changes on the local map, but then I am left wondering what the speed settings in the local map are used for. Also, if there is a way to zoom in on the local map so that I can see the aircraft in a smaller localized area, I am interested in knowing. If there is a way to display the tail number (registration number) on the local map, that would be useful to know as well.

Re: #HelpNeeded L-Band setup #HelpNeeded

DSP Engr
 

Hi Kevin,

The post here has a suggested grid parabolic antenna for L-band with linear feed: https://www.sdrplay.com/community/viewtopic.php?f=5&t=3262 . Go through the entire post from end to end as modifications were made over time for improvements to the antenna and there is a source for the GOES decoding software listed at the end, if you are interested in GOES satellite reception from the USA or GK-2A reception from Australia or parts of Asia. The antenna works reasonably well for L-band HRIT and LRIT signals from GOES and similar satellites. The GOES satellites have a linear polarity for the transmitted HRIT signal and skew needs to be taken into account when positioning the antenna. The antenna in the post is a Premiertek ANT-GRID-24DBI. Many have found that Provantage has historically had some of the better pricing on these antennas, but the price has varied considerably over the past couple of years. It is a WiFi antenna designed for the 2.4 GHz range, but people have been modifying them for use in L-Band, due to the comparatively low cost. Since the ANT-GRID-24DBI antenna is designed for a linear feed, it does not consist of a complete circular dish. If you are looking for a reasonably low cost circular dish, you can find 1m size offset parabolic dishes for satellite TV reception that can be adapted fairly inexpensively though you will need to build the L-band feed for it yourself. Not sure what you want to receive with it. I have also used a 1m TV dish with feed for the appropriate band for C-band AERO, L-Band AERO and GOES HRIT. I have also used a home built 4 ft helical and separately a small home built L-band QFH antenna for L-Band AERO. Anyway, if you let me know what signals you optimally want to receive, I may be able to suggest what antennas I or others have found to work well in the USA.

Re: #HelpNeeded L-Band setup #HelpNeeded

Dan Coleman
 

Kevin: Where are you located? I  may be able to help if you are within reasonable driving distance.

Dan W8KMX

 

Sent from Mail for Windows 10

 

From: Kevin Elliott
Sent: Thursday, April 9, 2020 9:28 AM
To: multipsk@groups.io
Subject: Re: [multipsk] #HelpNeeded L-Band setup

 

DSP Eng,

 

Any recommendations on a cheap 1m grid parabolic dish?

 

Kevin

 

> On Apr 8, 2020, at 7:27 PM, DSP Engr <dsp.engr.pe@...> wrote:

>

> Patrick,

>

> GitHub has modules for decoding L-band HRIT signals from 1.6941 GHz GOES 16, GOES 17, and I believe GEO-KOMPSAT-2A that you may be able to integrate into MultiPSK. GitHub OpenSatellite Project: https://github.com/opensatelliteproject . Contact Lucas Teske, if you have any questions regarding the software. Systems can be built using a modified low-cost 1m grid parabolic antenna, Nooelec SAWbird GOES LNA, and an SDR such as an SDRplay RSP-1A, RSP2, or RSPdx. Post here: https://www.sdrplay.com/community/viewtopic.php?f=5&t=3262

>

>

> <Earth Image False Color September 2018.JPG>

>

 

New release of MULTIPSK (4.43) - P25 Phase 1 #multipsk

Patrick Lindecker
 

New release of MULTIPSK (4.43) and Clock (1.11.9)

 

Pour les francophones: la version en français de ce message se trouve sur mon site (http://f6cte.free.fr). Il suffit de cliquer sur le lien "Principales modifications (courriel avertissant de la sortie de la nouvelle version)".


Hello to all Ham and SWL,

 

The new release of MultiPSK (4.43) is on my Web site (http://f6cte.free.fr/index_anglais.htm).
The mirror site is Earl's, N8KBR: https://www.paazig.net/f6cte/MULTIPSK_setup.exe

The MD5 signature of the downloaded MULTIPSK_setup.exe file to, possibly, check (with WinMD5 for example), that the downloading works without error, is equal to:

91a82da992983d78672aea610fb9d055

Multipsk associated to Clock are freeware programs but with functions submitted to a licence (by user key).

 

The main improvement of MULTIPSK 4.43 is the following:

 

Ham P25 Phase 1 decoding (but not the voice)

 

"P25" is the acronym for "APCO Project 25", for two different radio systems: "Phase 1" (used also by Hams) and the most recent "Phase 2" (not used by Hams). Only the "Phase 1" P25 mode is decoded by Multipsk.

It is used in VHF and in UHF. It is a mode for professionals but also used by amateurs (according to a precise organization). For Hams, it is spread in a world net by using, among other means, repeaters and Internet.

 

The amateur P25 communications are the sole object of the Multipsk decoding (professional communications are decoded but ignored). The P25 is considered as a "professional" mode by Multipsk (but the Ham decoding is not limited in time).

 

It is here only considered the data communication which summarizes to identifiers (callsigns).

Note: the voice communication decoding is excluded because it needs an IMBE Codec.

 

For Hams and SWL, the P25 signal can be received:

·                     either from the discriminator output of a classical VHF/UHF FM receiver via a direct connection to the PC sound card. However, the receiver must have a large reception bandwidth due to the high modulation speed,

·                     or with a SdR receiver (FunCube Dongle, RTL SDR,...) and directly demodulated by Multipsk. It is the simplest solution.

 

Here is the WEB address where you can know where all P25 repeaters are located, with their frequencies, for each country: https://www.repeaterbook.com/repeaters/niche/index.php?mode=P-25

 

This mode is in freeware, so without time limitation.

 

See general specifications below.

 

 

Note about translation of Multipsk.exe and Clock .exe:  the 4.42 version of Multipsk has been translated to Spanish by Joachin (EA4ZB), from French.

See: http://f6cte.free.fr/Translation_files.htm.

 

73

Patrick

 

Description of the P25 mode

Baud rate: 4800 (with 2 bits per symbol so 9600 bps)

 

Modulation : each double logic signal (dibit) directly modulates, through a raised cosine filter (to reduce the bandwidth needed), the VHF or UHF frequency in 4FSK (on about +/- 4.5 KHz). So this signal is received in base band after FM demodulation.

It is also used a "CQPSK" modulation, which is demodulated as C4FM.

 

Reception mode: FM

 

Shape of pulse : raised cosine filter

 

Bandwidth : about 9 KHz

 

Detection and synchronization code: yes on 48 bits.

 

Codes: several codes are used (Hamming, BCH, Golay, Reed-Solomon...)

 

Interleaving : no

 

Scrambling: no

 

Transmission

 

Each "superframe" is composed of the following data units: Header / Logical link 1 / Logical link 2 / Logical link 1 / Logical link 2 / Terminator (with or without Link control).

 

Each data unit is composed of a unique frame synchronization word on 48 bits, followed by a network identifier on 64 bits giving among other information the data unit type, and finally a piece of information depending on the data unit. The lenght and the coding of each data unit are different. The main piece of information is, of course, the digitalized voice.

 

The pieces of information that interest Multipsk are the ones contained in the Logical link 1 unit and in the Terminator with Link control unit, because they carry the IDs (Source + Talk Group or Destination + Source).

 

Note: contrary to DMR, this is not a TDMA system as it is managed only one transmission.

 

For about the interface between your PC and your transceiver, see the paper "HOW_TO_DO_DIRECT_DSTAR_BETWEEN_HAMs_Rev_A.pdf" located in the http://f6cte.free.fr/DSTAR.ZIP file, but taking into account only the reception part (no P25 transmission by Multipsk).

 

 




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