Date   

Re: High Loss% with ThumbDV on DMR

Steve N4IRS
 

One thing we ran into on some hosts was the latency timer on the FTDI serial driver. I want to repeat, on SOME hosts. Take a look as root: cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer it may be set at 16. set it to a 1 and re-test.

73, Steve N4IRS


Re: High Loss% with ThumbDV on DMR

Tom Corcoran
 

Tnx David and all others. Will assess internet parameters. In meantime, I think I will contain my use of ThumbDV for DStar ... appears that I have no issues on that mode ... Tom VE3NY


Re: High Loss% with ThumbDV on DMR

 

Hi All,

I will try to explain. 

What happens when you sent to the DMR master/reflector.

Every 20ms I receive a DMR voice frame of 72 bits from the ThumbDV. I wait until I have 3 frames. Then I add some extra spicy saus for DMR data ( 48 bits ) ( EMB etc ).
So when I miss one frame from the AMBE I will wait for the next. This is not a loss what you see on the other end!
The 3*72 bits voice + data 48 bits = 264 bits / 8 = 33 bytes is send to the master/reflector + extra headers ( depends on network ). When this data ( 33 bytes + header) is not received, it is a loss.
When the 72 bits voice is corrupted the BER will be higher. 

It is not normal to use TCP as a transport for voice. When you have loss it will re-transmit. And retransmitting is latency or jitter. Jitter is really bad for voice!
Normally voice is transported by UDP. UDP is like a postcard. You never know if the card is received. In the DMR/DSTAR data we also send a kind of sequence number so we can count the loss and do something with it like filling up with white noise. 

There are several tools on internet to test the latency, loss etc. A good internet connection from end to end is very important for voice!

---

Greets and 73,
    David PA7LIM


On 25-01-2018 23:24, John D Hays - K7VE wrote:

Tom -- David (PA7LIM), author of BlueDV, participates on this list, so we may hear from him on this topic.

On Thu, Jan 25, 2018 at 2:22 PM, <tcorcoran@...> wrote:
All,

tnx for very constructive advice. I will pursue with s/w author. 

Tom VE3NY 






 
--


John D. Hays
Edmonds, WA
K7VE
 
   
 


Re: High Loss% with ThumbDV on DMR

 

Tom -- David (PA7LIM), author of BlueDV, participates on this list, so we may hear from him on this topic.

On Thu, Jan 25, 2018 at 2:22 PM, <tcorcoran@...> wrote:
All,

tnx for very constructive advice. I will pursue with s/w author. 

Tom VE3NY 




--


John D. Hays
Edmonds, WA
K7VE

   


Re: High Loss% with ThumbDV on DMR

Tom Corcoran
 

All,

tnx for very constructive advice. I will pursue with s/w author. 

Tom VE3NY 


Re: High Loss% with ThumbDV on DMR

Tom Corcoran
 

Brian,

not sure. Will check. 


Re: High Loss% with ThumbDV on DMR

Tom McDermott
 

Hi Tom,

In my opinion this is not a hardware issue.  The general problem is that the Internet has
variable latency and variable packet loss.  The software feeding a vocoder has to deal
with it.  The use of TCP to recover from lost packets causes a delay in the received
AMBE frames. 

What to do?   

Brute force would be to just throttle the packets to the DV.  But then the latency would
grow with time, and become unusable.  Another approach is for the software to try
to figure out when arriving internet packets are too late and throw them away.

Real time media devices sometimes use a special protocol such as RTP / RTCP to
balance the tradeoff between loss rate and latency.

If the internet path from the source to the destination (involving a lot of connections,
routers, etc.) has loss and / or latency problems, that sort of has to be fixed first.

-- Tom, N5EG





On Thu, Jan 25, 2018 at 1:39 PM, <tcorcoran@...> wrote:
Tnx Tom,

this is is a thorough diagnosis and resolution of the problem. Is this something that should be fed back to NW? Or is DMR beyond the design spec of the ThumbDV? 

I understand conceptually what you have done but would be unable to build the interface to provide packet limiting on my own. Any "brite force" method of limiting packets? Is this something that the vendor could/should provide? I’m using BlueDV but not implying he should do anything. It’s a NW issue - correct?

Tom VE3NY 
_._,_._,_



Re: High Loss% with ThumbDV on DMR

 

The software, in this case BlueDV, controls the packet flow to/from the ThumbDV.   NW Digital Radio is responsible for the manufacture of the ThumbDV and that it performs according to the hardware specs and documentation.  Software is responsible for transport of Audio (PCM) and AMBE to and from the ThumbDV hardware.



On Thu, Jan 25, 2018 at 1:39 PM, <tcorcoran@...> wrote:
Tnx Tom,

this is is a thorough diagnosis and resolution of the problem. Is this something that should be fed back to NW? Or is DMR beyond the design spec of the ThumbDV? 

I understand conceptually what you have done but would be unable to build the interface to provide packet limiting on my own. Any "brite force" method of limiting packets? Is this something that the vendor could/should provide? I’m using BlueDV but not implying he should do anything. It’s a NW issue - correct?

Tom VE3NY 



--


John D. Hays
Director

  


Re: High Loss% with ThumbDV on DMR

 

Is HW flow control enabled? It is a requirement for the AMBE3000 Chip

Bryan K7UDR


Re: High Loss% with ThumbDV on DMR

Tom Corcoran
 

Tnx Tom,

this is is a thorough diagnosis and resolution of the problem. Is this something that should be fed back to NW? Or is DMR beyond the design spec of the ThumbDV? 

I understand conceptually what you have done but would be unable to build the interface to provide packet limiting on my own. Any "brite force" method of limiting packets? Is this something that the vendor could/should provide? I’m using BlueDV but not implying he should do anything. It’s a NW issue - correct?

Tom VE3NY 


Re: High Loss% with ThumbDV on DMR

Tom McDermott
 

Hi Tom,

I've written an interface for ThumbDV to gnuradio.   It runs in DSTAR or DMR
AMBE encoding/decoding mode without losses.  Right now I don't have any modules
written to insert or extract DSTAR bits from a raw 4800 BPS stream, nor
to/from DMR.  So testing is just loop-back:   audio-input to AMBE encoded samples,
those samples looped back to the decoder to audio output.

In writing the gnuradio driver, I ran across one case where the losses were high. For
me this occurred when over-running the ThumbDV with packets faster than a 20 milliseconds
per packet rate.  It was not enough to limit the packets-to-ThumbDV to the 460,800 bps
serial rate,  The device would lose synchronization at the packet level, and eventually
recover after throwing away enough corrupted response packets. Then after a few good
packets it would get lost again.

The device latency appears to be about 3 packets, so it is necessary to pipeline the packets.
It ended up being necessary to limit how many packets are inside the ThumbDV.
My driver limits the number of packets inside the device to 5, it seems to run OK with that.


-- Tom, N5EG









On Thu, Jan 25, 2018 at 10:34 AM, <tcorcoran@...> wrote:
Mike .. good suggestion and tried it ... no luck. still hi loss % 0% BER and Loss figures are all over the map from 0% to 80%. I have tested on DMR/BM and DMR+ with same result. D-Star works fine and "some" TG's are ok. Have also tried other pc's ... same result.

Do either of you or John (or others) have a ThumbDV and, if so, are you experiencing this issue? 

Tom VE3NY



Re: High Loss% with ThumbDV on DMR

Tom Corcoran
 

Mike .. good suggestion and tried it ... no luck. still hi loss % 0% BER and Loss figures are all over the map from 0% to 80%. I have tested on DMR/BM and DMR+ with same result. D-Star works fine and "some" TG's are ok. Have also tried other pc's ... same result.

Do either of you or John (or others) have a ThumbDV and, if so, are you experiencing this issue? 

Tom VE3NY


Re: High Loss% with ThumbDV on DMR

VE3MIC
 

Sounds a lot like streaming issues when connected to the Internet over a marginal wireless access point or low bandwidth connection. If you're using public WiFi when experiencing this, there's not much you can do.  But if you have unlimited data, try creating a WiFi hotspot with your smartphone.


Re: High Loss% with ThumbDV on DMR

Tom Corcoran
 


Thanks for suggestions ....

I will try John's suggestions on sending a ping from my pc to a selected reflector.

Michael, I have tried both plugging into the pc directly as well as using a powered USB port. Same result.

Tom VE3NY 


Re: High Loss% with ThumbDV on DMR

Michael E. Jaggers
 

Plugged directly into the PC or into an external hub?

You may not have enough current capacity to effectively power the ThumbDV.

Try it plugged directly to the PC.

Mike, WB4TTZ

From: John D Hays - K7VE
Sent: Jan 24, 2018 1:40 PM
To: ambe@nw-digital-radio.groups.io
Subject: Re: [ambe] High Loss% with ThumbDV on DMR

Which software are you using with the ThumbDV?

The ThumbDV only deals with serial communications over the USB port.  It is extremely unlikely that any bit errors could be introduced at the USB interface between the computer and ThumbDV.

Bit errors tend to happen in the transport layer, eg. over the air on a weak or interference prone signal, in the modem (which would tend to be a radio), or most likely what you are seeing is UDP packet loss -- if you are seeing packet loss -- I think most dashboards are expressing loss in terms of percentage of packet loss rather than BER.

You may want to run ping between your computer with the ThumbDV and the reflector's IP address (You can find them at https://ar-dns.net) and see what the packet loss is when you kill or stop the ping.  For Windows https://datapath.io/resources/blog/how-to-test-for-packet-loss-on-windows/, on Linux or MacOS, just use the command line ping and run it for a while and then hit Control-C and look at the stats.

On Wed, Jan 24, 2018 at 11:07 AM, <tcorcoran@...> wrote:
Have been using DMR/DStar for couple of years now but I recently acquired a ThumbDV for travel and am generally pleased. However, when I check reflector dashboards, I note high Loss % (yet 0% BER) when on DMR. The loss % is quite volatile as well (5 - 50%). Other stations registering 0% Loss and 0% BER. Anyone else have this experience?

Tom VE3NY




Re: High Loss% with ThumbDV on DMR

 

Which software are you using with the ThumbDV?

The ThumbDV only deals with serial communications over the USB port.  It is extremely unlikely that any bit errors could be introduced at the USB interface between the computer and ThumbDV.

Bit errors tend to happen in the transport layer, eg. over the air on a weak or interference prone signal, in the modem (which would tend to be a radio), or most likely what you are seeing is UDP packet loss -- if you are seeing packet loss -- I think most dashboards are expressing loss in terms of percentage of packet loss rather than BER.

You may want to run ping between your computer with the ThumbDV and the reflector's IP address (You can find them at https://ar-dns.net) and see what the packet loss is when you kill or stop the ping.  For Windows https://datapath.io/resources/blog/how-to-test-for-packet-loss-on-windows/, on Linux or MacOS, just use the command line ping and run it for a while and then hit Control-C and look at the stats.

On Wed, Jan 24, 2018 at 11:07 AM, <tcorcoran@...> wrote:
Have been using DMR/DStar for couple of years now but I recently acquired a ThumbDV for travel and am generally pleased. However, when I check reflector dashboards, I note high Loss % (yet 0% BER) when on DMR. The loss % is quite volatile as well (5 - 50%). Other stations registering 0% Loss and 0% BER. Anyone else have this experience?

Tom VE3NY
_._,_._,_

--


John D. Hays
Edmonds, WA
K7VE

   


High Loss% with ThumbDV on DMR

Tom Corcoran
 

Have been using DMR/DStar for couple of years now but I recently acquired a ThumbDV for travel and am generally pleased. However, when I check reflector dashboards, I note high Loss % (yet 0% BER) when on DMR. The loss % is quite volatile as well (5 - 50%). Other stations registering 0% Loss and 0% BER. Anyone else have this experience?

Tom VE3NY


XC-3006 Redux

 
Edited

XC-3006 Redux

 

We were hopeful to have the Kickstarter produce enough response to deliver the XC-3006 at a bit of a discount to enable delivery at a favorable price point.  Our target was 50 units, or the equivalent in support pledges, but we fell short.

 

However, we were encouraged by the 29 individual pledges that wanted to obtain the XC-3006 and have had some folks ask if there is another way to get the production done.

We have had the house elves running over the numbers and we can do a run if we get at least 25 firm, pre-paid orders, by February 15th.  If you place a firm, pre-paid order, and we do not meet the minimum of 25 orders, we will refund your order.

If this minimum order quantity is met by the February 15th, then we anticipate shipment by mid-April -- baring any unforeseen delays.

When doing a shorter run the cost of parts and manufacturing go up. For example our cost for assembly through the contract assembly house goes up an additional 61% alone. 

Luc informs us that the 2 prototype boards took 8 hours to build using hand assembly, our assembly house has a full SMD assembly and test facility.

 

Here is the offer

 

We have added the XC-3006 for purchase through http://nwdigitalradio.com/product/xc-3006/ at $480/unit plus shipping and sales tax (Tax is collected for orders delivered in Washington State only).


Everyone who pledged at the  $360 or $400 levels via the Kickstarter should have received a discount coupon via email  -- it doesn't match the Kickstarter pledge price, but does bring the price down in consideration of their early support.  

If you signed up for the Kickstarter at the $360 or $400 level and have not received a coupon, contact sales@...

No additional coupons will be issued, however if you wish to buy a quantity of 5 or more units, contact sales for quantity pricing.


After the first batch, we will consider future runs, again as pre-paid, firm, orders within a set timeframe, if there is sufficient interest.

NW Digital Radio is manufacturing the hardware and will support that hardware under our warranty.  Software and configuration support will come from the XLX group and other software developers.

 
--


John D. Hays
NW Digital Radio
K7VE
 
   
 


Re: ThumbDV on Linux

Dylan KI7SBI
 

Thanks John, the usb port power solved my only issue as well.
In my case, the (10 yr old) machine had a 2nd set of usb ports that delivered adequate power.

So that Google will index the error messages, and other users might find the same solution:

 
 
~/DV3000$ sudo ./AMBEserver -s 460800 -i /dev/ttyUSB0 -x
AMBEserver: Starting...
Baud 460800
opened /dev/ttyUSB0 460800
AMBEserver: Opened serial port /dev/ttyUSB0 at 460800 bps.
AMBEserver: Couldn't find start byte in serial data
AMBEserver: error receiving response to reset
AMBEserver: Could not initialize the DV3K!
 
~/Analog_Bridge/DV3000$ sudo python AMBEtest3.py -s /dev/ttyUSB0 -n 
Setting ...
/dev/ttyUSB0
d
8
N
1
False
False
False
 
Reset
6100010033
Wrote: 5 bytes
 
Product ID
6100010030
Wrote: 5 bytes
 
Version
6100010031
Wrote: 5 bytes
 
Set DSTAR Mode
61000c000a013007634000000000000048
Wrote: 17 bytes
 
~/Analog_Bridge/DV3000$ sudo python AMBEtest4.py -s /dev/ttyUSB0 -n -v
Setting serial port
Serial port parameters:
Port name: /dev/ttyUSB0
Baudrate: 460800
Byte size: 8
Parity: N
Stop bits: 1
Xon Xoff: False
RTS/CTS: False
DST/DTR: False
*********************
Testing Reset DV3000
Error, AMBE header was corrupt
Error, no reply from DV3000.  Command issued was: Reset DV3000
Testing Get Product ID
Error, AMBE header was corrupt
Error, no reply from DV3000.  Command issued was: Get Product ID
Testing Get Version
Error, AMBE header was corrupt
Error, no reply from DV3000.  Command issued was: Get Version
Testing Set DSTAR Mode
Error, AMBE header was corrupt
Error, no reply from DV3000.  Command issued was: Set DSTAR Mode
Testing Reset DV3000
Error, AMBE header was corrupt
Error, no reply from DV3000.  Command issued was: Reset DV3000
Testing Set DMR Mode
Error, AMBE header was corrupt
Error, no reply from DV3000.  Command issued was: Set DMR Mode
Testing Decode AMBE
Error, AMBE header was corrupt



<< move DV3000u to a usb port with sufficient power, problem solved >>
 
~/DV3000$ sudo ./AMBEserver -s 460800 -i /dev/ttyUSB0 -x
AMBEserver: Starting...
Baud 460800
opened /dev/ttyUSB0 460800
AMBEserver: Opened serial port /dev/ttyUSB0 at 460800 bps.
AMBEserver: Initialized AMBE3000R version V120.E100.XXXX.C106.G514.R009.B0010411.C0020208.
opened the UDP socket on port 2460
AMBEserver: Listening for connections on UDP port 2460.
 


Re: XCode-3006 usage for end users

Jeremiah Toth (Jay)
 

Ever wanted to run different ham digital applications at once, but had to pick and choose what audio stream/modes you were currently using, because you already had your current single channel device in use?

Once this device is released and AMBE server is updated (which, I think I saw something saying it already WAS updated) then you can monitor multiple modes or reflectors at once.  I plan (if it gets fully funded, fingers crossed) to do experimental work with AllstarLink and MMDVM, as well as perhaps have some DSTAR and DMR going at the same time.  I'm nothing but full of ideas of things to do, since this would allow me to do SIX different things at once without approximately $750 in multiple usb sticks connected to my computer...

KG4VGC

On Thu, Jan 11, 2018 at 5:33 PM, Jeff Marden via Groups.Io <jmardensdl@...> wrote:
Hello John:

So, not really for end users yet; waiting for applicable software to be developed probably after the reflector phase of the overall development - understood.

Thanks,
--
Jeff Marden/N1JCM