Flex6300 and SCS PTCiiiUSB Pactor Modem

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  • Updated 3 years ago
  • (Edited)

I have a Flex6300 with SmartSDR 1.4 and a new SCS PTC-iiiUSB HF modem.  I use RMS Express and the WinLink2000 SW.

I've successfully installed and configured both the Flex and the PTCiii USB so that it is recognized and initialized by RMS Express. The Flex sees and talks to the PTC modem.  The RMS Express SW Package sees and talks to both the Flex and the modem. 

I can receive (but not decode) and transmit Pactor data as seen on the Flex6300's panadapter.  My RF output is around 20-30 watts with TXDelay of 20ms.  The Flex is configured for USBDigital with Bandwidth of 3K.  I see lots of Pactor activity, but I can NOT connect to any station (after around 20 short transmissions I get the disconnect message).  Tried to connect to many stations (when channel is clear); tried to connect on different bands (according to propagation), changed to USB mode & different bandwidths, but still can NOT connect.  LEDs on the PTC iii seem to indicate that everything is working fine.

Is anyone successfully using this combination?  I'd appreciate any suggestions to make this work.  thanks, Rich, K3VAT 


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rich

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Posted 3 years ago

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Andrew O'Brien

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What happens if you try Winmor in RMS as opposed to PACTOR, are you able to hold WINMOR connections ?  I don't have a PACTOR modem to test things but with a loaner Flex 6500 I was able to get RMS with WINMOR and the early versions of SmartSDR to work well. Andy K3UK
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rich

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Andy, thanks.  My understanding is that the SCS PTC modem does not support Winmor.  If one wants to use Winmor an external sound card device like a SignalLink would be appropriate.  But I'm far from an expert with these topics.  Rich, K3VAT


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Alex - DH2ID, Elmer

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1. PACTOR is a very fast switching mode done with a SCS PACTOR controller which
    has to hook up physically with cables to a TRX. I run a SCS PTCIIPRO and a SCS
    PTCIIex with either an ICOM IC-756PRO or a YAESU FT-897D. SCS modems have
    been used with the older Flex generation:
    http://kc.flexradio.com/KnowledgebaseArticle50422.aspx
    And the new Flex 6700:
    https://community.flexradio.com/flexradio/topics/6700_pactor_modem
    There are some problems with too much delay during RX/TX switching.

2. WinMOR is a soundcard TNC mode which I have used successfully with my
    6500. You need to install the software RMS Express. 
    http://www.winlink.org/RMSExpress
    Start a WinMOR session, set up TNC, radio and audio and it works.




Both PACTOR and WinMOR can be used to connect to the WinLink
system to send email to the net or to connect directly to another
PACTOR or WinMOR user.

Our German emergency ham radio network works with PACTOR, as it
is faster and more reliable. Another mode which looks promising is
Robust Packet. 

I always use PACTOR for WinLink and my trusty FT-897D if I am at sea.
Woudn't dream of exposing my beloved Flex to salt water ;-)

73, Alex DH2ID
(Edited)
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K6OZY, Elmer

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I think Andy's inquiry on Winmor is to make sure that latency isn't the issue.  Winmor is pretty time sensitive but works properly on the Flex 6000 series.   If you can get that working as a first test, then it would prove that your system isn't having response issues.   I think it was more of a diagnostic step.

I recorded a refreshed session of both sending and receiving email via RMS Express.  

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Alex - DH2ID, Elmer

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Thanks for your video, Christopher. I concur in that WinMOR works quite well with
my Flex-6500, but PACTOR with the SCS TNC's needs faster switching
than the FlexRadios provide. Now if you could use the PIN diode switching
for QSK... ;-)
The best TRX I found for PACTOR use is my IC-756PRO.
73, Alex DH2ID
(Edited)
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Andrew O'Brien

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Alex , when you say ' but PACTOR with the SCS TNC's needs faster switching
than the FlexRadios provide" , is that confirmed by Flex or just your observations at this point?  
Andy K3UK
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rich

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K6OZY: thanks for the info and video on  WinMOR.  As Alex stated in his last posting, "... WinMOR works quite well with Flex ... " and this is what I have found in my research too.


DH2ID: thanks Alex for the info.  I like Andy, K3UK have a BIG question about this "faster switching".  Are you inferring that no one is able to run SCS Pactor on a newer Flex Signature Series because "... [the Flex] needs faster switching ..."? 

Both these hardwares (the Flex and the SCS PTC USB Modems) have been "on the market" for a number of years - one wouldn't think that I'm suddenly discovering some new issue.

73, Rich, K3VAT


(Edited)
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Alex - DH2ID, Elmer

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Rich, you can do PACTOR with FlexRadios of course,
as has been demonstrated, although I'm not so sure about AMTOR,
I wonder if this mode, which needs switching approaching that of full QSK,
has been tried with FlexRadios yet. 

I have been working with PACTOR and AMTOR for quite a long time.
I started with RTTY on VHF and UHF shortly after I was first licenced in 1982,
starting with RTTY on two mechanical machines and PACTOR as soon
as it was on the market with PACTOR-I in 1992.

I wanted to do a circumnavigation with my sailing yacht SKUA, and I
had a PACTOR email system via WinLink aboard in 1999. 

During all this time I relied on fast TX/RX switching TRX like the IC-756PRO,
which I use at home or the FT-897D, which I use (maritime) mobile and portable
and also for emergency work.

PACTOR is very sensitive about RX/TX switching delays.

A good page about the PAXCTOR protocol is her:

http://ecjones.org/pactor.html

And Steve N5AC, VP Engineering, writes in 

https://community.flexradio.com/flexradio/topics/6700_pactor_modem

"...The signal path in the radio works like this: receiver data is passed through the FPGA where it is reduced to a bandwidth that serves our needs, in this case 24ksps at a data rate of 1.536Mbps. While we've not measured it, the latency at this point should be about about 2ms, I believe. This goes through DSP filtering, NB, NR, ANF, AGC which adds about 43ms. 

For true digital work we can generally skip the filters as most digital programs will do their own filtering -- for example a PACTOR modem would tell you to skip the filtering because you add latency and if you don't know what you are doing you can add group delay. So this is why we will do a DIGU/DIGL mode without the filtering or with greatly reduced filtering. 

Finally, we have to send it through OS layers to get to the audio codec. In the FLEX-6000 we are currently using PortAudio and Alsa, neither of which we have spent much time optimizing. Finally any additional filters in the codec (equalizer, for example) can add a little more latency -- generally no more than 10ms. So in the radio today, all of the additional latency is being caused by PortAudio and Alsa. PortAudio and Alsa provide an abstraction and driver layer that make dealing with the audio easier and they necessarily employ elastic buffering to achieve gapless audio. Buffers = latency..."

That's it, coudn't say it better, of course!

73, Alex DH2ID
(Edited)
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rich

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TU Alex for the links and commentary and I have looked at N5AC's technical description on delay/latency for the 6700 (that thread is nearly one year old).

What I am kindly asking for are recommended settings on the Flex6300 AND/OR with the SCS PTCiiiUSB so that I can run PACTOR at least level II and preferably at level III.  There seems to be flexibility in changing delays and levels - I would like to hear from someone who has this combination working. 

73,  Rich, K3VAT

(Edited)
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rich

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UPDATE: I made a few tweaks to both the Flex6300 (turning off AGC) and to the Modem (TX delay=45 ms) and managed to connect to one station here in the US on 20M.  However, the connection did not hold so promptly was disconnected.  At least this is some progress!



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Ed.G, Software Engineer

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We did a lot of work with the signal chains in order to be able to use Pactor with the 6000 series although it does require several settings in place. 

1. You MUST be in DIGU or DIGL with a RX and TX Filter bandwidth greater than 2kHz.
2. If you are in DIGU/L  then the TX/RX EQ and the PROC should be bypassed. In case there is a bug where this isn't happening you might try to disable them yourself before you switch into DIGU/L.
3. All DSP (NB, NR ANF) should be turned off. 
4. The audio level of the Pactor Modem must be calibrated so that the MIC Meter is just below 0 dB.
5. In some cases AGC may add 4ms worth of extra latency to the signal so it may be set to OFF for Pactor as long as the output audio is not clipping.

I don't remember the exact delay settings on the Modem but I believe 10 - 20ms should work.
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rich

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Thanks Ed !!  All of my settings correspond with your recommendations, but my Modem delay is currently set at 45ms.  I can experiment in lowering it to find the sweet spot.  Appreciate the quick feedback.  73, Rich K3VAT


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K6OZY, Elmer

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Hi Rich,  Sorry to resurrect such an old thread, but I was wondering if you got this to work.   I'm contemplating purchasing an SCS DR-7400 but want to make sure it works on the 6xxx series.   I see that they sell a cable now for the 6000.  http://www.farallon.us/webstore/index1.html?c7.html