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Latency 1.4.....Improvement?

Steve N4LQSteve N4LQ Member
edited June 23 in SmartSDR for Windows
I just had a conversation with a "contesting" friend who said he avoids the Flex due to slow "turn-around" time particularly in SSB mode. It causes him to be one syllable behind the other radios in a contest thus loosing points. According to the QST review, the turnaround time is 138 ms for the 6300 and an even slower 140 ms for the 6700. Looking through reviews of other radios I see number like 38 etc. So I was wondering if ver 1.4 made any improvements in that area which we could pass along to others? I'm not a contester so I'm happy but apparently it is at least a perceived problem among contesters. 73  

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Answers

  • George Molnar, KF2TGeorge Molnar, KF2T Member ✭✭✭
    edited February 2019
    The 6000 uses relays to provide better signal quality, which may slow things down a bit. Perhaps up to 0.1 second per transmission. If a contest operator makes 1000 contacts, and transmits three times per contact, 3000 PTT times .1 second delay, or 300 seconds over the event. Five minutes. How is that costing contacts, really? Especially considering that the time from PTT to speech probably doesn't truncate anything from the exchange (what can you say in 0.1 second?) There are several contest ops here, and I believe the consensus is that the abilities the rig provides more than outweigh an imaginary fault. .
  • W7NGAW7NGA Member ✭✭
    edited January 2018

    simply listen to your signal on an external receiver ... you might be surprised.

    73's

    dan  W7NGA

  • K2CMK2CM Member ✭✭
    edited September 2019
    An f 6.7 k, 2kw pep, a 10 element beam will certainly outweigh any small layency issue.
  • Steve N4LQSteve N4LQ Member
    edited February 2017
    According to the "contester"...The time lapse between when the other guy releases his PTT + time your Flex takes to reproduce his transmission in your ears + time to transmit your response is great enough that someone with a faster rig grabs the attention of the other guy first. It's a difference of over 100 milliseconds between the 6000 series and typical other rigs. I'm just quoting others here but I suspect it is a little more than just an "Imaginary fault". 
    I thought maybe that maybe with ver 1.4, moving some of the cpu work to the 6000 might change the turn time?
  • W7NGAW7NGA Member ✭✭
    edited January 2018

    latency - it's enough that you cannot realistically monitor and assess your signal real-time on an external receiver, and I suspect it could be an issue for the consummate contester.

    dan  W7NGA

  • Ken - NM9PKen - NM9P Member ✭✭
    edited June 23
    The last time I looked, there is no interlock on the flex radio than prevents pressing the PTT before the other station's last syllable fades into the noise. A good contester knows his station and makes adjustments accordingly. One can press the PTT a split second before the other station finishes his "QRZ" and be right there on top of everyone else. In fact, I often see stations begin transmitting several seconds before the DX ends his transmission, presumably on order to get the drop on the competition. (I often wonder if they know that the other station cannot hear them until the DX station stops transmitting....) Yes, timing is often more important than raw power, and articulation is often better than compression, but much of that timing is in the footswitch or VOX, or even more..in the operator's mind.
  • Bill RobertsBill Roberts Member ✭✭
    edited July 2018
    Is this contester named Archie Bunker?  Does he come configured with preconscrewed ideas?
  • Steve N4LQSteve N4LQ Member
    edited October 2019
    The Flex-5000 turnaround time = 29ms
    The Flex-6700 turnaround time = 140ms
    Per QST reviews
    We went from one of the fastest to by far the slowest. 

  • Steve N4LQSteve N4LQ Member
    edited September 2015
    Bill that is so funny. I'l just tell those ole contesters they are Archie Bunkers...Yea that will fix'em. Man why didn't I think of that? 
  • Lee - N2LEELee - N2LEE Member
    edited December 2016
    Steve what ever you do don't convince your contester friend to get a flex. Let him think the delay is a problem.

    The last thing we need is another contester than can hear stations that the Flex users can hear. :)
  • Steve N4LQSteve N4LQ Member
    edited February 2017
    Steve
    Thanks for the informative reply and I now understand. So to answer our contesting friends concerns we need to explain to them that excellent filtering is more important than longer delay. 
    I guess a "contest mode" would be a nice marketing tool. :*)
    72
  • K6OZYK6OZY Member
    edited March 2015
    I think a "contest" mode for USB/LSB filters is a great idea.  We can test latency using DIGU/DIGL but the PROC is disabled so it's not a long term solution.
  • Steve-N5ACSteve-N5AC Community Manager admin
    edited July 2018
    If you guys truly feel you are missing contacts due to the latency I want to hear about it.  If not, I would argue that the filtering is more important.  Agreed that DIGU is not a long term solution -- I just wanted to show you an easy way to test the difference.
  • edited March 2015
    Woudn't a contest mode with poor filter skirts be counterproductive ? If there is one situation where you need good filter skirts ... It's in a contest. Surely no contester would give up these fantastic shape factors for a few msec less latency. How many seconds would be lost in a 48 hour contest asking for a repeat of the exchange because a poor filter skirt made copy impossible?
  • edited March 2018
    Steve, Could you give us some data that compares latency to filter skirts? While I'm not the contester that I used to be in my younger days, with the call WB4PDQ, I think this is worth further discussion. On CW a difference of 100 ms is very noticeable at 40 wpm contest speed.
  • Mike va3mwMike va3mw Member ✭✭
    edited February 2018
    I am calling BS on this and he is just looking for an excuse. I have done hundreds of SSB contests both with and without the Flex and there is no difference that would ever make a difference in my score. If he really knew contesting and it was a pile up, it isn't about being first in, but being heard when there are less people calling. I also contest with a remote base with about 100ms latency (and I have been for almost 10 years) and I have never noticed a difference where it would make an impact on my score. It is 100% operator skill and nothing to do with the change over time. va3mw
  • Barry N1EUBarry N1EU Member ✭✭
    edited February 2017
    What's clearly needed here is hard data, not words - what are the rx and tx latency measurements in milliseconds for the range of filter slope and audio connection settings?  I'd for one appreciate seeing that for the 6300 and 6500.

    Barry N1EU
  • Steve-N5ACSteve-N5AC Community Manager admin
    edited March 2018
    We'd have to go plot them, George, which we could do.  I don't have the plots ready today.  I can tell you that with the highest latency and number of taps, the filters are virtual brick walls.  If you compare the filters in CW mode to the finest crystal filters available in other radios, the shape factors we produce are significantly better.  Here's a post where several folks chimed in, did some plots and talked about the filters:

    https://community.flexradio.com/flexradio/topics/cw_filter_shape_factors?topic-reply-list%5Bsettings...

    The same filters used in CW are also used in sideband so the same numbers apply.
  • Michael - N5TGLMichael - N5TGL Member ✭✭
    edited December 2016
    I'm in the camp that the 140ms delay is just an excuse.  It truly is all about timing, understanding how the other operator is operating and jumping in at the right time.  Unless you have a big gun station, being the first to rattle off your call after "QRZ?" is likely to not get you an answer.
  • WA2SQQWA2SQQ Member ✭✭
    edited January 2017
    In the digital photography world people who scrutinize image quality by viewing images at 400%, or quote numbers that just are not "visible" are called "pixel peepers". My take on this is they are complaining about this "spec" and using it as ammunition to support their decision to purchase the brand they have, over a Flex. Most of them probably wish they waited and bought a Flex! My Flex 6500 allows me to enjoy the hobby which is what it should be about.
  • Barry N1EUBarry N1EU Member ✭✭
    edited February 2017
    I would suggest that where this becomes a real issue in serious (i.e., high rate) ssb contesting is when the latency (sum of rx plus tx latency) is equivalent to a single spoken syllable.  In one likely scenario, what happens is that the dx will hear a quicker responder's signal and then your signal come in with that syllable (or character) delay and the dx gets your callsign wrong.  

    Latency is a trade-off with filter slope steepness.  To throw out a number, perhaps a 2:1 minimum filter slope is needed for serious ssb contesting when the least amount of latency is desired (i.e., sacrificing filter slope steepness for less latency). 

    Barry N1EU
  • Steve W6SDMSteve W6SDM Member ✭✭
    edited March 2015
    There are some really detailed high tech explanations here.  Here's my low tech view of the matter.  We're talking syllables and milliseconds here.  As a mediocre contester myself, I don't see how that can possibly impact your score unless you are one of the top three contenders and the winning difference comes down to that last single contact.  My guess is that this guy scores somewhere in the middle of the pack - otherwise he would be developing contest skills that worked around whatever characteristics the radio had.

    This reminds me of the guys who speed the "5nn" up to 65 WPM in a CW response - how much time did they really save and did it make a difference?

    Whatever latency may be characteristic of the Flex is much outweighed by the various advantages that a Flex offers to contesters.  I wouldn't be surprised if they didn't come out with a SDR-assisted category to level the playing field.


  • KY6LA_HowardKY6LA_Howard La Jolla, CA. Paris and Sablet FranceMember ✭✭✭
    edited June 23
    Winning Contests is about Rate. You don't run high rates by running Search and Pounce. You run rate by holding a frequency and letting everyone come to you. When holding a frequency the 100ms latency is not an issue PERIOD I can see where 100 ms might slow u down in S&P But As I said you are not running high rates in S&P. Even then a BIg Station will easily dominate most everyone else who beat you to the 100MS punch. So I can only surmise that the Latency issue is. Not an issue for Big contest winning stations but might be an issue for someone in the middle of the oack.
  • edited June 23
    For clarification, I think the situation that latency becomes important in a contest is when you are doing Search and Pounce, i.e. moving frequency looking for the next station calling "test". In this mode, the other station will respond to the first, readable station that answers his call. I'm sure that being one tenth of a second behind, given equal readability, will cause you to not get the contact. So, now, you either have to find another station or wait to call the same station again. As Howard has said before, everything in a contest is about rate or contacts per hour. Each missed contact slows the rate. Imagine missing 10 such contacts per hour at a 100 contact per hour rate.
  • edited March 2015
    Sorry, Howard, we "doubled". Lol
  • edited March 2015
    BTW when Running a frequency, I often widen my receive slice bandwidth to make sure I don't miss any callers. Katashi Nose, the former KH6IJ, contester of fame, would often copy multiple stations in his head and answer them in rapid fire. I know, because I was one of the callers back in the '70s. Now that's a way to up your rate...but few of us mortal can achieve that.
  • Bill -VA3WTBBill -VA3WTB Member ✭✭✭
    edited February 2018
    Perhaps his mind has to much latency. What do you do about that? Latency problems, I just can't buy it....
  • edited March 2015
    Howard, when using N1MM+ in CW as SOA, I've hit 100 contacts per hour rate in S&P for the first hour on a good band. The trick is to use CW Skimmer to load up the bandmap. Then to get to the next frequency, you just tap Ctrl < or > and it takes you to the next unworked station on the map. You only have to wait long enough for him to finish his call. I'm sure to win you need to Run some too.

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