[Fourlanders] Fw: Re: [wsjtgroup] Re: MSK 144 question

Sun Feb 11 17:09:46 EST 2018

Thinking about this and some of our setups makes me wonder about either
characterizing or calibrating our stations.

Wd neef to plan a tine and method to get sn ultrastable frequency standard
snd measure the accuracy of the stations and transverters for our setup.

Not sure we can adjust, but we need to know our freq error so we fan make
adjustments

On Sun, Feb 11, 2018, 4:59 PM John Kludt <johnnykludt at earthlink.net> wrote:

> Guys,
>
> Interesting stuff and new things to learn and work with.  With our older
> rigs, what do we know about frequency accuracy.  Remember "wide open" we
> are looking at a frequency tolerance of 200 Hz.
>
> With the slow modes FT8, JT65, time is key.  With the fast modes like
> MSK144 frequency is key.
>
> Johnny
>
> -----Forwarded Message-----
> From: "Bob McGraw K4TAX RMcGraw at Blomand.net [wsjtgroup]"
> Sent: Feb 10, 2018 9:44 AM
> To: Joe Dzekevich , wsjtgroup at yahoogroups.com
> Subject: Re: [wsjtgroup] Re: MSK 144 question
>
>
>
> Joe makes very good points.   Additionally this clearly confirms that
> improved frequency accuracy is a must for many modes.  While Joe attained
> good accuracy using 20 MHz WWV, one must ask, what about other bands?
> i.e. 160M? or others?  I find the frequency variation will likely not be
> the same for all bands.   Some may be a bit low while others may be a bit
> high.  This has to do with the accuracy of the various oscillators, the
> accuracy of the reference oscillator and the math in the operating system.
>
> Before settling on one value, one should check several bands using several
> time/frequency broadcast and normalize the overall error.    With this, I
> find my K3S, after warm-up and reference oscillator adjustments, to be +/-
> 1 Hz or better, all bands 160M - 6M.  As to 2M, using my DownEast Microwave
> transverter, I must add correction for the TCXO error in that unit.
>
> 73
>
> Bob, K4TAX
>
> On 2/10/2018 6:31 AM, Joe Dzekevich wrote:
>
> As a follow-up to Bob’s note on freq cal mode.....I have two rigs: a 3
> year old TS-590SG and a 13 year old IC-746PRO.  I ran the freq cal test on
> both, and the TS-590SG had warm-up freq drift issues and the IC-746PRO also
> had the drift issues.  So, given that MSK144 needs to have frequency
> accuracy within 200 Hz, I dropped-in TCXO’s into each rig.  A cheap
> TS-590SG TCXO got me within 4 Hz on WWV 20 MHz and I was able to adjust the
> IC-746PRO to within 1 Hz on WWV 20 Mhz.  Both rigs were also now stable as
> a rock.
>
>
>
> But....that does not mean that when you get up to 6M and 2M that you have
> the same frequency accuracy tolerance.  Using a 200 Mhz counter, I could
> see that while things on 6M were very good on both rigs, when the IC-746PRO
> got up to 2M, it was further off frequency than I wanted.  It was within
> the 200 Hz, but barely, meaning that if stations on MSK144 were off in the
> other direction, I would not decode them.  To fix that, in the WSJT-X
> frequency tables, lower part, you can put-in a frequency offset, plus or
> minus, in Hz, for each band.  For 6M I put-in a very slight offset and on
> 2M I put-in a slightly larger offset.  The goal was to get the rigs within
> +/- 25 Hz so I could decode other stations should their offset be in the
> opposite direction as mine and be well within the 200 Hz for deep decoding.
>
>
>
> In short – everything was a success.  Basically with modes like FT8 you
> need very accurate time.  With the fast modes like MSK144 for meteor
> scatter, you need very accurate frequency.
>
>
>
> Joe, K1YOW
>
>
>
>
> ------------------------------
>
> *From:* wsjtgroup at yahoogroups.com [mailto:wsjtgroup at yahoogroups.com
> <wsjtgroup at yahoogroups.com>] *On Behalf Of *Bob McGraw K4TAX
> RMcGraw at Blomand.net [wsjtgroup]
> *Sent:* Friday, February 09, 2018 8:04 PM
> *To:* wsjtgroup at yahoogroups.com
> *Subject:* [wsjtgroup] Re: MSK 144 question
>
>
>
>
>
> Joe made reference to the radio master oscillator accuracy which is where
> the display numbers on the radio originate.
>
> To that end, the latest release of WSJT-X has a nice mode being FreqCal.
> If you have your radio and computer configured for CAT control, selecting
> this mode will step the receiver through various frequency standard
> broadcasts.  Or you can manually select the frequencies of your choice.
>
> The software automatically sets the radio via CAT control to the specific
> frequency, and then inserts a - 1500 Hz offset.   The table will show as
> such as below. The column of values DF is the error in Hz..   From this
> table I presume my radio to be about -0.2 to -0.5 Hz low looking at the DF
> column.
>
>  UTC       Freq Cal Offset  Fmeas      DF    Level   S/N
>
> 00:42:39 2500 1 1500 1499.797 -0.203 -4.6 47.8
>
> 00:42:41 2500 1 1500 1499.700 -0.300 -4.2 45.8
>
> 00:42:43 2500 1 1500 1499.644 -0.356 -6.2 47.9
>
> 00:42:49 2500 1 1500 1499.747 -0.253 -4.8 50.6
>
> 00:42:51 2500 1 1500 1499.661 -0.339 -0.7 45.4
>
> 00:42:54 2500 1 1500 1499.685 -0.315 -2.0 46.7
>
> 00:42:56 2500 1 1500 1499.745 -0.255 -2.0 47.0
>
> 00:42:58 2500 1 1500 1499.775 -0.225 -1.3 46.6
>
> 00:43:04 2500 1 1500 1499.497 -0.503 -3.9 49.2
>
> 00:43:06 2500 1 1500 1499.506 -0.494 -4.4 49.9
>
> 00:43:09 2500 1 1500 1499.551 -0.449 -2.9 48.5
>
> 00:43:11 2500 1 1500 1499.618 -0.382 -2.0 47.2
>
> 00:43:13 2500 1 1500 1499.655 -0.345 -2.6 47.5
>
> 00:43:19 2500 1 1500 1499.744 -0.256 -3.4 48.9
>
>
>
> This has proven to be a good check regarding ones radio.  I've use a high
> precision source to verify the results are quite accurate.  Again this says
> to me the digital readout on your radio may or may not be as accurate as
> you might like to think and believe.    In my case I've adjusted the
> reference oscillator in my radio to produce the least error on all
> frequencies checked between 2.5 MHz,  5.0 MHz, 10 MHz, 15 MHz and 25 MHz
> WWV signals.
>
>
>
> 73
>
> Bob, K4TAX
>
>
>
>
>
>
>
>
>
>
>
> Re: MSK 144 question
> <https://groups.yahoo.com/neo/groups/wsjtgroup/conversations/topics/27882;_ylc=X3oDMTJyNGk4dnBtBF9TAzk3MzU5NzE1BGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BG1zZ0lkAzI3ODgyBHNlYwNkbXNnBHNsawN2bXNnBHN0aW1lAzE1MTgyMTI0NDU->
> *Fri Feb 9, 2018 6:31 am (PST) . Posted by: * *"Joe Dzekevich" jdzekevich
> <joedzekevich at charter.net?subject=Re%3A%20MSK%20144%20question>*
>
>
>
> Yes, the MSK144 Tx freq is 1500. Now, what you are seeing are folks being
> off freq depending on the accuracy of their rig's freq osc. Most folks
> running MSK144 meteor scatter are usually within +/- 25 Hz or so. If you
> set your freq tol to 200 and deep decode, provided your CPU and memory can
> handle that, you should decode folks on 50.260 with the 1500 Hz offset.
>
> Then, add-in other frequencies to your table, like 50.255, 265, whatever.
> That way you can do easy QSY's or call CQ on .260 and QSY to 255 or
> whatever
> if crowded.
>
> Basically, if your F Tol is 200, then you will decode stations that are
> within 200 Hz of the 1500.
>
> Joe, K1YOW
>
>
> __._,_.___
> ------------------------------
> Posted by: Bob McGraw K4TAX <rmcgraw at blomand.net>
> ------------------------------
> Reply via web post
> <https://groups.yahoo.com/neo/groups/wsjtgroup/conversations/messages/27900;_ylc=X3oDMTJxcTE0cGVpBF9TAzk3MzU5NzE0BGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BG1zZ0lkAzI3OTAwBHNlYwNmdHIEc2xrA3JwbHkEc3RpbWUDMTUxODI3Mzg3NQ--?act=reply&messageNum=27900>
> • Reply to sender
> <rmcgraw at blomand.net?subject=Re%3A%20%5Bwsjtgroup%5D%20Re%3A%20MSK%20144%20question>
> • Reply to group
> <wsjtgroup at yahoogroups.com?subject=Re%3A%20%5Bwsjtgroup%5D%20Re%3A%20MSK%20144%20question>
> • Start a New Topic
> <https://groups.yahoo.com/neo/groups/wsjtgroup/conversations/newtopic;_ylc=X3oDMTJldWMxaTVvBF9TAzk3MzU5NzE0BGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BHNlYwNmdHIEc2xrA250cGMEc3RpbWUDMTUxODI3Mzg3NQ-->
> • Messages in this topic
> <https://groups.yahoo.com/neo/groups/wsjtgroup/conversations/topics/27880;_ylc=X3oDMTM2OXBiOG5jBF9TAzk3MzU5NzE0BGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BG1zZ0lkAzI3OTAwBHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTUxODI3Mzg3NQR0cGNJZAMyNzg4MA-->
> (5)
> ------------------------------
> Have you tried the highest rated email app? <https://yho.com/1wwmgg>
> With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email
> app on the market. What are you waiting for? Now you can access all your
> inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email
> again with 1000GB of free cloud storage.
> ------------------------------
> To unsubscribe, send an email to:
> wsjtgroup-unsubscribe at yahoogroups.com
> Visit Your Group
> <https://groups.yahoo.com/neo/groups/wsjtgroup/info;_ylc=X3oDMTJlaTlpOXRzBF9TAzk3MzU5NzE0BGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BHNlYwN2dGwEc2xrA3ZnaHAEc3RpbWUDMTUxODI3Mzg3NQ-->
>
>    - New Members
>    <https://groups.yahoo.com/neo/groups/wsjtgroup/members/all;_ylc=X3oDMTJmcnAyZWVkBF9TAzk3MzU5NzE0BGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BHNlYwN2dGwEc2xrA3ZtYnJzBHN0aW1lAzE1MTgyNzM4NzU->
>    14
>
> [image: Yahoo! Groups]
> <https://groups.yahoo.com/neo;_ylc=X3oDMTJkcW1vcWY2BF9TAzk3NDc2NTkwBGdycElkAzU3NjQyNTQEZ3Jwc3BJZAMxNzA1MDYzMTA4BHNlYwNmdHIEc2xrA2dmcARzdGltZQMxNTE4MjczODc3>
> • Privacy <https://info.yahoo.com/privacy/us/yahoo/groups/details.html> •
> Unsubscribe <wsjtgroup-unsubscribe at yahoogroups.com?subject=Unsubscribe> • Terms
> of Use <https://info.yahoo.com/legal/us/yahoo/utos/terms/>
>
> .
>
> __,_._,___
>
> _______________________________________________
> Fourlanders mailing list
> Fourlanders at contesting.com
> http://lists.contesting.com/mailman/listinfo/fourlanders
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.contesting.com/pipermail/fourlanders/attachments/20180211/baf45dc5/attachment-0001.html>