World Wide Digi DX Contest
World Wide Digi DX Contest
This latest release has some handy features:
You can download WSJT Improved 2.7.0RC2 at https://sourceforge.net/projects/wsjt-x-improved/postdownload
(TNX W1UE)
With WSJT-X 2.2.2, there is now an explicit configuration choice for the WW Digi Contest. It is on the Settings/Advanced/Special operating activity window: WW Digi Contest. Select this option so that Grid Square only is the sent and expected receive exchange. This also enables the proper format Cabrillo log file creation after the contest for log submittal.
Other software that has an explicit configuration option for WW Digi includes MSHV and DigiRite.
FT decoding depends upon precise start times of each cycle. It is imperative that your PC clock be accurately synchronized to atomic time. The operating system usually does synchronize via Internet time servers, but sometimes it is not consistently accurate enough for reliable FT communication. Windows 10, for example, only syncronizes once a week and sometimes does not connect to the time server. The DT column in WSJT-X shows the time difference in seconds between your computer clock and each decoded station. It is common to see large deltas, sometimes exceeding a second or more.
There are a number of small applications that provide frequent synchronization of your computer's clock:
- Meinberg NTP (K1JT recommends)
- Dimension 4 (K1JT recommends)
- NetTime (W0YK recommends)
- Atomic Clock Sync
Install one of these, or another one of your choice, so that your computer time is close to atomic time and more likely to have a small DT with the stations you work.
A feature of the FT modes is that you simultaneously receive 30-60 stations in your receiver passband. Accordingly, there is no need to work simplex. Each station can find a clear audio frequency and lock their transmit frequency there. Since they can simultaneously copy all the other stations in their pass band, split frequency QSOs can be the default with simplex QSOs being relatively rare. The benefit of stations locking their transmit frequency is reduced pile-up QRM.
It is good practice to find a clear audio frequency and lock it in your software. In WSJT-X this is the 'Hold Tx Freq' checkbox on the main window. Split frequency operation should be the norm in FT contesting.
If you cannot find a clear frequency, then move your radio dial frequency up 2 kHz and see if there are more clear frequencies to select.
The WW Digi rules recommend up to five 2 kHz sub-bands on each band, 80m through 10m, within which to operate. In the 2019 WW Digi contest, stations seldom ventured outside the lower 2-3 kHz. At times, it was so crowded that it was hard to find a clear frequency on which to place your transmit frequency. In addition, the resultant QRM made it difficult to complete QSOs. The solution is to "spread out" into the additional 2 kHz sub-bands where there is less crowding and QRM.
In digital waterfall modes like FT4 and FT8, spreading out must account for the fact that QSO partners may not have identical passbands. For example, one station's passband may be 14090-14092.8 while the other's may be 14090-14094. The latter station can copy the former, no matter where he is transmitting. But, if the latter station transmits between 14092.8 and 14094, that is above the first station's passband and will not be copied.
Since we don't know the passband of other stations and where it is located relative to ours, the recommendation is to place your transmit frequency within the 2 khz sub-band where your QSO partner is transmitting. Even if your passband is 4.8 kHz with a dial frequency of 14090, place your transmit frequency within 14090-14092 if that is where your target QSO partner is transmiting, or 14092-14094 or 14094-14094.8 if your QSO parter is in one of the two latter sub-bands.
Thus, if everyone follows this protocol, they will insure both QSO partners are within each other's passband with the possibility of being copied. The 2 kHz sub-band increments were selected to accommodate the variety of passbands across participants' radios as well as making it easy to remember setting one's dial frequency to an even kHz.
Deep Decode provides slightly better weak signal decoding capability compared to the Fast setting. However, Deep Decode may not be feasible on older, slower computers -- especially in contest situations where the band may be filled with signals. Most modern multi-core PCs can handle Deep Decode, but if you experience decoding issues such as late decodes coming in after cycle end, then you may want to try Fast or Normal Decode.
One can choose to transmit on Even Cycles (00 or 30 seconds for FT8) or Odd Cycles (15 or 45 seconds for FT8). Obviously, you cannot receive when you are transmitting, so obstensively half the available stations to work are not being copied. Therefore it is beneficial to switch cycles periodically to be sure you are accessing all avaiable stations on a band. Just like stations hop between bands and even frequencies within a band in order to find new stations and multipliers to work, the same is the case for alternating between Even and Odd Cycles.
Just like Even and Odd cycles, the choice of operating FT4 or FT8 is part of te strategy of digi contesting. FT4 is intrinsicly twice as fast as FT8. However, it is slightly less sensitive and therefore sometimes less likely to yield a successful QSO. It doesn't take many repeat FT4 messages or, worse, missed FT4 messages before that speed is consumed and maybe even slower overall than FT8. The other consideration is that you may find new stations and multipliers on one mode vs. the other. FT8 is able to copy weaker signals and may yield more distant, and higher point value, stations than FT4.
SO2R can be accomplished by running two instances of the FT software, e.g., WSJT-X. However, dupe checking and new multiplier identification requires either:
1. Restricting each band to just one instance, or
2. Using integrating software such as N1MM+ or WriteLog.
The same mode, either FT4 or FT8, must be run on each instance, otherwise there will be simultaneous transmission for half of the FT4 cycles. This violates the contest rule of only having one signal at a time.
The WW Digi contest exchange only requires the Grid Square whereas the default daily exchange also includes the dB signal report. These two different message sets will interoperate with automatic message sequencing, allowing QSOs with non-contesters. However, the contester may not receive the contest-required Grid Square exchange if the non-contester starts with their Tx2 dB SNR message. And, the non-contester will not receive a dB SNR exchange.
These two problems can be addressed as follows. Let your automatic WW Digi message sequencing run except for the following two cases, where you should be prepared to interrupt your automatic message sequence with an alternate message:
1. When you receive a dB SNR message (Tx2 in WSJT-X default message sequence), send an alternate message, e.g., R-05.
2. If the non-contester first calls you with their dB SNR exchange message (Tx2), it is
difficult to elicit their Grid Square with FT messaging. It is probably best to quickly
finish and log the QSO. One way to insure you get a Grid Square is to only call non-contesters
because it will be in their CQ message. Whenever you call CQ, it is possible that a non-contester
will respond with their Tx2 message. It is important to log this non-scored QSO because if the
non-contester happens to submit a log with this QSO, they will receive a NIL penalty.
When you operate outside the WW Digi recommended sub-bands, it may be better to revert to the default non-contest message sequence (or, use the alternate message feature to manually follow that sequence). This will minimize confusion and frustration for the non-contesters and will allow QSOs to proceed smoothly.
NILs are QSOs in your log that are not in the log of your QSO partner, assuming your QSO partner submitted a log. This can happen in several ways. Perhaps the other station forgot to log the QSO or inadvertently deleted it. Most likely, the reason is that they did not think the QSO was completed. They may not have received your final acknowledgement message, e.g., RR73, even though you may have sent it.
NILs are difficult to avoid and most all logs of even moderate size have a few NILs. The typical average NIL rate across a set of CW/SSB/RTTY contest logs is 1-2%. However, in the 2019 WW Digi contest, as well as other FT contests, the average NIL rate was 5%. The WSJT-X development team along with the WW Digi management team examined the issue and published a paper that concludes with a recommendation for minimizing your NIL rate in FT contesting:
1. Learn how to quickly use alternative messages in your FT software (Alternative F1-F6 Bindings in WSJT-X).
This will allow you to dynamically send a different message than what the automatic sequence would be.
2. Log the QSO when you receive RR73, RRR or 73 from your QSO partner.
3. Log the QSO when you send RR73 and watch carefully in next receive cycle what, if anything, the other
station sends. If they resend their exchange, e.g., R CM97, then resend your RR73 message.
This QSO process is consistent with the common practice in CW, SSB and RTTY contesting. The two stations exchange call signs, reports and acknowledgements (one each). Unfortunately, some FT operators like to send a third acknowledgement, e.g., '73', in response to the RR73 message. This practice is supported by the WSJT-X automatic sequencing which doesn't log the QSO, or present the Log QSO window, until the Tx5 '73' message is sent. The automatic sending of Tx5 can be over-ridden by the operator selecting either a CQ message, or calling another station or by disabling transmit.
If your QSO partner expects a Tx5 '73' message in order to consider the QSO complete and to log it, they will likely re-send their Tx4 'RR73' messwage to communicate that they did not receive a Tx5 '73' message from you. That is your cue to send a alternate message, i.e., F5 for the Tx5 '73' message, as insurance that they will log the QSO.
In summary, don't send, or expect, a third acknowledgement (the Tx5 '73' message) and use the repeated message technique for requesting, or recognizing, a fill request.
NIL Penalty: The Rules specify a NIL penalty of the point value of the QSO. This is in addition to the QSO not counting. The net effect is a score reduction of two times the QSO point value from the raw score. This is to encourage both QSO partners to work together to complete the contact so both can log it.
In the 2019 WW Digi contest the NIL penalty was two times QSO points for a net reduction of three times the QSO value from the raw score. This resulted in large score reductions that many partidipants found alarming. The contest committee ultimately decided to remove the penalty so that the net reduction was only the QSO point value.
For 2020, we hope the 2019 experience plus the recommendation above for minimizing NILs will reduce the average NIL rate. Accordingly, we've moved the NIL rate half-way between the two extremes. Note that the CQ WW CW/SSB/RTTY contest rules all have had the two times NIL penalty for many years now (three times QSO point value deducted).
WSJT-X, N1MM+ and WriteLog/DigiRite Tutorials
Q: What are the proper audio settings for the FT mode?
First, set the audio drive level for or minimum ALC for those radios that specify minimal ALC is appropriate for digital audio modes. For example, the Elecraft K3/K3s manual says to set the MIC level for 5-7 bars of ALC as recommended for SSB. But, digital audio mode operators recommend 3 bars of ALC.
Second, select “Fake It” in WSJT-X or equivalent software if your radio has CAT control. This allows the software to dynamically adjust your carrier and audio frequencies such that the audio signal is above 500 Hz where there is no low-pass filtering degradation.
Q: What software supports this contest?
Most major FT software applications support the WW Digi DX Contest: WSJT-X, MSHV, DigiRite. "Support" includes a configuration option that provides the correct messages and sequencing as well as the creation of the Cabrillo format log file for submittal after the contest. In WSJT-X, this is the "WW Digi Contest" option, selectable in "Special operating activity" in the Advanced tab of the File/Setting window.
Some software may not support the shorter message sequence that exchanges Grid Square only. In this case, the operator can disable the automatic message sequencing or override it by manually selecting alternative messages to match the message sequence used for WW Digi.
If the software cannot create a WW Digi Cabrillo format file for submittal to the contest committee after the contest, then an ADIF format log file may be used. The ADIF log can span a greater time period than just the 24 hour contest. An ADIF Converter is available on the website that will convert any ADIF file to the Cabrillo format needed for WW Digi. This converter will not convert QSO data outside the 24-hour contest period, making it easy to input an ADIF file that may contain contacts from before or after the contest.
Q: What messages do I use for this contest?
When operating in the WW Digi recommended frequencies (Rule II.), select "WW Digi Contest" option in "Special operating activity" in the File/Settings menu item In WSJT-X. Other software may have different ways of selecting the contest message set, e.g., MSHV and DigiRite.
When operating outside the WW Digi recommended frequencies, de-select "Special operating activity" and use the standard default everyday messages in WSJT-X (or, the equivalent in other software). This will avoid the message conflict described in the prior question when working casual stations, not specifically in the contest.
Q: What if my QSO partner sends a dB SNR exchange, but not their Grid Square?
The default everyday WSJT-X Tx2 message sequence sends a dB SNR exchange rather than the station’s Grid Square (Tx1) as a way of shortening the QSO time. However, this means the contest station doesn’t get the Grid Square exchange required by the contest rules and therefore no credit for the QSO. The choice is to not respond to Tx2 callers, or to work them in good will, knowing that they will not contribute to your contest score. This conundrum is similar to working dupes. The QSO time doesn’t increase one’s score, but it gets the duping station out of the way for other QSO partners. As explained above, switch to the default daily message sequence when operating outside the recommended WW Digi sub-bands because most of the stations there will be running that message sequence.
Q: If I call a station that just finished a QSO with a ‘RR73’ message, how do I get their Grid Square?
Your QSO partner will send their Grid Square with their confirmation message (Tx3) for your report message (Tx2). The Tx3 message is designed for exactly this situation.
Q: What is multi-streaming?
The term “multi-streaming” refers to conducting QSOs in parallel where one transmission contains QSO information for 2 or more QSO partners. For example, if two stations answer your CQ, multi-streaming would allow one transmission to contain the signal reports back to each of the two stations. This is a natural consequence of the inherent multi-channel characteristic of the FT mode.
Q: How is multi-streaming done?
As of the 2020 WW Digi DX Contest, there is no satisfactory method available for conducting multiple parallel QSOs in a contest environment.
Q: Isn't the WSJT-X Fox and Hound mode "multi-streaming"?
Yes, but only for a single fox working split frequency. Thus, it is not suitable in a contest where there are many foxes. A large DXpedition is the target user of Fox and Hound mode with the "hounds" being all the DXers striving to work the single DX station.
Q: Why can't there be multiple foxes in a contest?
The current implementation of Fox and Hound mode divides the transmit voltage among 2 or more audio frequencies, one for each QSO partner. This creates two problems in a contest.
First, each contest fox would take up ‘n’ times as much bandwidth as a single audio signal for the ‘n’ parallel QSO partners. In rough terms, this would expand the total contest bandwidth required from a few kHz to over 100 kHz, similar to current RTTY contests. In contrast, FT contests to date have used less than 4-6 kHz per amateur band despite high activity.
Second, the on-the-air RF signal is considerably wider than even the multiple audio frequency signal created by the FT software. While the multiple audio frequency waveforms are each narrow and distortion free, the RF transceiver creates IMD products from the multiple audio signals, much like the classic Two-Tone SSB transmitter test. The result is a signal with very wide skirts, similar to a typical RTTY signal.
It doesn’t make sense to degrade the clean, narrow FT signal into a signal as bad or worse than a RTTY signal. Hopefully, in the future, different implementation techniques will be developed to conduct multiple parallel QSOs while maintaining the inherent clean, narrow signal characteristics of the FT mode.