Thanks, Iāll see if I can evaluate black-out-to-alert latency for that app as well.
The NOAA subscription service also sends a summary of the X-ray event, as you said after the extent of it is known, giving the magnitude and start/max/end times. This seems to arrive generally some 20 to 30 minutes after the initial alert message I referred to in the OP.
Hereās the summary message for the flare of 18 MAR:
SUMMARY: X-ray Event exceeded M5
Begin Time: 2024 Mar 18 1902 UTC
Maximum Time: 2024 Mar 18 1919 UTC
End Time: 2024 Mar 18 1928 UTC
X-ray Class: M6.7
Location: S12E62
NOAA Scale: R2 - Moderate
Interesting that the ābegin timeā precedes the obvious fading of signals on the waterfall by quite a bit. As I said, itās the threshold time in the alert that seems to correspond with the start of the fade-out, for this event anyway.
For comparison purposes, I installed the SpaceWeatherLive app for Android by āParsec vzwā yesterday and enabled push alerts for X-ray / flare events. (I assumed this was the app you were referring to, Pete. There was another space weather app with fewer downloads and lower ratings.)
A few hours later, there was an X1.1 flare reaching threshold at 9:16 PM my local time (23 MAR 0116 UTC). The newly installed app did indeed push alerts, first for a radio blackout and later for the flare itself. I think the first of the alerts from the app came about five minutes after the SMS/email alerts from NOAA.
Iāll try to note the alert delivery times more definitely for the next flare (before the app retroactively replaces the time the alert appeared with the time of the physical event! [edit: I think actually it was the OS, not the app, that removed the precise alert time at the turn of the calendar day.]).
This flare did not produce any apparent black-out on my waterfall of the 20 m band. Not surprising as it occurred about two hours after my sunset. I suspect most of the signals on that band would have been coming from locations in or near darkness. Had I instead been capturing 15 m or 10 m with the beam turned to the west, I might have seen some indication of a black-out.
4:42 PM local = 20:42 UTC: fading of signals, increase in noise floor first apparent on waterfall.
4:49 PM = 20:49 UTC: received NOAA alert of X-ray flux >= M5 on phone (via email-to-SMS gateway).
4:51 PM = 20:51 UTC: received NOAA alert of same on PC (via IMAP email client).
5:20 PM = 21:20 UTC: received NOAA summary on PC via email.
The contents say the M5 threshold was reached at 20:41 UTC, maximum flux occurred at 20:56 UTC, and the event ended at 21:01 UTC. One can see signals generally starting to come back at about the latter time on the waterfall.
Interestingly, the SpaceWeatherLive app didnāt produce any alert until I opened the app itself with the intention of confirming alerts were enabled for X-ray events (they were). I have since changed the phoneās OS settings to exclude this app from power saving features. Other apps donāt seem to require this measure to alert properly, though. Next flare, Iāll post an update on whether this worked.
Interesting. I know GOES satellites publish Xflux every minute. Currently, my app probes this data every 5 minutes, but I could easily change that to every minute. That would represent a download of 25.7 kB every minute; so about 1.5 MB an hour.
I never realised this data could be that time critical on a difficult mountain top. I will change my code accordingly and let you know when I did.
@W4GO Never believe a programmer; multiply their time estimates by at least a factor 3! In the end, it took me 3 hours to test and debug, but 1 minute Xflux updates work now and I published the new app version.
However, you will need to reload the web page with CtrlShiftR or clear the browser cache on your smartphone to see the updated version of the app. Otherwise, it takes one week for your browser to realise there is an updated version. You will know you have the latest version when you read the line Updated every minute for Xflux; 5 & 30 minutes for other values.
Please, also note that there is a 3 minute lag between the GOES satellite observation and NOAA publishing the Xflux value in JSON format. To be quicker, one would need to decode the proprietary GOES feed. I am not going to do that, but Python code contributions are always welcome. Anyhow, I assume my app is still quicker than any SMS and e-mail alerts. (Please, test.)
Moreover, their are occasionally small gaps in the satellite observations when the Earth or Moon is obscuring the satelliteās view to the Sun. This tend to happen around noon and midnight and especially around the equinoxes.
Thanks Matt. I really like the idea of knowing there is an X Flare before I deploy an antenna at the summitā¦without adding an extra step to setting up. I looked for aa email - SMS gateway on EE - (a UK carrier) and failed - there isnāt one provided . After a bit more faffing around found iOS has a VIP e-mail that allows an e-mail from a VIP ( Very Important Phenomenon?? ). to appear as a message on a locked phone. It works and will allow iOS users to get an alert that is obvious on a locked phone. Might be useful. 73. Paul
Just email. Iām using my mobile providerās free email-to-SMS service, per the OP. YMMV.
accomplished by subscribing with an email address comprised of my phone carrierās email-to-text gateway (in my case as a T-Mobile subscriber: <ten_digit_mobile_number>@tmomail.net).
I never realised this data could be that time critical on a difficult mountain top. I will change my code accordingly and let you know when I did.
I wouldnāt say itās critical, but potentially helpful in some situations. Experienced operators are used to dealing with degraded HF propagation without the benefit of mobile internet service, e.g., be prepared with multiple bands/modes on HF, handheld for VHF. As my waterfall captures show, the term āblack-outā is something of an exaggeration for ordinary flares.
I think an app/page that one has to actively check would be of most use when one already has reason to suspect a propagation event might be occurring. Signals disappear while operating; is it my gear, X-ray event, geomag event, or something else? Check current space weather to find out.
On the other hand, a push alert is useful in situations that are not conducive to interacting with ones phone. For example, youāve just reached the summit and are about to start setting up the HF station. You hear an alert on your phone indicating that an X-ray event is in progress, so you decide to do VHF first, have a snack, etc. to let the black-out run its course.
Iām late posting an update, but this seems to have gotten the alerts working (and I havenāt noticed any effect on my phoneās power usage):
An M5.4 flare occurred on 11 April, reaching maximum flux at 17:06 UTC.
The SpaceWeatherLive app raised an alert for this event correctly ā that is, without me needing to interact with my device to āwake upā the app ā at 17:09 UTC.
The email and SMS-via-email-gateway alerts from NOAA for the same event were received at 17:11 UTC.
The NOAA alert text indicated the flux threshold was reached at 17:05 UTC.
My SDRās slow waterfall capture of the event, below, shows visible signal fade-out beginning at about 17:04 UTC.
(I donāt have an explanation for the distinctive noise signature appearing on the waterfall at about the same time; it doesnāt look like the increase in noise floor that I would expect from a flare, but I havenāt been able to find a local source for it either.)
The SpaceWeatherLive app for android appears to provide timely push alerts of solar flares and the consequential HF āblack-out.ā In order to get the alerts, you may need to delve into your phoneās settings to exclude the app from power-saving measures.
If you want alerts of solar flares by email, or by SMS provided you have access to an email-to-SMS gateway service, you can subscribe to the NOAA service linked up-thread.
Based on my observations so far, the latency between discernible HF fade-out and alert arrival appears to be about five minutes for the app and about six to seven minutes for the NOAA service. This is probably subject to network-related variability.
Reliability of the alerts from NOAA and the SpaceWeatherLive app has been generally good over the last few weeks. Occasionally, alerts from one or the other service arrive late or not at all. Having both has been useful redundancy.
Today, I needed triple redundancy. Luckily I happened to glance at the waterfall about 10 minutes into the black-out. Otherwise I likely would have missed getting the screen grab.
SpaceWeatherLive only raised the alert for the flare when I woke my phone up ā a recurrence of the earlier problem which excluding the app from power saving in the phone settings has mitigated, though not totally resolved.
Worse, the NOAA alert via email-to-SMS gateway arrived about two hours after the flare and the alert destined for my normal email came about four hours late. I wonder if the sheer volume of space weather events recently has exposed scaling deficiencies in NOAAās alert service.
Itād be interesting to hear others observations on the reliability of the alerts from either service.
I now use the noaa alert - but it does seem to arrive after rather than during the event - but as my phone goes ping and it stays o the screen I at leas notice it - even with summit brain. (Only used 2m on the last summitā¦)
Q). What are the thoughts on the progression of Cycle 25? I know that the last couple of weeks excitement has not yet fed into the data. I think it already looks bigger than Cycle 24 - will we go back to the late 50ās with a SSN of over 300 and how will all the space hardware cope?
Sunspot group 3664 is back, and threw out an X 2.9 flare this morning around 0700z. The associated ionisation wiped out the 80 metre Net I usually participate in on Monday mornings. All across the band all I could hear was local QRM, and it seemed the Hack Green SDR was similarly affected.
I was going to take the hound out early, get back and activateTinto as the WX forecast was for a dry day. Well the forecast changed to wet from 11.00 till 2.30 and then I got the flare email.
There was some blue in the sky and it was warmer, about 18C after 14C yesterday. Dog walked and itās pouring down now. And the sky is a bit broken again. I think Iāll get the Gin out and watch reruns of Roger Moore and lovely 1960s ladies (no Botox, no boob jobs, no tattoos) in The Saint now.
Ah, DXHeat churning away nowā¦ SpE must have just kicked in on 6mā¦
73s
