RBN Hole Introduction

Hi Sota Family,

i plan in the next time to start my Sota Activations on CW.

Where can i find a Introduction to set/create an RBN Hole ?

73 Michael

Hi Michael,

You just put the alert on Sotawatch, that is all.
Example below:

SP15OTA on SP/BZ-047
7‑cw,​ 10‑cw,​ 14‑cw

73, Jarek

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Hello, You can also use wildcards if you are going to activate several summits, for example:
Tomorrow I will be in two summits, the alert is EA7/GR-04X for GR-047 & GR-048
73 Jose

The first result from google searching for RBNHOLE
brings the website of it’s creator explaining all the options:

RBNHole | VK3ARR's SOTA Blog

or document from our HB9SOTA friends:


Hi Sota Friends,

now it is clear that i only set an Alert on Sotawatch. OK.

In the past is use /p on my Callsign DC8YZ/P for Activations. Yesterday i did an test on CW on 40m . When i gave DC8YZ many Skimmers spotted me. When i gave DC8YZ/P absolut no skimmer spottet me ?

What ist the failure? I think i gave correct /P ( da di dit da dit dit da da dit )

Is it possible i use only my Callsign without /P ?

The other possibility is is set an manual spot like in ssb.

73 Michael

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The / symbol in Morse is: dash dot dot dash dot

I tried writing this in _. form but the website changes it. Probably thinks it is computer code. :slight_smile:

One feature that is not well-documented is the wildcard format, useful for multi-summit days. I think either X or ? works, for example:


You will then have to tell the chasers early on which summit you are on exactly. Back when my Morse was even worse than it is now, I would program the reference into a memory on my radio to avoid sending mistakes :grin:

Also useful for multi-summit days is to leave a comment that you might be active longer than the default time window of -1/+3 hours. For example, you can comment S+5 to indicate that you will be active up to five hours beyond the specified time. Be sure to use a capital letter S.

Welcome to the fun world of CW activations!


Use a ? for the wildcard character.

For multi summits days when you will not have any internet access, work backwards and make the spotting window longer with S- and S+

i.e. if you are away for 3 days place the alert on the last day and make the window S-72. The way RBNHole works is looks at the alerts placed and the window times if present and works out what it should spot. But as time advances, alerts age and die and THE WINDOW EXTENSIONS DIE TOO!


Tuesday 14 March 2023
MM0FMF 1200 G1M/SI-??? S-3 S+72 please spot ref when you hear me

That window would be active from 0900UTC on 14-03-23 to 1200UTC on 17-03-23. Which looks perfect for a 3 day adventure. The only problem is the alert drops off the pending alerts after 1200UTC 14-03-23 and the forward window extension is lost. You wont be spotted by RBNHole when you expect.

If you did the following alert

Friday 17 March 2023
MM0FMF 1200 G1M/SI-??? S-75 S+8 please spot ref when you hear me

The spotting window is from 0900UTC on 14-03-23 as before. But this alert stays pending in the system on 14-03-23, 15-03-23, 16-03-23 & 17-03-23. Because the alert is pending then the RBNHole uses the window you give and the alert doesn’t expire till your last day of adventure.

If you have internet access then you can place alerts daily and the window is not so much of an issue.


Please can you clarify this? It makes it sound like any S+ won’t work but that clearly isn’t true. What am I missing?

Perhaps the pending alerts are valid for 24 hours and you mean they drop off after 1200UTC 15-03-23.

I can’t remember what Andrew said the time for processing them was after the alert time passes. Could be 12hrs but the principle of big forward windows closing much sooner than you would expect holds true.



Perhaps this is what happened to me yesterday when I got zero RBN pushes, though spots worked on Monday.
If memory serves, I posted this alert: 2000Z, W6/XX-XXX, 12-03-23, S+54.
I was headed to Joshua Tree NP where summits are either /SD or /CD.
12-02-23 was great with three summits and lots of spots. Summit #3 was the next zulu day.
No worries.
14-03-23 around 21Z I started calling CQ from SD-083 and could not buy a spot. I scraped together seven QSOs to qualify, but got only one SOTA chaser response to my CQs.
Curious. Plenty of RBN spots during the activation. (Boy, was it windy up there!)
Next time I’ll try last day with S-XX method you described.

73, David N6AN

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Hello Sota friends,

I’ve got one more question. And it’s only now that I’ve realized that my DC8YZ skimmer is also doing valuable work for Sota (RBN Hole).

I compare the performance of my simmer on Björn’s site every day


The DC8YZ skimmer is one of the world’s best in terms of accuracy and number of spots on a daily basis.

I would be interested in the following, where can I see where the RBN hole has reached through my DC8YZ skimmer?

Or I would like a statistic

For example

12:47z DL3TU/P 10.1186 CW DM/BW-041 Wandbühl 1007 m 10
[RBNHole] at DC8YZ 18 WPM 2

Who can help me?

Greetings Michael

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I think what you’re asking for is how many times has RBNHole used the spot from DC8YZ as primary skimmer? The answer to that is 243 times since August 2020.

Interestingly, I thought that number was high, but that doesn’t even crack the Top 50 and barely scrapes into the Top 100 at position 91.

So, why is this? RBNHole will choose the highest SNR of any skimmer to post - ignoring the other skimmers even if heard by many different ones. It favours skimmers with good antennas, low noise floor and in a position to pick up where SOTA activations are at their most frequent. So your station may hear the activator, but if another station is slightly closer or with a lower noise, the SNR will be higher, and RBNHole will choose that one first.

The top skimmer is KO7SS with 4,245 spots credited to it. 10 of the Top 11 are NA based skimmers - the only EU skimmer in the Top 10 is OE9GHV (2,423 spots).


I can confirm that the /P is part of what is matched, between the alert and your on-air callsign. My practice is to alert as /P and always sign /P when calling cq. That way RBNHOLE does match my RBN spots with my SOTA alerts.

Alternatively, don’t use /P in either place.

But for LOTW I decided to standardise on /P when activating. LOTW requires the callsign in each log to be identical, including the /P suffix. Otherwise it does not confirm the contact.

73 Andrew VK1DA VK2DA


That’s useful to know. Sometimes the spots it shows have quite low SNR values, so, knowing that was the best at the time, expectations can be adjusted… :wink:

If I’m particularly intent on chasing an activator I may set up a hamalert trigger. Sometimes I’ll limit the trigger to skimmers closer to home…

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Hi Andrew,

thanks for the Information it ist clear for me. That is for the RBN Hole important wich Skimmer bring the best SNR.

Where can i find the Information that my skimmer has 243 RBN Hole Spots ?

73 Michael

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That’s top secret, deep-state, super-admin stuff, because it sits on the logs of the main server (if you haven’t worked it out yet, I wrote RBNHole :smiley: )



So can you clarify Andy’s point about alerts expiring? If I set an alert for 1200 S+72 how long will it actually be valid for?

Waves hands vaguely

24 hours. It’s actually an API thing, not RBNHole specifically in that there’s a limit to how much lookback the API will allow.

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