The Holy Cluster: Next-Gen Ham Radio DX Spotting Tool

The Holy Cluster is a modern web-based DX cluster for amateur radio operators. It plots live worldwide spots on an interactive map, making DX (long-distance contact) hunting more intuitive than traditional text-based clusters.

I've been using The Holy Cluster for a little while now in conjunction with a VSPE comm port splitter which enables me to have two programs (The Holy Cluster and my N3FJP Log share the same virtual comm port so that they can both independently read and write to  my radio (frequency and mode).  The result?  Fantastic!

Developed by a team of Israeli hams and supported by the Israeli Association of Radio Communication (IARC), additionally it shows active stations as map pins that include callsign, frequency, mode and other details in real time.

Key Features:

Interactive Global Map: A live world map shows incoming DX spots as pins. Each pin reveals the station’s callsign, frequency, mode (SSB, CW, FT8, etc.), timestamp and notes, giving a visual “snapshot” of current activity.

Color-Coded Band Overview: Bands are color-coded on the map and band bar, so you instantly see which HF bands are open and where stations are active. This makes it easy to spot DXpeditions or contest activity at a glance.

Advanced Spot Filtering: Robust filters let you narrow spots by band, mode, continent/country, or even callsign prefix/suffix. You can isolate rare regions or modes, hide self-spots (portable stations), and toggle filters on/off without reconfiguring.

Custom Alerts: Set up alerts for specific DXCC entities or callsigns so you never miss a rare station. The Holy Cluster can notify you when a target appears, ensuring you catch fleeting openings.

Intuitive UI: The site uses a clean, responsive design that works on desktop and mobile. It offers features like dark mode and a “band bar” frequency display for each band. Auto-zoom keeps all spots in view as they appear, and you can sort the spot table by any column for easier reading.

Live Logging/CAT Support: Integration with a lightweight “CAT Server” means you can click a spot to tune your radio (via compatible software). This bridges The Holy Cluster with your transceiver, streamlining your workflow.

Open Source & Community-Driven: The Holy Cluster is fully open-source and free. Its code is on GitHub and developers actively incorporate user feedback into updates. Because it’s maintained by radio amateurs for radio amateurs, new features roll out quickly to meet hams’ needs.

Benefits for Operators:

DXLook.com Launches New Composite Views to Compare Real-World Contacts with Propagation Predictions

DXLook.com has released two new composite map views designed to help amateur radio operators compare actual on-air results with propagation expectations in one place. The update adds Reports + MUF and Reports + VOACAP, allowing operators to see where signals are being reported versus where models suggest they should propagate.

Reports + MUF: This view overlays real contact reports (solid arcs) on top of MUF (Maximum Usable Frequency) zones. The colored zones represent the highest usable band by direction, helping operators quickly confirm whether contacts align with expected openings and identify unusual paths such as grey-line effects, sporadic-E, or long-path propagation.

Reports + VOACAP: This view overlays real contact reports (solid lines) with VOACAP theoretical predictions (dashed, semi-transparent arcs). It provides a direct side-by-side visual comparison between model-based expectations and real-world activity, making it easier to spot agreement, gaps, and surprises.

How to Access: At DXLook.com, operators can try the new views by visiting dxlook.com, selecting Reports + MUF or Reports + VOACAP from the View dropdown, then entering a callsign or grid square and clicking Go.

The MUF/VOACAP prediction backdrop refreshes every 5 minutes independently

Reports refresh based on the selected time window (1 minute to 24 hours)

Existing Reports features remain available, including filters for band/mode/direction, marker options, and the spot table

DXLook.com is free to use, requires no login, and aggregates data from PSK Reporter, Reverse Beacon Network (RBN), WSPRnet, and DX Cluster, supporting bands from 160m through 2m.

About DXLook.com

DXLook.com is a web-based platform that combines reception reports and propagation-focused views to help amateur radio operators monitor activity, understand band conditions, and explore propagation patterns in real time.

70th Anniversary of the 1956 Ground Level Event

It doesn't have a catchy name, and most people have never heard of it. Yet space scientist Clive Dyer of the Surrey Space Centre can't stop worrying about 'GLE05'--a major solar radiation storm in 1956. 

The 70th anniversary of this cosmic event was marked three days ago.  "February 23 is the 70th anniversary of that extreme space weather event," says Dyer. "If it happened again today, it would have a significant impact on air travel and modern technology." 

Above: A drawing of the giant sunspot that caused the Feb. 23, 1956, GLE.

On Feb. 23, 1956, radiation sensors around the world suddenly went haywire as radiation levels spiked to values as much as 50 times normal. No one had ever seen anything like it. "The increase was so dramatic that some observers switched-off their monitors believing them to be malfunctioning," says Dyer. 

The radiation came from "McMath Region 3400"--an enormous sunspot spanning 60° in solar longitude, which flared shortly before the particles arrived. Normally, our atmosphere would harmlessly absorb the radiation, but not this time. Solar particles penetrated all the way to the ground. 

"We call this a Ground Level Enhancement (GLE)," explains Dyer, "This was the biggest of the modern era, and even today nothing has come close to matching it." (A widely publicized GLE last November only amounted to 2% of the 1956 event.)

According to Dyer's calculations, GLE05 would have delivered as much as 10 millisieverts of radiation to passengers on a high-altitude transatlantic flights--comparable to multiple chest CT scans in a few hours. The effect on satellites might have been significant except for one thing: There were no satellites. Sputnik wouldn't be launched until the next year.

How times have changed. in 2026, Earth is surrounded by a swarm of more than 10,000 active satellites with electronics so sensitive that even a single  particle of "hard radiation" can reboot onboard computers or or burn out memory locations.

"Such energetic particle events are nearly impossible to shield," says Dyer. "We need to be prepared--not if but when this happens again."

Interestingly, the last few days have marked a period of zero sunspots on the side of the sun facing Earth, something that hasn't happened for the last several years.

Open HamClock Backend - Another HamClock Server Option

Udo Koch, N0LSR has great support for the Inovato Quadra and is marketing the same hardware as Inovata has stopped its sales due to health issues.  At https://www.n0lsr.com/, Udo discusses the future of Hamclock and gives a rundown of the currently three dominant Hamclock related projects: Classic HamClock, Open HamClock Backend (OHB) which Udo supports, and Open HamClock, a browser-based site (that offers an alternative presentation to the traditional HamClock theme.

Classic HamClock : This project is the product of Bruce Edrich, W4BAE and his team of volunteers.  I've profiled the Classic Hamclock backend extensively in my Feb. 25-26 posts and had been running that backend version for a few days.  The current version is still being tweaked (as are all of the projects) and I like it.  However, RandomWire states "that there are a lot of reports that devices are locking up and will require a full factory reset to come back.  I therefore caution not to use the hamclock.com server solution and rather go with OHB" (see below).

Open HamClock Backend (OHB): OHB is from the efforts of Brian Wilkins, KO4AQF and his team.  Based on Udo's suggestions, I'm now trying that backend and I have to say that I really like the map renderings.  The only issue I've found so far is that the VOACAP window (as opposed to the VOACAP related maps) does not seem to populate for the moment, but this may simply be a current propagation issue.  According to Udo, the OHB server has the advantage of being open sourced and not being centrally based.  OHB pulls data in directly from the sources.  Udo provides detailed OHB changeover instructions at: https://www.n0lsr.com/tipsandtricks.  RandomWire also opines that OHB is the most stable and advanced solution and is ready for prime time.  

Open HamClock (OHC); I've run the third option, Open HamClock for a couple of weeks.  This option is browser based and should not be confused with Open HamClock Backend (OHB).  I like the information it provides, but have issues in trying to customize it to my liking.  It also radically differs from the traditional HamClock theme which I actually prefer.

How to Set Up Your First Flight Simulator At Home

What works and what to skip when it comes to buying your first flight sim

Some students arrive at their first flight lesson surprisingly comfortable in a cockpit. 

They understand the purpose of most instruments and generally know what most of the various knobs and switches do. They already have some rudimentary flows. Their eyes naturally scan the instruments in a familiar rhythm. 

You can tell they’ve spent time in a home simulator.

However, once they take to the air for the first time, it is not hard to distinguish between those who have only flight simulator software and a joystick and those who have a more realistic setup. Some do well while others struggle as they get used to the feel of real controls, refine their rudder coordination skills, and attempt to tune radios and VORs without the option of hitting a “pause” button. 

The difference is not how much time they spent in the sim. It’s what they used, and how they used it.

Home simulators can be excellent tools, but they can reinforce good habits or train bad ones. They can accelerate learning or slow a student down.

With the right hardware, even a modest home setup can provide real value. With the wrong hardware, all you may be building is muscle memory for mistakes. You don’t need to spend a fortune, but not all budget gear is created equal.

Here’s what’s worth your money—and what isn’t:

How to Update the Inovato Quadra to the Classic HamClock Backend

Here's a great video and instructions from Don, W8CPT on updating the Inovato Quadra to the Classic HamClock backend (as discussed in yesterday's (February 25) post).

The written instructions mentioned on hamclock.com, follow Don's video.

 

 

1.  Exit HamClock, then click on the terminal icon at the bottom of the screen.

2.  Type the following command and press Enter: sudo nano /etc/hosts

3.  If asked for a password, the default Quadra password is 1n0v@t0 — note that both characters that look like the letter O are zeros. The password won't show up as you type it — that's normal, just type it and press Enter.

4.  Use the arrow keys to move to the bottom of the file and add this line:  

3.128.20.228    clearskyinstitute.com

5.  Press Ctrl+O (that's the letter O, not zero) to save the file, then press Enter to confirm.

6.  Press Ctrl+X to exit nano.

7.  Type exit and press Enter to close the terminal, then restart HamClock.

Instructions to update the backend to yet another HamClock project, Open HamClock Backend, will follow in a couple of days