Keeping HamClock Alive
A free, community-operated backend server so your HamClock keeps working past June 2026. Point it here and forget about it.
WB0OEW — Silent Key
HamClock was created by Elwood Downey, WB0OEW — an engineer who built one of the most popular shack displays in amateur radio and gave it away for free. Elwood became a Silent Key on January 29, 2026.
I first reached out to Elwood back in August 2019. I told him I thought HamClock had real potential beyond the shack — that it could be a product, a service, something bigger. He wrote back:
"No, it's not exclusive at all. You could use my source and do the same thing if you want, no problem. That's the weird thing about open source software. You don't make money from the code itself. You make money by adding value."
That conversation stuck with me. I registered hamclock.com that same year.
Life got in the way. Years passed. When Elwood became a Silent Key and the June 2026 shutdown was announced, I knew it was time to act. This backend server — keeping your existing HamClock running — is and will always be a free community service. That's a promise.
Elwood's final release, version 4.22, included the -b flag — a backend override that lets any HamClock point at an alternate server. He gave us the tool and the time.
This server exists because of Elwood. I intend to keep his work running for as long as there are hams who depend on it.
A Personal Note from Bruce, W4BAE
I want to thank everyone who has donated their time helping troubleshoot issues, and those who have contributed through PayPal to help cover the backend hosting costs. This community has been incredible.
Let's be honest about what people actually want: they want their HamClock to work. They don't want to stand up their own server. They don't want to learn git. They don't know Linux server administration and they shouldn't have to. The "just self-host it" crowd makes it sound simple — clone a repo, run a script, done. It's not. This backend pulls from over 25 upstream data sources. Satellites get deorbited and new ones launch. NOAA changes their API formats. Data feeds get moved, blocked, or restructured without warning. It will take frequent curation to keep this thing running cleanly, and it is highly unlikely that any individual is going to roll a perfect solution on their own and keep it that way. I made it so that all you need is the -b flag and you're done. That's it. Your clock works. I handle the rest.
I refuse to believe the person who created HamClock wanted it to die with him. And here's what tells me that: the -b flag. Elwood sat down and wrote code — actual new functionality — to let HamClock point at an alternate backend server. That's intent. He wanted someone to pick this up. He gave us the tool and the time.
So here we are, carrying it forward. And then I get emails like these that make all of it worth it:
He even offered to donate hardware and invited me to speak at his club.
That's what this community is supposed to look like. Thank you for riding along.
How to Migrate
Earlier versions of this page suggested editing /etc/hosts to redirect clearskyinstitute.com to this server. That method is no longer recommended. Please switch to the -b flag using the instructions below.
For neatness, also remove the clearskyinstitute.com line from your /etc/hosts file once your HamClock is launching with -b hamclock.com:80.
HamClock 4.22 (the final release) includes a -b flag that lets you point it at any backend server. No software changes, no reflashing, no firmware updates — just add the flag wherever HamClock launches on your device.
The Quick Version
Stop your running HamClock.
Restart it with the backend flag pointing to this server:
That's it. Your HamClock will pull all data from hamclock.com instead of clearskyinstitute.com. It will survive the June 2026 shutdown.
The -b flag is available in HamClock version 4.22, the final release. If your HamClock auto-updated, you already have it.
Desktop Linux / macOS
Just add the flag when you launch:
Raspberry Pi — Systemd Service
If your Pi runs HamClock as a systemd service (most common), edit the service file:
Find the ExecStart line and add the -b flag:
ExecStart=/usr/local/bin/hamclock
# After:
ExecStart=/usr/local/bin/hamclock -b hamclock.com:80
Then reload and restart:
$ sudo systemctl restart hamclock
Don't Know Where Your Startup Config Is?
Run these commands to find it:
$ systemctl list-units | grep -i hamclock
# Check crontab:
$ crontab -l | grep -i hamclock
# Check autostart (desktop):
$ cat ~/.config/autostart/hamclock.desktop
# Check rc.local:
$ cat /etc/rc.local | grep -i hamclock
# Find the binary itself:
$ which hamclock || find / -name "hamclock*" -executable 2>/dev/null
Once you find the line that launches HamClock, add -b hamclock.com:80 to the end of the command.
Raspberry Pi — Crontab
If your Pi starts HamClock from crontab:
Find the HamClock line and add the flag:
@reboot /usr/local/bin/hamclock-fb0-1600x960
# After:
@reboot /usr/local/bin/hamclock-fb0-1600x960 -b hamclock.com:80
Raspberry Pi / Inovato Quadra — Desktop Autostart
If HamClock launches automatically when your desktop loads:
Find the Exec= line and add the flag:
Exec=/usr/local/bin/hamclock-1600x960
# After:
Exec=/usr/local/bin/hamclock-1600x960 -b hamclock.com:80
Reboot the device and HamClock will pull from hamclock.com on every start.
Pre-Built Raspberry Pi Image (Coming Soon)
I'm building a ready-to-flash Raspberry Pi image with HamClock pre-configured to use hamclock.com. Write it to an SD card, boot your Pi, and you're done — no command line needed. A Raspberry Pi 4 or Pi 5 with 2–8 GB of RAM provides significantly more headroom than the Inovato Quadra's constrained hardware, and makes an excellent dedicated HamClock display. Check back here or email bedrich@citrinet.com to be notified when it's available.
Need Help?
If you're not comfortable editing config files, forward this page to a tech-savvy friend or local ham club member. All they need to do is find the line that starts HamClock and add -b hamclock.com:80 to it. Or email me at bedrich@citrinet.com with your setup details and I'll walk you through it.
HamClock 4.23 — Coming Soon
A new HamClock release is in the works. Watch this page for details on what's included and how to upgrade. If you'd like to be notified when it's available, email bedrich@citrinet.com.
Data Feed Status
Every feed listed below runs independently — no dependency on clearskyinstitute.com. Data is sourced directly from NOAA, NASA, USNO, Open-Meteo, PSK Reporter, and other primary providers.
VOACAP — Side by Side
Same transmitter location (South Florida), same time, same parameters. The VOACAP engine here was rebuilt from scratch using cubic interpolation. The original used nearest-neighbor on a coarse rectangular resample — hence the blocky 90° staircase artifacts. Click either image to enlarge.
If your MUF-VCAP map looks different from what you're used to, check the SSN value shown in your HamClock header — this backend uses the current daily sunspot number, which may differ from what your previous server was providing.
About This Server
hamclock.com is operated by Bruce Edrich, W4BAE (CISSP, CPTS) — a cybersecurity consultant and ham radio operator based in South Florida. The backend started as a fork of open-hamclock-backend (OHB), an open-source project by Brian, KO4AQF and Austin, KN4LNB, who reverse-engineered the original server API from scratch. Their work provided the foundation — I've since rebuilt and extended it into a fully independent production backend.
Major work beyond OHB includes: rewriting the VOACAP propagation engine with cubic interpolation and per-user dynamic generation, building a real-time PSK Reporter stream ingester pulling 400+ spots/sec directly from origin infrastructure, weather pressure maps in both millibar and inHg units at five resolutions, aurora and DRAP map generation, real-time MUF overlays, Kp/Bz/Dst/X-ray feeds from NOAA SWPC and Kyoto WDC, curated satellite TLE catalog with dead birds removed, VOACAP response caching for sub-100ms repeat queries, and hardening the entire server for production use serving thousands of HamClocks on AWS.
Every data feed now runs independently — this server has zero dependency on clearskyinstitute.com and will continue operating without interruption after the June 2026 shutdown.
No tracking, no paywall. Just a server that answers when your HamClock calls.
Troubleshooting
HamClock Crashes After Running for a While
If HamClock runs fine for a period then suddenly crashes to the desktop, the most common cause is your SD card or internal storage filling up from HamClock's log files. This is especially common on the Inovato Quadra, which ships with very limited onboard storage and RAM, and on older Raspberry Pi models (Pi 3A/3B) with small SD cards.
SSH into your device and check disk usage:
$ free -h
If any partition is at or near 100%, that's your problem. Clear the old logs:
Reboot and HamClock should stay up. To prevent this from happening again, you'll want to disable HamClock's logging permanently.
Can't Ping the Server
This is normal. The server is hosted on AWS, which blocks ICMP ping by default. If you want to verify the server is up, use your browser to visit hamclock.com — if the page loads, the server is running.
Public IP Shows Blank on Startup
This usually means HamClock couldn't reach the server at the moment it started. Check your internet connection and try restarting HamClock. If the server was briefly down for maintenance, a simple restart will resolve it.
VOACAP DE_DX Shows Only Grid Lines
If the VOACAP reliability map shows latitude/longitude lines but no propagation data, try selecting a different band. Some bands have zero propagation at certain times of day — the map will appear mostly dark or empty when there's nothing to show. Switch to a band with active propagation (20m and 15m during daylight hours are usually a safe bet) to confirm the feed is working.
Still Stuck?
Email bedrich@citrinet.com with your hardware (Pi model, Quadra, Mac, etc.), your HamClock version, and what you're seeing. Screenshots help. I'll get back to you.
Acknowledgments
This server wouldn't be where it is without the people who showed up early, kicked the tires, and told me what was broken.
Don, W8CPT, has been an invaluable tester. Jos in the Netherlands caught an international weather bug that led to a complete overhaul of the weather feed. And to everyone who has donated to help keep the lights on — thank you. Every contribution is appreciated and goes directly to keeping this server running. You know who you are. 73.
Get in Touch
Questions, problems, want to help? Reach out.
Keep the Lights On
This server runs on AWS and costs real money every month. If HamClock matters to you, consider helping keep it online. Every dollar goes directly to hosting costs.
Support hamclock.com via PayPalPayPal: paypal.me/bruceedrich