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Jon Harder

@ng0e.bsky.social
93 followers 62 following 104 posts

Creator and maintainer of • vhf.dxview.org • hf.dxview.org

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Jon Harder @ng0e.bsky.social · 20/09/2026
The HF propagation map has a new feature that shows the past week of amateur radio activity for each dxcc entity. At a glance one can see what bands and modes are being used. As an example, see the charts for Kenya: hf.dxview.org/activity/430 #hamradio
A set of colorful charts showing recent amateur radio activity from Kenya. The display is divided between activity during the past day and another for the past week.
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Jon Harder @ng0e.bsky.social · 13/08/2026
ALERT: the dxview propagation maps will be offline Friday starting around 0930Z to try another hardware combination. It should be off only a few minutes. hf.dxview.org vhf.dxview.org #hamradio
"Computer CPU 960x854" by char1iej is licensed under CC BY-NC-ND 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-nd/2.0/?ref=openverse.
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Jon Harder @ng0e.bsky.social · 11/08/2026
I recoded this again. A very small script is loaded in the head. The script at the end of the body loads all the scripts in the right order using promises and then does the initialization after all the scripts are loaded. What do think of this solution?
Javascript snippet
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Jon Harder @ng0e.bsky.social · 05/08/2026
ALERT: the dxview propagation maps will be offline Thursday starting around 0930Z to transition to new server hardware and new database. Hopefully the downtime will be less than two hours, but it is possible that unforeseen problems will extend that time. hf.dxview.org vhf.dxview.org #hamradio
Server room. Credit: Tristan Schmurr, https://www.flickr.com/photos/kewl/
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Jon Harder @ng0e.bsky.social · 16/06/2026
The HF+ propagation map at hf.dxview.org now has a view of DX Clusters. Look for it in the main menu. #hamradio
A map centered on Europe showing DX Clusters. Clusters are represented by colored circles (red, orange, yellow) indicating connectivity to the select node, GB7VAX.
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Jon Harder @ng0e.bsky.social · 21/01/2026
A new starting page has been created for the HF+ propagation map. Like the VHF page released earlier, it explains the purpose of the site and explains what it does. A new features allows users to set the perspective by providing a callsign. hf.dxview.org #hamradio
A screenshot the new HF+ propagation map home page showing sections labeled "View map", "About", "News", "Donations", "Amateur Radio", and "Sources".
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Jon Harder @ng0e.bsky.social · 31/12/2025
The VHF propagation map now has a descriptive starting page. It offers several ways to enter the map and more details about the site. vhf.dxview.org #hamradio
A starting page layout divided into multiple sections titled "View map", "About", "News", "Donations", "Amateur Radio", and "Technologies".
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Jon Harder @ng0e.bsky.social · 16/12/2025
Donations cover the server, network bandwidth and other incidental expenses for providing the VHF and HF maps. Thanks to all who have donated! Direct donation link: www.paypal.com/donate/?host... HF map: hf.dxview.org VHF map: vhf.dxview.org #hamradio
A donations popup that includes a yellow bar graph indicating the current funding level.
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Jon Harder @ng0e.bsky.social · 16/12/2025
The propagation maps recently added a heart icon for donations that appears when the funding level falls below 100%. The heart becomes more red as the funding level falls. When the level is below 50% a donation dialog will pop up about once a day for each user. #hamradio
Map icons that include a red heart for access a donations menu
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Jon Harder @ng0e.bsky.social · 19/11/2025
When the "connected" option is used, all the connections in a region are exposed and station labels are suppressed. The keyboard shortcut c-click is equivalent. 3/3 vhf.dxview.org #hamradio
A VHF propagation map showing the interconnecting hops of many stations arching over a region in Europe.
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Jon Harder @ng0e.bsky.social · 19/11/2025
Selecting the "multiple" option allows station selections to accumulate. The keyboard shortcut alt- or option-click is equivalent. 2/3 vhf.dxview.org #hamradio
A VHF propagation map showing two different stations selected simultaneously.
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Jon Harder @ng0e.bsky.social · 19/11/2025
ANNOUNCING: The VHF propagation map has more options for showing hop details. Upon selecting a station's footprint a "details" menu pops up offering "single", "multiple", or "connected" views. 1/3 vhf.dxview.org #hamradio
A VHF propagation map showing a new popup menu for selecting station details.
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Jon Harder @ng0e.bsky.social · 15/11/2025
There are now two ways to bookmark the HF+ propagation map: By band: hf.dxview.org/band/14 — set the band to the given MHz. Valid band numbers are 1, 3, 5, 7, 10, 14, 18, 21, 24, 28, and 50. By location (grid square): hf.dxview.org/perspective/... #hamradio
Browser address bar showing link to a particular perspective.
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Jon Harder @ng0e.bsky.social · 12/11/2025
An update to the VHF propagation map has been uploaded. It has a number of fixes including better representation of activity that is adjacent to the international dateline, particularly for New Zealand. vhf.dxview.org #hamradio #newzealand
VHF propagation map show activity between Aukland and Wellington, New Zealand.
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Jon Harder @ng0e.bsky.social · 18/10/2025
Another followup to this — if you hold down the "r" (for recursive) key and select a footprint, it will expand to all the connected paths. To reduce clutter station callsigns are omitted. You may need to refresh your browser to pick up the change.
APRS paths spanning from the Great Lakes to the Atlantic
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Jon Harder @ng0e.bsky.social · 25/09/2025
Happening now: I think this is legitimate propagation from Wichita to northern Mississippi. Can anyone on the ground confirm? vhf.dxview.org #hamradio
VHF propagation map showing activity from Wichita to northern Mississippi.
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Jon Harder @ng0e.bsky.social · 25/09/2025
There is a new button on all devices to reveals a propagation prediction between two points on the HF map. To show the prediction, first select an initial location. Next select a distant point of interest. Finally, at the top of the window, select "show prediction …". hf.dxview.org #hamradio
A propagation prediction chart for 14 MHz between the grid squares PM35 and PI58.
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Jon Harder @ng0e.bsky.social · 25/09/2025
Enhancements for mobile devices have been completed for the HF propagation map. Most visitors to the HF map are using a phone or tablet. The experience on phones and tablets is much improved now. The changes will be activated the next time you open or refresh the site. hf.dxview.org #hamradio
A HF prediction for the 14 MHz band centered on Asia as captured by a phone screenshot.
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Jon Harder @ng0e.bsky.social · 18/09/2025
The HF map is most useful when your location is selected because it personalized the map for your QTH.
3.5 MHz propagation map showing a starred perspective location as seen on a phone screen.
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Jon Harder @ng0e.bsky.social · 18/09/2025
The draggable target for selecting your station's location has been slimmed down (same on mobile and desktops) and the corresponding text input moved to the top of the screen. Panning or zooming the map under the selector now correctly updates the targeted location.
18 MHz propagation map showing western Europe and featuring a draggable target and text input field for selecting a station location, as shown on a phone screen.
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Jon Harder @ng0e.bsky.social · 18/09/2025
ANNOUNCEMENT: the process of optimizing the HF+ propagation map for mobile devices has started. The app is working much better on small screens now. The band selection bar appears conveniently at the top of the screen. hf.dxview.org #hamradio
10 MHz propagation map showing western Europe on a phone screen.
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Jon Harder @ng0e.bsky.social · 12/09/2025
The VHF propagation map is working much better for mobile devices now. A significant number of visitors use mobile or tablet devices and this will greatly improve their experience. Let me know if something should be working better! vhf.dxview.org #HamRadio
VHF propagation map of central Europe.
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Jon Harder @ng0e.bsky.social · 05/09/2025
ANNOUNCEMENT: the VHF propagation map is being optimized for tablets and mobile devices. It is working much better for the smaller screens. There are a few differences between mouse- and touch-based interaction: vhf.dxview.org #hamradio
Screenshot from a phone showing VHF propagation centered on Germany.
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Jon Harder @ng0e.bsky.social · 04/09/2025
The VHF propagation map will start showing more activity. A coding error when translating from Rails to Rust caused some activity to be filtered inappropriately. vhf.dxview.org #hamradio
VHF propagation map of the NE USA.
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Jon Harder @ng0e.bsky.social · 31/08/2025
Today some corrections and enhancements were applied to the VHF propagation map. The changes improve the interaction as the pointer is moved over active stations. A white outline adds contrast to the footprint and when selected the paths are clearly revealed. vhf.dxview.org #hamradio
A VHF propagation map highlighting a station in Turkey.
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Jon Harder @ng0e.bsky.social · 29/08/2025
ANNOUNCEMENT: The HF propagation map now has an option to display the gray line. This feature is activated with a checkbox in the main menu. hf.dxview.org #HamRadio
HF propagation map showing the gray line feature and the associated menu option.
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Jon Harder @ng0e.bsky.social · 19/08/2025
Of all the the lighthouses on the air this past weekend, 7S0SFJ in Sweden is one of the unique ones. The station is on the "Finngrundet," a lightship that was in service from 1903 to 1969. www.sjohistoriska.se/en/visit/the... #hamradio #lighthouse
"Lightship No. 25 Finngrundet" in port.
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Jon Harder @ng0e.bsky.social · 27/07/2025
Here is an unexpected mid-ocean HF propagation data point. KQ6RS reports this WSPR equipped buoy drifting in the North Atlantic is a high school project. During your station's off time, set up WSPR on 20m to see if it picks up the 0.01W signal! www.qrz.com/db/KQ6RS hf.dxview.org #hamradio
A yellow buoy with solar panels and antenna bobbing in the ocean. KQ6RS photo.
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Jon Harder @ng0e.bsky.social · 25/07/2025
VY0ERC is another far-north amateur operation on the HF propagation map. The club station is at the Eureka Weather Station on Ellesmere Island in Nunavut (Canada). Listen for them on FT8. FT8 activity: rbn.telegraphy.de/activity/VY0... Ellesmere propagation: hf.dxview.org/perspective/... #hamradio
Three musk oxen in a snowy landscape. VY0ERC photo
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Jon Harder @ng0e.bsky.social · 24/07/2025
I see what is going on. It will take a while to implement, test and upload the new code. Maybe in 12 hours it will be fixed.
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Jon Harder @ng0e.bsky.social · 24/07/2025
Have you ever wondered why the HF map has propagation from the far north? Polarstern is a German polar research vessel. It is active as DP0POL using WSPR on 7, 10, 14, and 18 MHz. Today it is above 84º N latitude. Follow DP0POL on WSPR: www.wsprnet.org/olddb?mode=h... hf.dxview.org #hamradio
The German polar research vessel Polarstern as it navigates sea ice.
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Jon Harder @ng0e.bsky.social · 18/07/2025
The prediction produced when "MUF" is selected at the top of the map shows which band has the best signal for each hour of the day. A color coded area at the bottom shows the optimal frequency. By moving the pointer across this area the band number is indicated in the middle of the prediction box.
An HF prediction chart between EN23 and EK38 showing which bands are best. A colored band along the bottom associates hour of the day with the optimal band.
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Jon Harder @ng0e.bsky.social · 18/07/2025
When an HF propagation prediction finds that long path signals will be stronger, they are used in the chart. Gray bands indicate when long path is used. Long path denotes a signal that is strongest coming the long way around the world (180º from the expected direction). hf.dxview.org #HamRadio
HF prediction chart between EN23 and QL32 showing gray bands indicated when long path is better.
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Jon Harder @ng0e.bsky.social · 18/07/2025
The HF propagation predictions charts are working better after correcting errors introduced in the conversion to Rust. The chart shows hours of the day going from left to right, starting at 0000Z (UTC). The red vertical bar is the current time. Color coding shows SSB, CW, FT8 or WSPR. #HamRadio
HF propagation chart between grid squares EN23 and EM71, showing hours 0000Z to 2400Z on the 18Mhz band. The chart is color coded showing SSB, CW and FT8 levels.
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Jon Harder @ng0e.bsky.social · 13/07/2025
Drawing areas of propagation that cross the 180th meridian (International Date Line) on the HF map have always been a mathematical challenge. A bit ago an update was uploaded that finally gets it right (I think). Errors had been showing up particularly on 20 meters. hf.dxview.org #hamradio
A man stands on the International Dateline in Fiji with the left side labeled "Today" and the right side "Yesterday."
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Jon Harder @ng0e.bsky.social · 09/07/2025
The HF propagation map is now running on all Rust code. An error in the activity view resulted in missing data, including a blank map for 10 Mhz. That and some other minor things have been fixed. hf.dxview.org #hamradio
A map of activity on the 20m amateur radio band showing station C94RRC in Mozambique.
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Jon Harder @ng0e.bsky.social · 02/07/2025
Ever since switching the VHF (APRS) data gathering app to Rust there has been a persistent memory leak. I finally had time to dig in and resolve the problem. Now it stays around the 150-160M range. In contrast the HF data gathering app, sits around 100M. vhf.dxview.org #hamradio
View of aprs app status showing 158.6M memory in use.
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Jon Harder @ng0e.bsky.social · 01/07/2025
The VHF site was having problems related to file compression on some older Safari browsers. I believe that is all sorted out. Compression is fairly easy to implement with the Rust system being used, but leave it to me to overthink things. vhf.dxview.org #hamradio
Rust line of code: .wrap(Compress::default())
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Jon Harder @ng0e.bsky.social · 27/06/2025
The HF+ propagation map ( hf.dxview.org ) is most useful when you select your location by clicking on the map (or entering your grid square, if you know it). This allows you to see where in the world you are likely to make contacts on any band. #hamradio
Map showing HF propagation on the 20m band.
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Jon Harder @ng0e.bsky.social · 27/06/2025
The VHF propagation map ( vhf.dxview.org ) has recently completed conversion to the Rust language, away from Ruby on Rails. It is very fast and is improving as performance updates are applied. #hamradio
Map of VHF propagation for the upper midwest of the US.
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Jon Harder @ng0e.bsky.social · 27/06/2025
I am an amateur radio operator who maintains the real-time HF+ and VHF propagation sites. The HF map has two modes: global activity per band and propagation unique to the user's location. The VHF map is useful for showing areas of enhanced propagation, typically tropospheric ducting. #hamradio
Map showing current propagation on the 20 meter bandMap showing current VHF propagation.
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