diff --git a/content/blog/prop1.md b/content/blog/prop1.md index 454a818..5644a78 100644 --- a/content/blog/prop1.md +++ b/content/blog/prop1.md @@ -4,35 +4,39 @@ date = 2026-04-18 draft = false +++ -How can microwave contacts be made non-LOS is a question I've had for a while now. -From running a WISP I'm very familiar with point-to-point microwave links. However, -amateur radio operators have been making NLOS contacts for years when they technically -shouldn't work at all. +How to make microwave contacts non-line-of-sight (NLOS) is a question I've had for +a while now. From running a WISP I'm very familiar with point-to-point microwave +links. However, amateur radio operators have been making NLOS contacts for years +that technically shouldn't work at all. -As an example, this is the elevation path between my QTH and an [NTMS beacon on top of Texas -Women's University's dorm building](https://prop.w5isp.com/beacons/dddca785-c3e7-45f8-8f9f-edc748f881d6): +As an example, this is the elevation path between my station and an [NTMS beacon on top of Texas +Woman's University's dorm building](https://prop.w5isp.com/beacons/dddca785-c3e7-45f8-8f9f-edc748f881d6): ![Path profile](/images/path_profile.png) -This lead to a deep rabbit hole to investigate why contacts work some times and HOW they work. -There are already known propagation methods such as EME (moonbounce) or rain / meteor scatter, -however it's also possible to form ducts within the lower levels of the atmosphere with favorable -conditions. An easy to understand demonstration is why sometimes ships appear like they're floating: +This led to a deep rabbit hole to investigate why contacts work sometimes and HOW they work. +There are already known propagation methods such as EME (moonbounce), rain scatter, and meteor +scatter, but it's also possible to form ducts within the lower levels of the atmosphere with +favorable conditions. An easy visual analogy: ships sometimes appear to float above the horizon. ![Atmospheric ducted ship](/images/atmospheric_ducting.jpg) -This is because there's a duct with favorable conditions for refracting visible light -- the same -thing happen for microwave. +This is because there's a duct with favorable conditions for refracting visible light — the same +thing happens with microwave signals. -At one of the [NTMS](https://ntms.org) meetings, KM5PO presented about this same thing and had used -claude to write out some client-side pages to help predict and analyze the propagation. It was based -on limited data, but did an okay job guessing at why the propagation worked. +At one of the [NTMS](https://ntms.org) meetings, KM5PO presented on this exact topic and had used +Claude to write some client-side pages to help predict and analyze the propagation. It was based +on limited data, but did an okay job guessing at why the propagation worked. That talk is what +kicked off this project. -Fast forward a few weeks and I've now build an elixir/phoenix app at that -collects and processes everything. For a quick import of some known contacts made, I imported all -of the ARRL 10 GHz and up contests as well as the 222 MHz and up contests. +Fast forward a few weeks and I've now built an Elixir/Phoenix app at that +collects and processes everything. For a quick import of some known contacts, I pulled in results +from the ARRL 10 GHz and Up and 222 MHz and Up contests — VHF/UHF/microwave events where stations +log long-distance contacts on those bands. -With known contacts in place, it was time to backfill them with data, including: +With known contacts in place, it was time to backfill them with data. To predict ducting we need +atmospheric data at fine vertical resolution, so the app pulls from a mix of weather models, +surface observations, upper-air soundings, and terrain: ### Atmospheric * HRRR (NOAA 3 km) — hourly f00–f18 propagation scoring hot path; native hybrid-sigma levels for fine-grained duct detection @@ -58,17 +62,20 @@ have now been backfilled with this information. Feeding all of this in to Claude [algorithm](https://prop.w5isp.com/algo) that understands and can predict future conditions based on weather data. -This algorithm gets turned in to code, and then we can fetch HRRR data hourly, amend with ASOS -when available and feed it through the algorithm to determine if any given area's atmosphere is -favorable to propagation. Our predictions are still estimated and may not have any bearing on -reality. +This algorithm gets turned into code, and then we can fetch HRRR data hourly, amend with ASOS +when available, and feed it through the algorithm to determine if any given area's atmosphere is +favorable to propagation. The predictions are still experimental and not yet validated against +enough real-world contacts to be trusted. -Now our mission is to continue collecting as many verified contacts on 50 MHz and up and enrich -to refine our prediction model gradually over time. Another sub-project is automated beacon -monitoring. Any NLOS beacon that can be automatically monitored continuously provides an enormous -amount of data to train our model with since both points are known. +Now our mission is to continue collecting as many verified contacts on 50 MHz and up (the bands +where ducting and other exotic modes are most useful to amateurs) and use them to refine the +prediction model gradually over time. Another sub-project is automated beacon monitoring. Any +NLOS beacon that can be monitored continuously provides an enormous amount of training data, +since both endpoints are known and fixed. -The effort to expand has been growing and we now have help from a senior meteorologist in Lubbock, -Tx and many hams helping submit verified contacts. If you'd like to help out, we need as many -contacts during non-contest times as possible and future automated beacon monitoring. You can reach -me at my first name at my last name dot me (it's in the footer.) +The effort has been growing and we now have help from a senior meteorologist in Lubbock, TX and +many hams submitting verified contacts. If you'd like to help out, we need as many contacts as +possible during non-contest times — contest weekends concentrate activity into a few days, but +the model needs samples spread across all conditions. We also need volunteers for future +automated beacon monitoring. You can reach me at my first name at my last name dot me (it's in +the footer).