radio propagation

3 Articles

New LoRA Distance Record: 830 Miles!

September 15, 2023 by 52 Comments

The LoRa radio communication system is useful for low-bandwidth communication, and as many readers will be aware its special skill lies in delivering long range. For most of us that range tops out at a few miles, but pushing the limits of what is possible for LoRa has resulted in some significant records falling. Most recently this has reached an impressive distance of 1336 kilometres, or 830 miles.

The record in question was set from near the Portuguese coast, from where LoRa beacons on a fishing boat and its buoys were able to open up a gateway on the Spanish Canary islands. The conductive surface of the sea makes an excellent aid to propagation, and from amateur radio experience we’d guess that tropospheric conditions aided by the summer weather would have something to do with it too.

Radio amateurs on those coasts and islands chase those conditions and live in hope of making a rare UHF contact across the ocean to the Americas or the Caribbean. The difference in their respective frequency allocations notwithstanding, we wonder whether the same might be possible using LoRa given a fortuitous atmosphere. We’re not quite sure whether a set of dual-band LoRa gateways could be made to test this idea though.

This record breaks a previous one set between Germany and Poland. If you think you’ve seen a far greater LoRa record here before you’d be correct, but only in the modulation scheme and not the frequency.

Solar Flares And Radio Communications — How Precarious Are Our Electronics?

December 30, 2020 by 38 Comments

On November 8th, 2020 the Sun exploded. Well, that’s a bit dramatic (it explodes a lot) — but a particularly large sunspot named AR2781 produced a C5-class solar flare which is a medium-sized explosion even for the Sun. Flares range from A, B, C, M, and X with a zero to nine scale in each category (or even higher for giant X flares). So a C5 is just about dead center of the scale. You might not have noticed, but if you lived in Australia or around the Indian Ocean and you were using radio frequencies below 10 MHz, you would have noticed since the flare caused a 20-minute-long radio blackout at those frequencies.

According to NOAA’s Space Weather Prediction Center, the sunspot has the energy to produce M-class flares which are an order of magnitude more powerful. NOAA also has a scale for radio disruptions ranging from R1 (an M1 flare) to R5 (an X20 flare). The sunspot in question is facing Earth for the moment, so any new flares will cause more problems. That led us to ask ourselves: What if there were a major radio disruption?

Continue reading “Solar Flares And Radio Communications — How Precarious Are Our Electronics?” →

Crowdsourcing The Study Of An Eclipse’s Effect On Radio Propagation

August 17, 2017 by 23 Comments

If you are an American, you’ll probably now find yourself in one of three camps. People who are going to see the upcoming solar eclipse that will traverse your continent, people who aren’t going to see the eclipse, and people who wish everyone would just stop going on incessantly about the damn eclipse.

Whichever of those groups you are in though, there is an interesting project that you can be a part of, an effort from the University of Massachusetts Boston to crowdsource scientific observation of the effect a solar eclipse will have on the upper atmosphere, and in particular upon the propagation of low-frequency radio waves. To do this they have been encouraging participants to build their own simple receiver and antenna, and make a series of recordings of the WWVB time signal station before, during, and after the eclipse traverse.

This is an interesting and unusual take upon participation in the eclipse, and has the potential to advance the understanding of atmospheric science. It would be fascinating to also look at the effect of the eclipse on WSPR contacts, though obviously those occur in amateur bands at higher frequencies.

If you are an EclipseMob participant, we’d love to hear from you in the comments. Does your receiver perform well?

Thanks [Douglas] for the tip.