Even if the satellite’s elevation angle is less than 1 degree or sometimes a negative elevation angle due to atmospheric refraction can lead to successful QSOs.
However, Gpredict does not allow the Minimum Elevation value to be set to less than 1 degree, and passes with a MEL of less than 1 degree do not appear in the Upcoming List, etc. This is unfortunate as it narrows the opportunities for communication.
I reported another bug in 2020 and was told that it would be fixed in the next release, but five years have passed and no new version has been released. This is also very unfortunate.
Tada/JA7KPI
Being able to call at low elevations has been a hit and miss matter for me.
In the past, there have been satellites which I could reach even before they came up over the horizon, such as AO-27. On the other hand, because I live in a large urban area, I generally allow a few minutes after the AOS time before calling. I usually start when the elevation’s about 10 degrees as the local topography has enough obstructions that my chances of reaching a satellite when it’s lower are pretty slim.
I found that it depends on the satellite and, sometimes, time of day. When HO-68 was active, I would listen for its telemetry beacon and when I could receive it, I switched over to the FM repeater frequency. By then, it was probably at least 10 degrees above the local horizon and well above most of the buildings in my neighbourhood.
If I tried about mid-morning local time, I often made contact with a ham in Vermont and, for about a minute or so, we had the satellite all to ourselves. After that, other stations started calling.
Low elevation passes allow long distance communication.
Satellites such as FO-29 and RS-44, which are at an altitude of about 1500 km, allow communication up to 8000 km.
In the past, I was able to communicate with OH ES 4J VE7 VE8 KI7(OR) via SSB/CW. I think the elevation angle of the satellites was quite low.
In addition, low elevation passes require a longer distance through the atmosphere, which can cause the radio waves to refract due to the atmosphere, making it appear as if they are arriving from below the horizon.
High elevation passes provide stable communication quality, but I want more thrilling amateur radio. Shouldn’t it be possible to set the minimum elevation value to around minus 2 degrees?
Tada/JA7KPI
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It would indeed be nice if one can have QSOs at such low elevation angles, but one also needs a suitable local geography. I have to set up my station on my balcony and I have to play hide-and-seek with nearby buildings to reach a satellite, unless it’s at a high elevation.
Recently, there were a number of articles relating to QO-100 that were published in The AMSAT Journal. A number of hams attempted to get onto that satellite from the island of Newfoundland and the articles outline how they were able to reach it.
Yes. Local geography is important. In my location, there are buildings facing Europe, so I sometimes rove to the coast to operate.
I was once able to access satellite even at an elevation angle of minus 2 degrees on a hill near the coast.
Not trying to be rude here. The code is open source.
The way this usually works is that you have a feature you think is good, implement it in the code and test it thoroughly and then make a PR describing the feature. Be prepared to test it additionally as the developers might see unintended consequences etc.
If the developers/project is very active this might be possible to feature request in an issue, but I would not count on that.
And yes, I have poked around in it and modified it to my needs before.
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