Amateur Radio – Page 3

August 31, 2021October 1, 2023

ISS Contact

A few months back, I purchased an Arrow II satellite antenna so that I can get better results when the International Space Station has their SSTV events. There are usually only a handful of events each year, and I’ve missed most of them since the first one I participated in back in February 2019.

The station has its own APRS setup, so I decided one night to see if I could ping it with my equipment. I used APRSDroid on my phone and linked to one of my UV-5R radios. All that needed to be done was to change the APRS digi path in the app preferences menu to ARISS and set the frequency on the radio to 145.825 MHz. All I could do then was to eagerly wait for the next pass of the station overhead.

SUCCESS!

The following image shows the contact. Only 1 packet made it through, though I had made several attempts during the pass. The packet was digipeated back to Earth through KE8FZT. This was a fun experiment and I look forward to attempting it again with my big old tripod I dug out of storage a few weeks back. Should make things a bit easier going forward.

Screencap shows the default ISS position out near the west coast of Africa (it’s always there). It was almost directly overhead when the contact was made.

Note: Yep, don’t start a post while you’re falling asleep. It’ll end up sitting as a draft for a few months if you do.

March 31, 2021March 31, 2021

20 Years of ARISS SSTV Event

Back in December there was an SSTV event to celebrate 20 years of amateur radio operations on the International Space Station. I was able to catch part of an image from a fairly good pass, but abruptly lost the signal.

Since then I have purchased an Arrow II Satellite Antenna. Should be getting better results next time.

March 31, 2021

Solar Box Update

A quick little update on this project.

I left the solar box outside for 3 weeks from January to February 2021, seemingly the coldest part of the winter. Temperatures dipped to -23 Celsius at the lowest without the wind chill.

In order to give the box something to do, I hooked up a USB reading lamp to the 12V USB adapter. It wasn’t pulling a crazy amount of power (only 0.05A). The kit managed to keep going, discharging a bit each night and recharging during the few hours of sunlight it had during the day. One handy thing about the light being hooked up was that I could see if the kit was still on without having to go outside.

It only died once that I’m aware of and the next day it came back to life after a few hours of sunlight hitting the panel. That was 2 days before I brought it back inside.

Almost Dead — Getting pretty close to shutting down.

The battery was not able to fully charge each day due to a combination of the cold, some heavy snowfall and overcast days during those 3 weeks. On a sunny day, the sun was hitting the panel for about 3-4 hours per day, which would normally be enough to fully charge the 7A battery during the warmer months, but not enough in the winter. I could’ve adjusted the charge controller to have a higher float voltage to compensate for the cold temperatures (currently set at 14.1 V). The only problem with this is that I would have to manually adjust it anytime the ambient temperature got too high. Not much of an issue in this situation, but it would be an issue if this was deployed throughout multiple seasons (ie: 6 months from January to June). 14.1 V is a good float voltage for 20ish degree weather. Setting it higher to compensate for the cold winter weather would keep it topped up better in the winter, but would lead to the acid in the battery boiling during the warmer months, thereby killing the battery.

My initial thoughts about increasing the amperage by adding another battery in parallel would possibly prevent the float voltage adjustment from being necessary in such situations.

When I brought the kit back inside, the battery was not fully charged. Charging it with the solar panel in the window for about a month did not do much to bring the battery back up to full capacity. It did get really warm here over the last few weeks and so I set it back up outside. Within a few hours, the battery was fully topped off again.