Category: Antennas

A Video Tutorial about Receiving HRPT Weather Satellite Images

Over on YouTube 'Tysonpower' has recently uploaded a very informative video and blog post showing how he is able to receive HRPT weather satellite images. Note that the video is in German, but English subtitles are provided.

Most readers of this blog are probably familiar with the more commonly received APT images that are broadcast by the NOAA satellites at 137 MHz, or perhaps the LRPT images also broadcast at 137 MHz by the Russian Meteor M2 satellite. HRPT signals are a little different and more difficult to receive as they are broadcast in the L-band at about 1.7 GHz. Receiving them requires a dish antenna (or high gain Yagi antenna), L-band dish feed, LNA and a high bandwidth SDR such as an Airspy Mini. The result is a high resolution and uncompressed image with several more color channels compared to APT and LRPT images.

In his video Tysonpower shows how he receives the signal with his 3D printed L-band feed, a 80cm offset dish antenna (or 1.2m dish antenna), two SPF5189Z based LNAs and an Airspy Mini. As L-band signals are fairly directional Tysonpower points the dish antenna manually at the satellite as it passes over. He notes that a mechanised rotator would work a lot better though. For software he uses the commercial software available directly from USA-Satcom.com.

[EN subs] HRPT - Erste Bilder! und mein Setup

An Example HRPT Image Received by Tysonpower.
An Example HRPT Image Received by Tysonpower.

Using a Slinky as a Cheap Antenna for the 80m Band

A slinky is a fun little toy that is essentially a long and loose spring. You can perform tricks with them, but the most iconic use is making them walk down stairs all by themselves. Over on Hackaday we've seen a tutorial that shows how to use a slinky as a good antenna for the 80m (3.5 MHz) band. Using a slinky as an antenna is nothing new to hams, but the original post on imgur shows some pretty clear photos and instructions on how to construct one.

The text written by the original poster on imgur notes that he uses this antenna very successfully with his RTL-SDR in direct sampling mode and this even outperforms his regular shortwave radio. He notes that slinkies aren't weather proof, so some sort of weather proofing spray coating or oil might be useful for a permanent set up.

If you are interested apart from the discussion on Hackaday there is also a comments thread on Reddit where the original poster discusses what he purchased.

Slink Antenna for 80m
Slinky Antenna for 80m