Author: SM0TGU

Webmaster and member of the AMSAT-SM steering group.

Categories
Ham Satellite news Telemetry

CAS-6 active

In June 20 (2020) the CAS-6 satellite was activated. As reported by many it is only active for 1 sec in 7 sec interval. It can be seen in the beacons, both CW and GMSK.

I hope this can be fixed – CAS-6 is very strong on downlink and it can be a nice ham radio satellite.

Frequencies:

• CW Telemetry Beacon: 145.910 MHz
• AX.25 4.8kbps GMSK Telemetry: 145.890 MHz
• U/V Linear Transponder Downlink: 145.925 MHz, 20 kHz bandwidth, inverted
• U/V Linear Transponder Uplink: 435.280 MHz

Categories
Ham Satellite news

Raspberry Pi decoder now available

According to info from G3VZV/FUNcube website the FUNcube decoder now can be used with Raspberry PI, but only if you are using FUNcube dongle SDR.

Raspberry Pi decoder now available

Categories
Telemetry

AO-92 telemetry compare Fixed antenna vs Yagi

This is same pass from AO-92 at 20 degree elevation, decoded by my SatNOGS station and my “big” setup with tracking yagis. Good to see that the yagis makes a huge difference. Note: I’m not sure about the difference in data frames between the programs.

  • SatNOGS: Fixed antenna, Crossed Dipole (Turnstile), LNA and RTL-SDR v3.
    3 data frames decoded.
  • Tracking Yagis, 2 x 6 element with circular polarisation, LNA, Airspy Mini, SDR-Console v3, Fox telemetry software.
    27 frames decoded -> in DK3WN presented as 9 block/frames.
Categories
Antennas

V-dipole for UHF – build a simple satellite antenna

A V-dipole for NOAA weather satellites on 137 MHz has been published by 9A4QV and it seems to get very good results. I decided to build one for UHF 436 MHz satellite band and also add reflectors to get the antenna pattern higher up.

I followed the instructions by 9A4QV but adjusted to 436 MHz. All SWR measurements are done with a NanoVNA. Please see the pictures below for some ideas how to build one of you own. You can also see test results below.

I have used the following materials:

  • PVC pipe 32 mm diameter
  • TIG Aluminium elements (Tigrod ESAB OK 4043 (3.2 mm/1000 mm)
    In Sweden you can buy these at https://www.svetsmaskinservice.se/
  • Coax cable direct connection to the element
  • All elements are aprox 16 cm long. Make the two elements for the dipole a little longer and cut for best SWR
  • Distance to radioators are aprox 10 cm
  • As you can see I use a lot of glue to make it water proof… 🙂

Some pictures from building

Mounted at the same place as my VHF crossed dipole. I use these antennas for my SatNOGS station.

Test results

When listening to local repeaters a got good readings, but when trying to receive satellites I did not get the result I think this type of antenna should deliver. I think it is a better antenna for the high power NOAA satellites on 137 MHz. But, it´s very simple to build!

Some results:

Bugsat-1 RX by my SatNOGS station. Two packets decoded.
Video: Receiving RS-44 satellit while holding the antenna by hand
Categories
Ham Satellite news Members news

Olle Enstam SM0DY Silent Key

Olle Enstam SM0DY har avlidit i en ålder av 90 år. Olle var under många år aktiv i AMSAT-SM både som styrelsemedlem och ordförande. Han var även aktiv på satelliterna och en flitig skribent i medlemstidningen AMSAT-SM Journal.

Jag hade förmånen att vara medlem i styrelsen en tid under Olles ordförandeskap. Trots stor åldersskillnad mellan oss fick jag alltid förtroende av Olle vilket hans stora erfarenhet av styrelseuppdrag då lyste igenom.

I Svenska Dagbladet den 8 juni 2020 finns en minnestext som sammanfattar hans yrkesliv.

/Lars Thunberg SM0TGU

Categories
Telemetry

XW-2A CW telemetry 2020-06-01

RX CW decoding with fldigi.