Observation 1946303: DIWATA-2 (43678)

Regarding Observation 1946303


How would you rate this pass ? I have a light trace at 220s that could indeed look like FM.

Leaving it as is for the time being.

Thank you !

73’ s Martin 9V1RM

The issue with DIWATA-2 is that it’s a FM repeater, and hence isn’t necessarily active at all times.

Looking at other observations from your station, it looks like you might have a high noise floor (or an antenna issue).
Your station: CAS-4B - https://network.satnogs.org/observations/1947399/
Another turnstile station, same sat, similar elevation pass: https://network.satnogs.org/observations/1947183/

You might want to look at placement of the antenna, what other electrical devices are in the vicinity, etc…

Mark VK5QI

Hi Mark,

Thanks for your input. It’s indeed interesting.

There are a few things I can most probably enhance, others I won’t be able to :

  • Whatever I do my noise level will be higher. More people leave in 9V1 than in the whole of QLD and as such the noise level is higher. Cheap LED are all over the place and there is not much I can do in terms of real estate to move the antenna around.

  • I have slightly amended the antenna. It’s a 3 elements turnstile and that may be too much. I have removed the director and will see if that flattens the main lob and gives me better signal at lower elevation. I have about 16 to 35 dB RL between 137 MHz and 148 MHz.

  • talking about lower elevation, 9V1 being just 1 degree North of the Equator is also one of the cities in the world with the most lightening registered. I would love to have the antenna on top of a big tower, but unfortunately, there is a metalic roof about 4m away from it and that blocks satellites when they are below 30 degrees anywhere from 280 to 70 degrees azimuth. Other directions are also not perfectly unblocked.

  • LNA : it’s interesting as I also happen to be using a similar LNA. Unfortunately mine so far is attached directly to the RTL-SDR key and not shielded => I’m waiting for some waterproof boxes to move the LNA close to the hotel and shield it properly. That should prevent any kind of auto-oscillation. The pictures to VK4XSS’s station show some great shielding and grounding for all elements. That’s definitely not the case here.

  • I have some high quality 10mm coax but I believe that may be a little overkill as all I have to cover right now are 7m using LMR-240. On 2m that should be ok.

73’s Martin 9V1RM