Observation 707114: MAX VALIER SAT (42778)


#1

Regarding Observation 707114

I finally had confidence in my observations and came out of testing.

Dimitris is the first to schedule an observation from the community so thanks for that.

My results in testing were, to be honest, a little disappointing. That said I am using the very basics. A slim-jim made from 300 Ohm ladder line isn’t really the best. Plus I have hung said ‘aerial’ on the trellis on the side of the bungalow.

The addition of a 25dB pre-amp and boosing the RF Gain in settings has helped tremendously.

Well and truly bitten by the bug and if the boss allows it I will be improving the aerial!!


#2

I used to build proper Slim Jim antennas in my younger days. The property we liked the most is that the main lobe is at the horizon, Zero degrees which made it a great performer for terrestrial work but lousy for satellite work. Even a simple horizontal dipole will outperform a Slim Jim for satellites.
Regards Bob vk2byf


#3

Try it horizontally.


#4

Thanks Bob. I will give horizontal a try…


#5

Did trying the Slim Jim horizontally help?
I have one I am testing and want to improve reception.


#6

Hi,
It did a little, particularly because at the time I was limited to eastern passes only . I did see some improvement generally but this improvement was more pronounced in western passes.
The biggest benefits I have found (in my limited experience) was to add some RF Gain in the setup/advanced parameters (remembering to use a value supported by your SDR) and to add an LNA.
My LNA uses a 12V DC supply. Had I researched a little first I would have tried the broadband LNA from RTL-SDR Blog using the bias tee power option from my RTL-SDR V3. This is what I am working on setting up at the moment.
I hope this helps.

Michael


#7

Looking at some of your observations, I found that you are not exactly centered in frequency, may be could be your problem
Look at the beginning of this: https://network.satnogs.org/observations/828588/

73’s


#8

Maybe I can help here having had rtl-sdr problems and solutions.

  1. if you have a genuine V3 rtl-sdr you don’t need to add RFgain. Let the hardware AGC take control.
  2. if you have a genuine V3 rtl-sdr you won’t need to set PPM by more than 1 or 2 if at all to be centred in the waterfall. Run rtl_test -p this will give you a rough idea wether you have a genuine or fake rtl-sdr. The fakes are usually a long way off frequency and have a lot of drift. The fairdinkum ones are very close. Have a look at my station 568 & 724. I must admit a LNA at the antenna helps.
    73 Bob vk2byf

#9

Thanks for the advice Bob. It makes a lot of sense and I think Amazon may have sold me a blag V3.
Kalibrate informs me that I am +31 off frequency and try as I might I cannot get the bias tee to turn on for my new LNA.
I know it’s far from ideal but my current LNA is near the Pi as it requires 12V DC. My new LNA should use 5V DC supplied by the bias tee and I can then move it to the antenna.

Michael


#10

Ask for a refund as you were sold a fake.
I bought though fleebay and lodged a return and got a FULL refund.
I bought 2 new ones from https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
plugged them in no gain setting no PPM setting and they work. I may have to buy another for my dump1090 setup.
Another thing, RPis in aluminium box to reduce the noise generated and also be careful what power supply you use for 5V DC. I had S9 noise from 3 buck regulators.
Have gone back to inefficient but quiet analogue 338k, 3 terminal regulator.
Good results now on GS 568 and 724
73 Bob vk2byf