Regarding Observation 3396013 …
I have a V-Dipole antenna with a nooelec reciever and the satnogs station image on a raspberry pi. Right now I dont even have one good observation the dipole has a low recitance(to the cabel) additionaly the antenna is facing north(for nooa) and the image is working as intended.Does anyone have anyone have any ideas why this keeps happening?
Increase RF gain with satnogs-setup, you use default value.
Did you determine the PPM calibration value?
is there a good value to go with?
no i did not let’s try it
You should do a frequency calibration. I have a Nooelec instance that has frequency error 198kHz on 144MHz, so I was not receiving any signal.
Find any continuous broadcast signal (using GQRX for example) that has a carrier and you know the nominal frequency of, and adjust the PPM value until its peak in the spectrum display is centered on that frequency value.
You can use Kalibrate-RTL program also, that uses GSM mobile cell phone base stations to determine the PPM offset, by using the GSM signals own frequency correction bursts.
I did that though the documentation lacks a little for the new satnogs build and got an average absolute error if -0.311 ppm (it is only a test run inside not the final number) do I now have to write + or -1 into my configuration?
I started with a v-pole that came with RTL-SDR and that antenna is just ok. A ground plane antenna I’ve had for a year, with a space blanket has been amazing. See this page for details on that setup.
Some good NOAA:
To get the most out of the v-pole, the length of the antenna are very specific to 137 MHz. I got a cheap VNA device and tuned the antenna and was very surprised at how precise the length of each side had to be. Mine was adjusted to about 51.9 cm, metal only, for a good resonance over 135 to 145.
I clamped the V-pole on a table south, over an overhang or down from deck to ground about a meter or so to the ground.
You could also try flipping the ears over if the RHCP polarity is correct. I definitely got some partial NOAA images with the v-pole. This is my first good pass with the v-pole.
If you are in a city and noisey RF area, don’t get the antenna up high; it may be best lower to the ground and shielded by some trees and buildings. It seems bad because you get less line of sight, but you are only looking for the strongest signal when the distance to the sat is at minimum.
I had better luck with the gain turned up I run my ground plane maxed out at 49.6 on the RTL-SDR. I cannot remember what I did on the v-pole but probably a little above avg.
Don’t worry about the calibration with RTL-SDR; these radios are almost always close to perfect; I tested all three of mine and one was off by -1, the others were 0. I don’t know about your brand, but your observation looks to me that the signal is there but weak. Face south and trim antenna length, check if flipping antenna changes it. And a wide angle, such as 120 to 140 degrees, angled up from ground level at about 10 to 15 degrees.
Another way to learn is to hook your SDR to your mac or windows computer and play with it with the 1 or 2 top most popular software. If you can watch a NOAA pass live with the waterfall try playing with your antenna placement, then trim your antenna length! Playing with the SDR software on windows if you have it will give you the most joy and learning.
The v-pole will also pickup other 140 MHz signals. With the v-pole I did eventually get a little data from FOX-1B, C, D, and ISS. It was cool to have ISS self-identify with the v-pole…
Checkout my 1169 ground station with a $30 antenna and space blanket. That is a trouble-free install. It would be hard for me to do any better without going to a rotator with cross-yagi.
Good luck and message or let us know what you figured out!
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No. You can:
- increase Nooelec RF gain;
- install LNA as close to the antenna as possible, especially if you have a very long feedline or a cable with high attenuation.