Архив за 12.10.2019

Need help improving my turnstile antenna

Hello! I post this because I only pick weather satelltes when their elevation is huge. I use a turnstioe antenna. The measurements are ok, and the pashing section works ok. Howevee, I am not getting good SWR.

These measurements were taken with a NanoVNA:

https://imgur.com/9VTQHgL

https://imgur.com/26skpdw

I did not add any matching line to the beginning of the antenna, and now everything is sealed with silicone. Is there anything I can build to solve this?

Picture of the antenna:

https://imgur.com/C8TG8Oq

73, Thanks!

Edit: If this were a simple dipole, I would add a balun. However, due to the falt that they are tho dipoles with different phases, I am not sure wether that would help or not. Besides, would shortening the output coax length and connecting the antenna to the next stage (filter or LNA) with the shortest length possible improve the SWR?

submitted by /u/pkmpad
[link] [comments]

Antennas • Re: Antenna location question

It is still caught inside the house, which was built in the late 70s or early 80s when it was on fashion to hide all plumbing inside the walls and use concrete reinforced with rebar 'grates'. So it's really not a house built for people having radio-reception as a hobby :) (And for some reason putting up an antenna outside is not allowed anymore. Hopefully that fashion will change again one day and the look of an antenna will be perceived as something beautiful. I wouldn't mind, but radio-people are a minority these days)

Later I will try to experiment with a loop and perhaps also with sticking a ground-spear deep into the garden.

Statistics: Posted by JEL — Sat Oct 12, 2019 9:00 pm


Troubleshooting Help • Re: Error: Cannot access RTL device

darrenyorston wrote:
Mon Apr 24, 2017 6:01 am
I kept uninstalling the device driver via COntrol Manager and deleting the SDR# folder. After doing this four times SDR# is now working. Pretty annoying.

The driver is shows to the left is WinUSB (v6.1.7600.16385). Its the same one it installs. Windows 10 detects it this way by default.

Only thing I have noted is that the WCID checkbox is always showing a red cross. Under Windows 8.1 it always showed a green tick.
Having Same issue. used to be a Green Check now a red X and my RTL-SDR stops working. I can get it to work for about 1 Second if I unplug it and plug it back in. Not sure whats happening.

Statistics: Posted by Winmocktor — Sat Oct 12, 2019 8:25 pm


RTL-SDR Discussion • RTL-SDR Stops working

My RTL-SDR has suddenly stopped working. I have noticed when I unplug it then plug it back in it will work for about 1 second then suddenly stop. Not sure what is causing this. Anyone else have the same issue or know a possible cause?

Statistics: Posted by Winmocktor — Sat Oct 12, 2019 8:07 pm


Antennas • Re: Antenna location question

30 ft is close to fullwave for 10 m (1/4 lamda is ~2.5 m) so the wire should work down to about 40 m.

However if it is close to your house and it is shielded as you wrote, it will influence reception and resonance.If you have metall tubes (water/heating) you can try to use them as ground and see if this helps.

Statistics: Posted by snn47 — Sat Oct 12, 2019 7:06 pm


Which antenna should I get?

I have just ordered the rtl-sdr blog's device. But since you can't order it with the antenna kit from my local reseller I now need an antenna. Since I am an absolute beginner I have no idea what I should be looking for. I don't want to spend more than 20€ on it. I thought it should not be too hard but I have not found a single one on ebay or amazon yet that looks good. What should I search for? I live in Germany btw, so some things may not be available but please post them anyway since I might at least get a clue what I could search for. Thank you!

submitted by /u/ujasd8731ejksc0n32cq
[link] [comments]

Signal Identification Help • Re: Schedules ?

Where are you from?

Statistics: Posted by Username — Sat Oct 12, 2019 7:56 am


Troubleshooting Help • Re: Rasberry Pi running 2x Dongles

Hi
Thats why I use an Win Server there I could use multiple Sticks at the same Time.

Statistics: Posted by Username — Sat Oct 12, 2019 7:45 am


Recording Meteor satellites with GQRX on Linux

I cannot find any concrete information about recording and demodulating/decoding the images on linux. I am no expert and I have no idea if I'm just doing something stupid. It seems to me that everybody does it their own way, and that's fine.

To start, I use a cheap moxen antenna I made in a few minutes that works great for NOAA. This very well could be my problem, but I get a fat signal in the waterfall when it's overhead, so I feel like I should be getting at least something. Where I'm at is that I record a .raw file from GQRX at an input rate of 1920000. I don't know if this is too high or wrong. I don't quite understand what it is either. I fiddled with it and decimation but 1920000 or 2400000 without decimation works well for noaa. I don't quite understand what decimation is either but I kind of have a feel for what it does. I couldn't find it documented for gqrx, IIRC it said just leave it and you'll be fine.

I found a convenient sox command to convert the recorded .raw into a .wav file.

sox -S -e floating-point -b 32 --endian little -c 2 --rate 2400000 gqrx_raw.raw -r 130000 -b 16 -e signed-integer result.wav

This works well without any issues. I demodulate it and I do not see a proper constellation. It's more of a diagonal line that flips back and forth. When I decode that, I get a 0 byte image.

I am going to try glrpt tomorrow, but I like gqrx and use it for NOAA sats as well so it would be convenient for me to use the same program.

Basically, this is stuff I found from various sources and through trial and error. If anybody currently uses gqrx for meteor satellites and has a workflow that works from recording + recording settings all the way to a final image, please share what you know. Thanks.

submitted by /u/TheRoosterDog
[link] [comments]

2 Dongles on Rasberry Pi

Ive been trying to get 2 USB dongles to work together, When I run them separatly they work fine but when I try to run both together in 2 separate terminals the first one stops working and the 2nd doesn't work at all.

The following is the terminal output for running 1 only:

---

rtl_fm -f 148.982M -s 22050 -d 0 | multimon-ng -t raw -a POCSAG512 -e -f alpha /dev/stdin >FRNSWpager.txt | sudo python3 /home/pi/FRNSW.py multimon-ng 1.1.7

(C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
(C) 2012-2019 by Elias Oenal
Available demodulators: POCSAG512 POCSAG1200 POCSAG2400 FLEX EAS UFSK1200 CLIPFSK FMSFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV X10 SCOPE
Found 2 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001
1: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner Tuner gain set to automatic.
Tuned to 149235575 Hz. Oversampling input by: 46x.
Oversampling output by: 1x.
Buffer size: 8.08ms Exact sample rate is: 1014300.020041 Hz
Allocating 15 zero-copy buffers Sampling at 1014300 S/s.
Output at 22050 Hz.
POCSAG to Email Converter V1.1
Decoding POCSAG signals...

---

When I try to run the second one in terminal I get this and no output from both:

---

pi@raspberrypi:~ $ rtl_fm -f 148.582M -s 22050 -d 1 | multimon-ng -t raw -a POCSAG512 -e -f alpha /dev/stdin >xyzpager.txt | sudo python3 /home/pi/xyz.py multimon-ng 1.1.7
(C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
(C) 2012-2019 by Elias Oenal Available demodulators: POCSAG512 POCSAG1200 POCSAG2400 FLEX EAS UFSK1200 CLIPFSK FMSFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV X10 SCOPE
Found 2 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001
1: Realtek, RTL2838UHIDIR, SN: 00000001
Using device 1: Generic RTL2832U OEM Found Rafael Micro R820T tuner
POCSAG to Email Converter V1.1
Decoding POCSAG signals...
Tuner gain set to automatic.
Tuned to 148835575 Hz.
Oversampling input by: 46x.
Oversampling output by: 1x.
Buffer size: 8.08ms
Exact sample rate is: 1014300.020041 Hz
Allocating 15 zero-copy buffers
Failed to allocate zero-copy buffer for transfer 8
Falling back to buffers in userspace
Sampling at 1014300 S/s.

Output at 22050 Hz.

---

I can't bring either online again until after I have rebooted.

Also does anyone know what the command for a graphed output is (I used to use it to check squelch levels)? I have done it previously but can't remember or find it anywhere.

submitted by /u/jeffengo
[link] [comments]
Перевод
Рубрики
Архивы
Октябрь 2019
Пн Вт Ср Чт Пт Сб Вс
« Сен   Ноя »
 123456
78910111213
14151617181920
21222324252627
28293031