Архив за 09.09.2018

Comment on Othernet (formerly Outernet) Updates Lantern Backers by Szarka

At this point I’m not believing this is ever going to happen. Pretty much ignoring them now. Too bad.

Off-Topic • Re: Where do you buy these tiny aluminum enclosures?

Dear admin can I have the size of them?
Is there an discount when I order ~15pcs?

Statistics: Posted by Username — Sun Sep 09, 2018 10:53 pm


Off-Topic • Finding a signal frequency Via type of antena

Hi. i am new to sdr. i am trying to find my local emergency sirens frequency. i know from the manufacturer that it can be either UHF or VHF activation via DTMF codes. now, this is the yagi antenna mounted on the siren its self. dose it Looks like its tuned to UHF or VHF? trying to get a Direction where to scan...



Image
Image

Statistics: Posted by Hoshen_Kadosh — Sun Sep 09, 2018 10:53 pm


How long do GOES image downlinks take?

Due to a large forest in my backyard that mostly obscures LOS to GOES16 the only place where I can put an antenna is in my front yard right next to the sidewalk. This makes it difficult to keep the antenna permanently mounted so I was planning on just storing it somewhere and taking it out/aiming it whenever I have time/when there's something interesting (hurricane season). I'm also using an Ubuntu VM on a Windows laptop instead of a raspbi as I figured I didn't really need the pi if it wasn't going to be permanent. So my question is how long would I have to be sitting in my front yard w/ my laptop for an image?

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

RTL-SDR Discussion • Re: Help withRTL-SDR & SDR# No Device Selected error

Thank you for the reply.

Although the batch file launches, nothing additonal happens. When I viewed the batch file line entrys, the refenced url reported as invalid.

http://osmocom.org/attachments/download ... ebInfo.zip tmp\RelWithDebInfo.zip 404s on any system I have access to here.

I did a google search and downloaded the .zip file (sorry, I don't remember where, off hand).

Then, I went through and did each step of the batch file manually. rtlsdr.dll was copied into the SDR# folder, too.

If there's a specific location for the .zip file you'd like me to download, please share a URL and I'll download it there.

-Mark

Statistics: Posted by mlange — Sun Sep 09, 2018 10:12 pm


Signal Identification Help • Re: Splatter, noise or ? 450.675 MHz

That looks like some variant of 4FSK. Did you pick up this signal near a restaurant perhaps? I think some pagers use this exact frequency.

Statistics: Posted by Airwind — Sun Sep 09, 2018 9:45 pm


Signal Identification Help • Re: 433mhz waveform. FSK? GFSK? GMSK?

Looks like 2FSK to me. The two peaks are the two alternating frequencies.

Statistics: Posted by Airwind — Sun Sep 09, 2018 9:38 pm


Comment on SDR# TETRA Decoder Plugin Updated by Sergi

I have the same problem with exactly same system.

Maximum USB cable length

Question often comes up, Answer: 27 feet / 9 meters with RTL-SDR dongles:



For testing, I tried four separate RTL-SDR dongles in image above: rtl-sdr.com v3, Nooelec Mini 2, Nooelec E4000 SMArtee and regular Nooelec SMArt.
USB connector cable is crucial, as mentioned in a previous post detailing stuff I'm happy with, blue 5 feet / 1.5 m USB connector with ferrites were used. Tried several USB connectors over the years, these worked best, 27 feet / 9 m connectors totaled 5 dollars off eBay.



Computers were a Lenovo and a ThinkPad, identical results, all computers provide 5V to USB devices, so host computer should not matter.

Noise pickup


Nope at these extreme lengths, in fact, better with once section of USB cable as receiver is moved away from computer, didn't see any noise pickup from 5 feet /1.5 m to 27 feet / 9 meters.

Try not to use coax below 20 feet / 6 meter


If distance between antenna and receiver is within these lengths, substitute coax with USB cables. Cheaper, and since signal received is immediately chewed into digital ones and zeros, there's no chance of electrical noise pickup by coax cable.
Doubtful? Check printscreens of various lengths, top image without any USB cable connection, then adding one section (5 feet / 1.5m) at a time.
Really, I can't see any changes between the second image from top (one section) and the last image on the bottom (5 sections).




RTL-SDR Dongles Image Gallery

Studio Photos of over 20 RTL-SDR dongles on the market:


More than 200 high-resolutions PCB, case and comparison images by clicking here.
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