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LimeSDR

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Re: LimeSDR

#61

Post by touisteur »

syedkarim wrote: post #33
touisteur wrote: post #22

Earlier quoted context omitted.

It is very depressing indeed. Has eBay or second hand given good results on this to anyone? I guess we'll have to wait for https://www.crowdsupply.com/krakenrf/krakensdr but I can't imagine the price will be very light-hobby-adapted.

We are shooting for a price of $299 for KrakenSDR.

Oh thanks for your answer, that's very interesting! For someone wanting to upgrade from rtl-sdr that seems a good step up.

While you're here, I'm particularly interested whether you're aiming for something more ambitious some day or 100% focused on kraken? I'm thinking coherent 32/64 rx channels or more? Also, is there a way to assemble two krakens and synchronize them somehow so as to have 10x coherent rx? :-)

There's probably a better channel of communication for such questions ...

Thanks again for jumping in with a correction.

Re: LimeSDR

#62

Post by jjwiseman »

CSSer wrote: post #38
WrtCdEvrydy wrote: post #26

Earlier quoted context omitted.

The best one is the ADS-B Out from airplanes, you can map the planes around you with a $20 widget.

This sounds really cool. When you say 'around you', what kind of radius are we talking?

As others have said, it depends on terrain, your antenna, the altitude of the aircraft, etc. But generally, 50-60 miles is pretty easy with almost any setup.

I have an ADS-B antenna mounted on my roof that feeds into a filter and an amp, and I get less than 50 miles in some directions (because of mountains) and more than 150 miles in other directions (over the ocean).

Here's a map of my coverage (any altitude), with range rings every 50 miles: https://www.flickr.com/photos/wallofhair/51403416502

My coverage for altitudes up to 10,000 feet: https://www.flickr.com/photos/wallofhair/51404165241

It's radio, so nothing's guaranteed. Those maps show the maximum ranges at which I picked up any aircraft in that direction over a couple months, so they're kind of a best-case, showing when conditions possibly happened to be perfect. I also have a dead zone just around my house, because my gain is configured to prioritize range. Lots of tradeoffs in RF.

There's a site (with an impossible-to-remember name) that can predict antenna range for you (it's not obvious how to use it; Try "New panorama", then "Up in the Air"): http://www.heywhatsthat.com/

Here's what it shows for me. The blue ring is 40,000 feet altitude and the orange ring is 10,000 feet altitude: https://www.flickr.com/photos/wallofhair/51404944889

Re: LimeSDR

#63

Post by tjohns »

CSSer wrote: post #38
WrtCdEvrydy wrote: post #26

Earlier quoted context omitted.

The best one is the ADS-B Out from airplanes, you can map the planes around you with a $20 widget.

This sounds really cool. When you say 'around you', what kind of radius are we talking?

It depends on your location, antenna, and the aircraft's elevation, but in the bay area I'll often pick up aircraft all the way out to Sacramento. Sometimes quite a bit further.

Of course, the higher the aircraft the further you can "see" them. Most of the traffic I see is within 45 miles (especially low flying GA traffic), but I'll still pick up the occasional high altitude aircraft at 100+ miles out.

Re: LimeSDR

#64

Post by cschneid »

opwieurposiu wrote: post #32

SDR made me understand how much RF noise my desktop computer emits. Lots of spikes between 400-500mhz. Could be my monitor also, as scrolling text seems to emit the most noise.

There's a fun toy I just got called 'TinySA' (tiny spectrum analyzer). For $60, plus an adapter + some wire (another $20 maybe), you can get a live battery powered little receiver that shows noise across the whole spectrum from less than 1mhz through 350mhz.

A really basic loop of wire is a directional antenna, so you can narrow down exactly what is causing issues too.

I'm doing it to find noise issues for my ham radio setup, but it can be generally fun. Not quite an SDR, but to find noise sources it's pretty amazing for so cheap.

Re: LimeSDR

#65

Post by cschneid »

nlh wrote: post #14

I was super into the ham world many many moons ago (DE K2KD), and my curiosity is definitely piqued with the arrival of SDRs. Dumb question(s): Is it possible to do "traditional" HF/VHF ham stuff with these mini SDRs? Is there a good software package that emulates the old-school rigs (but with fancy new features)? Are these radios powerful enough to drive an amp to get to something like 100W (or 1500W) on HF?

Check out the Hermes Lite, it's an SDR with a transmit ability, and some other additional features. I think it's 10w by default, but a lot of people put that right into an amp to get up to 100+ watts.

Re: LimeSDR

#66

Post by IshKebab »

I got a LimeSDR when they first made them. Unfortunately the whole SDR software ecosystem is pretty terrible. Even with something as popular and widely supported as RTL-SDR most of the software is unusuable (with some happy exceptions). It also doesn't help that there is an absolute mountain of SDR software out there, but 99% of it is "this is cool, I'm going to write... eh nevermind" type stuff. There's so much ( https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/ ) that I can't even find the one good one I found last time I used an RTL-SDR.

I guess that is what happens if you play with software written by uber-nerds for uber-nerds.

Anyway in conclusion I would NOT recommend getting a LimeSDR unless you are really really into SDR and it's your only hobby, or better yet, your job.

Re: LimeSDR

#67

Post by gmiller123456 »

ambientenv wrote: post #55
gmiller123456 wrote: post #51

Earlier quoted context omitted.

Can you provide some resources about this?

There is the Blitzortung.org site - https://www.blitzortung.org/en/cover_your_area.php - which has some interesting information.

Thanks, but that link appears to be about dedicated modules. I already have a HackRF One and an RSPDuo, the person I was replying to seems to indicate it was possible to use a typical SDR.

Re: LimeSDR

#68

Post by platz »

IshKebab wrote: post #66

I got a LimeSDR when they first made them. Unfortunately the whole SDR software ecosystem is pretty terrible. Even with something as popular and widely supported as RTL-SDR most of the software is unusuable (with some happy exceptions). It also doesn't help that there is an absolute mountain of SDR software out there, but 99% of it is "this is cool, I'm going to write... eh nevermind" type stuff. There's so much ( ht…

as an early limesdr buyer i completely agree

Re: LimeSDR

#69

Post by dang »

Some past related threads:

Investigating the Galileo Satellite Navigation System Outage with a LimeSDR - https://news.ycombinator.com/item?id=20464852 - July 2019 (41 comments)

LimeSDR Now Backed by the European Space Agency - https://news.ycombinator.com/item?id=16493727 - March 2018 (38 comments)

LimeSDR Mini – An open, full-duplex, USB stick radio for femtocells and more - https://news.ycombinator.com/item?id=15318233 - Sept 2017 (46 comments)

LimeSDR funded, some hours left to still get a discounted SDR - https://news.ycombinator.com/item?id=11946239 - June 2016 (10 comments)

LimeSDR GSM Base Station Demo - https://news.ycombinator.com/item?id=11931072 - June 2016 (27 comments)

IoT wireless hacking – LoRa on the LimeSDR - https://news.ycombinator.com/item?id=11882491 - June 2016 (1 comment)

Digital Video Transmission using LimeSDR and GNU Radio - https://news.ycombinator.com/item?id=11856912 - June 2016 (8 comments)

LimeSDR: Flexible, Next-Generation, Open Source Software Defined Radio - https://news.ycombinator.com/item?id=11610521 - May 2016 (28 comments)

Re: LimeSDR

#70

Post by drmpeg »

jacquesm wrote: post #21
nlh wrote: post #14

I was super into the ham world many many moons ago (DE K2KD), and my curiosity is definitely piqued with the arrival of SDRs. Dumb question(s): Is it possible to do "traditional" HF/VHF ham stuff with these mini SDRs? Is there a good software package that emulates the old-school rigs (but with fancy new features)? Are these radios powerful enough to drive an amp to get to something like 100W (or 1500W) on HF?

Before you start pumping out that kind of power I'd invest in a spectrum analyzer (which are surprisingly affordable today) to ensure that the signal that goes out is clean. Those mini SDRs when used for transmission will output a ton of harmonics because they are almost by definition not going to have any filtering on their output because that would limit their usability. When used for reception that is not a proble…

That's for sure. Here's what an Ettus B210 (now $1472, not cheap) looks like with a fundamental at 145 MHz. 3rd harmonic is only 10 dB down. Power was 0 dBm (with a 20 dB pad on the analyzer input).

https://www.w6rz.net/harmonic.png

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