Sdr rtl вот такое Г высылают некоторые китайцы. не покупать!
Been building antennas for Outernet use over the last couple of days, succeeded to get well over 3dB SNR required for downloads.
A truly portable a cheap - less than $1 total cost - antenna.
Also did some more tests of the Pro Stick Plus - versus other receivers and with different antennas.
Full construction details on radioforeveryone.com.
I got your N3 production unit out yesterday.
Feel free to review, write and post anything you care to."
Update Nov 13, 2016: added info to images due to comment.
Common wisdom is to place LNAs at the antenna.
Let's test a FlightAware's Pro Stick Plus against Premium dongles with LNA at the antenna, with long coax cable length.
Which setup gets more reports?
- two Raspberry Pi 3 from a ModMyPi Starter Kit, so identical back-end computing, system variance less than 2%.
Antenna is a half-wave telescopic commonly available with dongle bundles, on a metal tin. Normally, I get around 20,000 position reports with this antenna and short coax lengths.
No user involvement, and no gain adjustment in PiAware.
rtl-sdr.com v.3 used on Day 1, Nooelec SMArt on Day 2. Totals indicated.
Frankly, I'm just as surprised as you are, as I've only seen the results when double-checked which IP address belongs to which receiver combo.
15.17% percent more position reports with a Pro Stick Plus, which costs half as much as a premium dongle and preamp. Granted, it will be pretty much unusable for general use due to filtering, but the same 1090 MHz filter also does wonders for ADS-B reception.
Significantly less position reports than usual; other FA feeders in my area did not experience such a downturn, so the only explanation is long coax length. Minimize coax length for best signal, or completely eliminate it with direct connections.
Your location, preamp, antenna, cable and retina is different from mine. The "LNA at the antenna" mantra comes up so often that I wanted to see what happens for ADS-B use. That's all.
The fact is that a receiver built for a specific task with a preamp and filter, costing $21, beat a combo built for general use costing $46. Adding a filter for $20 might narrow the performance gap, but spending $66 when the same job can be done for $21 seems a bit stupid. If you can run coax to a remote location and mount an antenna there, you should be able to run Ethernet cable and mount Pi3 with PoE at the antenna. Ethernet cable is so much cheaper than coax.
I'm writing posts at the moment, and concurrently testing lots of equipment.
Some of the makers above offer similar products, so comparisons are unavoidable. And necessary. And the purpose of this blog.
I can't help it, so I'll tread on quite a few toes in the near future.
- homemade ADS-B antennas are great.
Plus many more, I'll try to catch up with posting, doing justice takes time. Watch this space, follow on twitter @rtlsdr4everyone for news.