Connecting Antenna via Coax Already In House

FlightAware ADS-B Flight Tracking
41

@mwshell What about this shopping list?

  1. J Pipe Mount for Antennas, 39"
  2. RTL-SDR Triple Filter LNA
  3. Power inserter (<$10)
  4. Weatherproof junction box (to house the RTL-SDR LNA)
  5. a few ft (or what is needed to get to junction box) of coax with N-connector (antenna) and SMA-(male) BEWARE: not RP-SMA). something like this or this.
  6. FE1090-P antenna or a COL1090/5-P/S
  7. SMA(male) to F (female) adapters to hook up the LNA and power inserter to the existing coax cables using F-connectors (4-pack)
  8. Velcro cable ties
42

This is my RTL-SDR BLOG Triple Filter LNA + Chinese Bias-T at eBay

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Tripple Filtered LNA-1R
Tripple Filtered LNA-1R660×530 69.6 KB

 

Tripple Filtered LNA-2R
Tripple Filtered LNA-2R628×533 86 KB

 

Bias-T at Amazon

https://www.amazon.com/Broadband-10-6000MHz-Microwave-Blocker-Amplifier/dp/B081SY89L8/

 

43

This is close to what I was thinking.

  1. Two sections of 2" PVC cut to 2’ with a 45 degree elbow in the middle
  2. RTL-SDR Triple Filter LNA (Amazon)
  3. Power Inserter
  4. Bias Tee
  5. Junction Box (I like the one you found, but will need to double check dimensions)
  6. FE1090-F antenna (It has an F mount, so I can just use regular coax without having to worry about an N connector)
  7. Filter Adapters you recommended
44

@mwshell Do not use the power supply you linked.
It is a 12v supply. The LNA is 5v max.

45

Are there 5V power inserters or would that be more if a DIY soldering project?

46

I’m guessing it’d be more like this:

with this

1 Like
47

You will need lot of F-female to SMA-male adaptors OR Pigtails

CAUTION: Do NOT purchase RP-SMA

 

https://www.amazon.com/s?k=F-female+to+sma-male+adapter

https://www.amazon.com/s?k=F-female+to+sma-male+cable+pigtail

 

image … image

48

This Bias Tee says 1-50V 0.5 Amps Max. If the power supply is 2 amps, isn’t that a problem?

49

If I recall correctly @keithma used this bias-t for his installtion. He can tell his experience with it.

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I use the one in the photo below and this also says max 50V, 500 mA

2. Working parameters
1. Frequency range: 10 - 6000MHz
2. Insertion loss: 0.3dB@512MHz 0.45dB@1575MHz
3. Maximum voltage: 50V
4. Maximum current: 500mA
 

image

50

You could always power the bias-t from the usb socket on your raspberry pi. The USB port provides 5v. Usb cables are cheap, just cut one to the appropriate length and solder the power wires to the bias-t. (This is what I have done).

No, that is not a problem. The power supply rating of 2 amps is its maximum output current but the LNA will not draw more than the 0.5A rating of the bias-t. The power supply will not force current into the LNA because it is rated at 2A. The LNA will just draw what it needs.

2 Likes
51

That is the one I use too. It works just fine.

52

Yup, that looks exactly like the one I used.

If it helps, there’s a complete breakdown of everything I used, including all the inter connections on my blog post here.

53

2 amps power supply means it is capable to supply up to max 2 amps, but will actually supply only the load demanded.

500 mA bias-t means it can safely draw up to 500 mA from power supply and feed 500 mA to the load (amplifier).

The RTL-SDR BLOG Triple filter LNA has load of 150 mA, which is well within limit of the bias-t capacity of 500 mA.

RTL-SDR Blog Triple Filter LNA Specification:

  • Frequency: 1090 MHz
  • Gain: 27 dB @ 1090 MHz
  • Return Loss: -16 dB @ 1090 MHz (SWR = 1.377)
  • Noise Figure: ~1 dB
  • Out of band attenuation: More than 60 dB
  • ESD Protection: Dual with GDT and ESD Diode
  • Power: 3.3 - 5V via bias tee only, 150 mA current draw
  • Enclosure: Aluminum enclosure
  • Connectors: Two SMA Female (Male to Male adapter included)

 

54

I would not recommend this one if you have zero to none experience with soldering electronics (I presume you don’t). The inserter @abcd567 uses perhaps looks a little less fancy without the casing, but it is much easier to install. If you don’t like the esthetics, there are probably seperate casing available for it.

As @LawrenceHill mentioned, instead of buying an extra power supply you can use an USB-cable. You can strip an USB cable from an old keyboard, mouse, extension cable, etc.

There are four wires inside an USB cable; in general the colours used are Red, Black, White and Green.

Cut the white and green cables, they are for data. The power cables are red (+, VCC, positive) and black (-, GND, ground, negative), connect them accordingly to the terminal of the Bias Tee inserter (aka power inserter, biaser) and plug in the USB cable to an empty USB socket of the Pi.

EDIT:
This biaser is fine, too:

1 Like
55

Rats. I thought it was just a plug and play. I thought the power connection was one that was plugged into a DC adapter. I’ve soldered before, but its been a long time and I wouldn’t call myself experienced. I think this thread has shown that while it’s possible, I think my inexperience isn’t doing me any favors. Getting my pilot’s license was easier than this! :laughing: One thing I have learned though, keep your cable runs short!!!

3 Likes
56

Use RTL-SDR Blog Dongle V3. It has built-in Bias T, and gets power from RPi. No need for any external power supply & bias-t.

Another dongle with builtin Bias-t is by NooElec.
https://www.nooelec.com/store/nesdr-smartee-sdr.html

RTL-SDR Blog System
RTL-SDR Blog System759×355 3.06 KB

1 Like
57

How are these different from the FlightAware Pro Stick Plus, which also has a built in amp and filter?

58

None of the two have integral amplifier or filter.
Both these are Generic DVB-T with enhanced temprature stability + Bias-T

The “Triple filter LNA” will be sufficient to do both the the jobs of amplifying & filtering.

I have run a scan of a Generic DVB-T alone, then same DVB-T fitted with RTL-SDR Triple Filter LNA. (Both scans with dipole antenna inside the room, Gain setting 49.6 dB, scan range 24 MHz ~ 1800 MHz)

Generic DVB-T (No internal/external Filter or Amplifier)

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Generic DVB-T + Triple Filter LNA

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59

Ok, considering pulling the trigger. Here’s my shopping list, all on Amazon. Because if it doesn’t work out, I can just send it back…

  1. NESDR SMArTee v2 SDR - Premium RTL-SDR w/Integrated Bias Tee
  2. ADS-B LNA High Performance Triple Filter Low NF Amplifier
  3. SMA Male to F Type Female RF Antenna Cable Connector Coax Adapter
  4. Waterproof IP68 External Junction Box
60

Great shopping list.

I am not sure if RTL-SDR Triple Filter LNA passes dc to antenna port. Some one who has checked this can tell.

In case the LNA passes dc to antenna port, then while selecting an antenna, select one that does not have a dc short. In case you select an antenna with dc short, add a dc blocking capacitor between LNA and antenna.