Friday, 30 August 2013

Review: LNA4ALL Antenna Amplifier

What is it?

LNA, RTL-SDR, SDRSharp, ADSB, Weather Satellites, AIS, antenna, setup, testing, review, comparison, DIY, Homebrew,

A small electronic device making radio signals 100-150 times stronger.
Officially called a low-noise amplifier, LNA for short.
Costs 25 euros delivered, helps you hear and see more targets of interest.

Why?


- To run the RTL stick with less gain,
- To get the maximum from your antennas,
- To add range to your reception ability.

Testing setup

Commercial radio, airplane speech, Weather satellite signals, AIS and airplane position signals are tested. If the LNA delivers as promised on these frequencies, we can assume that it will also perform in the band of your interest.
Antenna is a broadband, commercially-available discone to eliminate antenna errors.
No number-crunching for the review, check the images for exact dB values.
I paid for my LNA, and have no business connection with the manufacturer.

Commercial radio / Upconverter range
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Signal strength increase as promised.
This band if of particular interest to those who have an upconverter for shortwave reception.

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Performance slightly better than expected.
Airplane chatter between Plane and Approach/Tower/Ground comes booming in, much better audio, pilot seems talking to you.
Also tested with an Icom IC-R5 handheld receiver, no need to use outside discone as clear reception indoors.

LNA, RTL-SDR, SDRSharp, ADSB, Weather Satellites, AIS, antenna, setup, testing, review, comparison, DIY, Homebrew, NOAA, APTWeather Satellites / NOAA APT reception


Signals are visibly stronger in the waterfall display (quickly connected the LNA during a recent pass), less banded noise in images, same noise floor requires less gain in SDRSharp.
As less gain is required, the stick runs cooler, less internal noise is generated, images are clearer.  

Marine Band / AIS
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Increased gain step-by-step until all four vessels in port showed up in Shipplotter, first by MMSI, then by name.
Amplifier connected only half the gain was necessary, performance on par with manufacturer specification.


Airplane position signals / ADSB
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Without ampifier, maximum range is 46nm (83km).
With the LNA, maximum range is 52nm (94km).
ADSB Sharp with Tuner AGC on, adsbScope for monitoring, maximum range and aircraft not dropped selected. Monitoring local traffic for few hours and using range rings to establish maximum range, all equipment including antenna height (4 metres or 12 foot) the same during testing.


Ordering and customer service 


Contact the seller, Adam directly via email for orders: adam9a4qvwashington@yahoo.com/ Remove the capital of the USA to get his real email: name (4letters) and callsign (5 characters).
Seller only charges you when the item arrives, no worries over items getting lost. Payment via Paypal.
Shipping to Ireland took 5 working days, amplifier in a bubble wrap envelope with drawings.
Communication is good, questions via email answered quickly, technical shortcomings revealed openly.
Amplifier worked out of the box.

What you get


A small circuit board, no power supply, no instructions where goes what, no clue how it works except for a diagram showing components and performance.
If you know radio, soldering and electronics, it will make sense, if not, you will turn your 25 euros around, wondering what to do with it and where to start.
The manufacturer states that a "Turn a key solution is delivered" - that's not true. You have to provide power to it.
Note to manufacturers: Please send boards - or make it an option - with a red and black wire for power connector. This nonsense with USB connectors, pins and holes should stop. 

How to make it work

LNA, RTL-SDR, SDRSharp, ADSB, Weather Satellites, AIS, antenna, setup, testing, review, comparison, DIY, Homebrew, NOAA, APT(This is my solution, LNA operational in 10 minutes. Solder if you can or want to)
In the envelope you get a drawing, bottom left of the page shows a picture of what you have, with writing such as GND and + 8-15VDC.
Get a small screw, screw it into the third hole from the left BY HAND.
Too much power = too big screw.
Screw goes through = small screw.
Easy does it, should be just a little bit of resistance as you turn.
That screw is electrical power, plus on your battery.
All the holes in the four corners are negative, minus sign. Use screws, this time falling through the hole, to create four legs, similar to an oil rig.
Create support so the screws to hold the board in place - use a non-conducting material. Ideas: cigarette filter tips (works), scrap plastic from coax cables (might need multiple layers), wall plug fixings (currently in use).
Connect a wire to the screw sticking out from the positive, third hole from top left, by wrapping the wire around it. Write plus sign on it so you know later.
Connect a wire to one of the screws in the corner, this will be negative.

The above method is in use for the last three weeks, the four legs are perfect support for mounting inside a junction box or on a piece of wood.


Power and mobile operation 

Works with 9 to 15 volts.
Officially no over-voltage or wrong polarity protection. My experience is:
It seems indestructible: if the preamp receives 9V to 15V, connected properly, it will operate.
Seems to survive user errors:
- 12V car battery, connected the wrong way: amplifier survives.
- 12V car battery, short-circuited during operation, sparks everywhere: survives.
- Amplifier mounted on top of antenna, no enclosure nor protection, heavy rain: works.
- Rain on amplifier: all works fine.
A great advantage is that either inexpensive 9V batteries can be used for mobile operation, or directly powered by 12V car batteries; no converter needed.
Mount it inside an electrical junction box, power it with a 9V battery and you're ready to go.

Conclusion

After a good discone antenna this should be the next addition to any RTL-SDR setup.

6 comments:

  1. This comment has been removed by a blog administrator.

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  2. Great info! Your posts are really helpful.
    - Do you see any drawbacks in using this LNA ? Have you experienced any deterioration of the reception at any frequency ?
    - It is better to mount it directly(or as close as possible) to a roof antenna, correct ? So: Antenna-->LNA4ALL-->Coax cable-->SDR Receiver ?
    - Any idea about power consumption? How long would a fresh 9V battery be able to power it for ? Do we have a figure about the current it draws ?

    Many thanks in advance !

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  3. I'd love to buy "the" book. But - Amazon Kindle edition? No way! Is there another way?

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  4. why does everyone fear water and electronics? Here's the deal - IF something get wet ....UNLESS the water has caused corrosion OR a direct short of a component IE; when power is applied and a short occurs OR residual power in a cap is shorted across a circuit - dry it out and its gonna work. Motherboard dirty? Take it out - disconnect everything put it in the dishwasher (no dry cycle, no soap) - dry it THOROUGHLY. 3 days later you have a nice shiny clean MB - What do you think restoration companies use when your house catches fire? deionized water baths! No mystery chemicals...cheers.

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