Author Topic: Scannermaster LNA-AIR Pre-Amp?, Anybody tried one?  (Read 2890 times)

Offline uplink

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Scannermaster LNA-AIR Pre-Amp?, Anybody tried one?
« on: November 11, 2010, 09:44:41 PM »
Anybody tried the Scannermaster LNA-AIR pre-amplifier?  

http://www.scannermaster.com/LNA_AIR_Pre_Amplifier_p/24-531043.htm

Not much on the net or forums as far as far a reviews go.  Was it worth it?  Wondering if it's GaAs FET? What power supply and or injector did you use?  Thanks ahead of time!

:D
« Last Edit: November 11, 2010, 09:49:43 PM by uplink »



Offline dave

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Re: Scannermaster LNA-AIR Pre-Amp?, Anybody tried one?
« Reply #1 on: November 11, 2010, 09:48:22 PM »
Works fine.  This power injector works well:

http://www.scannermaster.com/PWR_I_Power_Injector_p/24-531289.htm

or you can build your own.

I believe it is a GaAsFET.  Don't find too many MOSFETs in use these days - GaAS is cheap now.


Offline uplink

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Re: Scannermaster LNA-AIR Pre-Amp?, Anybody tried one?
« Reply #2 on: November 11, 2010, 09:54:36 PM »
Thanks Dave!, haven't bought a preamp since building a repeater in the 80's,  :lol: Angle Linear GaAs was the "in" thing then.

 I Think I'll try one of these on my airband yagi just for fun.

 :-D

Offline heywood

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Re: Scannermaster LNA-AIR Pre-Amp?, Anybody tried one?
« Reply #3 on: June 13, 2017, 03:07:45 PM »
Sorry to resurrect a very old thread, but how did this work out? Did you get any perceptible improvement in sound quality?

I ask because I'm considering adding an inline LNA to my setup, which has an Arrow GP126, and I'm wondering if it's worth the trouble. Curious to hear about your experiences either way.

Thanks,

-HJ

Offline dave

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Re: Scannermaster LNA-AIR Pre-Amp?, Anybody tried one?
« Reply #4 on: June 13, 2017, 03:37:44 PM »
Whether a preamp is worth it for your situation is not an easy answer. Much of the time preamps are not worth the effort.

First, if you are using the preamp to overcome splitter loss caused by the use of a power splitter (to feed multiple receivers) then it is almost always worth it. Be careful to not use more than 2-3dB excess gain than you need in that application. Depending on the receiver, feeding it excess signal power may cause spurious response issues (intermod).

If you only have a single receiver, then the only application where a preamp makes much sense is to overcome the loss of excessively lossy coax cable. In that case you would want to remotely mount the preamp outside at the antenna. The LNA-AIR preamp has a model that can be powered through the coax cable - but it's not weatherproof - so you will have to mount it inside a weatherproof enclosure.

One other important thing - if you are externally noise limited, the preamp will likely only hurt your performance. If you open your radio's squelch and hear lots of buzzing noises or other intermittent type noises, you are probably noise limited. In cases like this it's better to spend time trying to eliminate the noise sources. That can be a difficult task, but there are many ways to attack it. Sometimes the easiest way is to relocate the antenna...or move it outside if it's inside now.

Give us some idea what pieces you are working with:

1) Type of antenna and placement
2) Type and length of coax cable
3) Type of receiver
4) Distance from airport

-Dave