Low-noise amplifier for Antennas

[xchgre]

Hi, my neighbor told me that LNA Low-noise amplifier can be used to increase the gain and keep noise low from RF signals.
Which apparently are famous in the world of ham radio.

https://en.wikipedia.org/wiki/Low-noise_amplifier
https://www.onesdr.com/2020/01/11/an-in ... fications/

I wonder what the effect would be if we install these devices to our antennas.

[Didneywhorl]

It'd be a cool experiment. Im curious to the cost. Usually this type of specialized equipment costs way more than the value it brings. I tend to see more value in higher quality antennas versus 'boosting' a signal from a cheap antenna. I'm often surprised with cool new tech though.

[xchgre]

It'd be a cool experiment. Im curious to the cost. Usually this type of specialized equipment costs way more than the value it brings. I tend to see more value in higher quality antennas versus 'boosting' a signal from a cheap antenna. I'm often surprised with cool new tech though.

Yeah, the lna are cheap, the SPF5189 US $ 4.38 in AliExpres

But I have no idea if is worth, lets see if someone throws more information

[terryjett]

I would stay away from such. Can be VERY disruptive to cellular RF equipment. A low noise amplifier such as you describe amplifies everything, including noise. Think of it as watering your flower garden with a fireman hose instead of a garden hose.

Too much and soon or later, you can expected to be tracked down by carrier engineering department.

I will come right out and say: very bad idea.

[terryjett]

Yeah, the lna are cheap, the SPF5189 US $ 4.38 in AliExpres

But I have no idea if is worth, lets see if someone throws more information

I have to ask why you used a link like t.ly/px that forwards to preferredby.me/su/esud and then reveals the product @ es.aliexpress.com/item/28.html ?

All this seems little fishy to me...

[Didneywhorl]

Looks like an affiliate link system, using a legit link shortener to hide the affiliate link

[Didneywhorl]

All references are generally in spanish, but that's exactly what it is. An affiliate link system that supports aliexpress.

[xchgre]

I have to ask why you used a link like t.ly/px that forwards to preferredby.me/su/esud and then reveals the product @ es.aliexpress.com/item/28.html ?

All this seems little fishy to me...

Sorry it's the habit of doing it. I have deleted the link.
Whenever I copy the links it self-affiliate
Thanks anyway for the information

[terryjett]

Sorry it's the habit of doing it. I have deleted the link.
Whenever I copy the links it self-affiliate
Thanks anyway for the information

I think it is perfectly fine to use affiliate links long as not over done. I have seen quite a few affiliate links over the years, but did not recognize that one:) I do not make any rules here, so just my personal opinion.

Now if someone comes here and provides no help / information, posts nothing but fake posts with affiliate links - totally different story. Personally I just add them to my ignore list.

[AntennaRaul]

An LNA is only for an RX system unless it's a very specialized one with an RF bypass. Your Tx will fry the LNA instantly.

[tetranz]

An LNA is only for an RX system unless it's a very specialized one with an RF bypass. Your Tx will fry the LNA instantly.

Very true. Even if it doesn't fry the amplifier, the system simply will no longer work well on transmit.

That said, the following is mostly moot but ...

Hi, my neighbor told me that LNA Low-noise amplifier can be used to increase the gain and keep noise low from RF signals.
Which apparently are famous in the world of ham radio.

The important thing thing it does is not so much "increase the gain", because you could do that more conveniently down at the receiver. A LNA or "masthead amplifer" will increase the gain in the place that gives you the most advantage. It increases the received signals before they suffer any loss in the cable. If loss in the cable significantly reduces the signal to noise ratio at the receiver then a LNA is a good way to solve that, if you can solve what happens for transmit.

Sort of related but I like the general idea of having active components close to the antenna. i.e., placing the modem near the antenna. It means that you only need to run ethernet and power to it rather the coax. Loss and length become mostly irrelevant then. Of course it brings practical considerations of waterproofing, temperature etc.

[AntennaRaul]

Correct. An amp for receive on a TV antenna is much better there than at the receiver side. At the antenna it amplifies a cleaner signal. For transceiver systems the equipment running a very short coaxial feed line and placed in an enclosure right on the mast is great. Just then run power and data to it. This makes a significant improvement to cellular modems. And it's great to broadcast the Wifi signal from up there too!

[terryjett]

An LNA is only for an RX system unless it's a very specialized one with an RF bypass. Your Tx will fry the LNA instantly.

Welcome back!

Guess you did not get the PM? Way back when you asked me for my address to send surplus to me:) Anyway, appreciated the offer.