Amplifiers mobile scanning

[bobsav21]

Check out this one
1-500MHz AD8367 RF Broadband Signal Amplifier Module 45dB linear Variable Gain | eBay

It got a variable attenuation built in. No need for variable voltage.
What do you think

 

[JamesO]

You do not what that Amplifier.

500 MHz max frequency, no noise figure specs, too high a gain amplifier.

You should buy the Amp I linked there are reasons I suggest it.

 

[bobsav21]

Yeah but UHF is all I need for this setup and I can crank the attenuation up and down with a pot on the board. Noise will have to be determined in actual field usage.
It cheap what do I have to loose.

 

[JamesO]

Even if UHF is all you think you need, this is not a good option.

You asked a question, you received a good solution, but chose not to listen.

I would not recommend or use this for many reasons. My guess is you do not understand things like Noise Figure, Total Gain and Intermod performance. We do not expect you to fully understand these things, that's why we are here to offer our experience and expertise.

If you want to use this, your choice, but the performance will not be very good.

Sorry I have to be blunt and call it as I see it.

The nominal Noise Figure of this Amplifier you are considering is around 7 dB give or take depending on the frequency and depending on how the part is integrated into the circuit board, the Noise Figure will likely just increase. This is a HORRIBLE Noise Figure, this is NOT a first state amplifier, it will likely be far worse than your set up without an Amplifier.

Here is the link for the Amplifier chip that is used - http://www.analog.com/media/en/technical-documentation/data-sheets/AD8367.pdf

 

[bobsav21]

Ok well the link you sent doesnt show any " specs" the ad sounds just like all the others on e-bay. Maybe I missed something along the way, if you have access to the " specs" please pass them along. I am listening but talk is cheap and facts and figures help sort out the BS from the " Take it from me " I know best.
Most of this imported electronic crap is made by the same manufactures then the seller tweeks his ad to make his product seem better that the others, but in reality a lot of it is the same product with different hype.
Bob

 

[zz0468]

The funny thing is people are quick to shoot all of this down without ever trying it.

What makes you think we've never tried it? Perhaps some of our cautionary tales are from direct experience.

And as for reducing the operating voltage, have you ever seen a preamp using a GAASFET that had an integral bias supply? What happens if the bias supply fails while positive voltage is still present on a GAASFET? How low can you go before the bias supply drops out?

We're not advocating not ever using a preamp, we're just pointing out that it can most certainly come with other issues needing to be resolved.

The rest of your post is completely irrelevant to the thread.

 

[zz0468]

I'm sure your right and the Bill would also be spectacular....$$$$$$$

I'm a poor retired Government employee just eating beans from a can...

Yeah, this is where you have to shop carefully. A public safety grade radio can be had for $20. The programming software can be found for free. The interface box and cable, maybe $30-40. But then you have a bit of a project. It can be a pain, but you can end up with a mobile setup than can hear the proverbial gnat fart at 50 miles.

 

[bobsav21]

"public safety grade radio can be had for $20" boy if you could point me towards that I'd buy 6 ...

Bob

 

[zz0468]

"public safety grade radio can be had for $20" boy if you could point me towards that I'd buy 6 ..

Shop on eBay for Motorola spectras and maxtracs.

 

[GMB951]

I ordered a Broadband low noise amp that came from China very small cable connections do anyone know what type cable this is very small and are their any type adapter they would fit very small will not fit BCD 996P2 antenna connection which are BNC