[Hackrf-dev] Amp On or Off

[Tom]

Unless I am reading it wrong but doesn't the MGA-81563 have an absolute max Pin of +13dbm?

-----Original Message-----
From: HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com] On Behalf Of Scott Davis
Sent: Thursday, 2 July 2015 1:15 PM
To: hackrf-dev at greatscottgadgets.com
Subject: Re: [Hackrf-dev] Amp On or Off

This hypersensitive behavior is a little odd for a device that is meant to be an experimental RF platform.  Is there possibly a more robust front-end component set that could be substituted for the existing one?

FWIW, I routinely transmit 3 to 5-watt signals (usually ~10-15 seconds duration) using resonant antennas within a meter or two of my HackRF, and the preamp still works perfectly.

-Scott

Sent from my iPad

> On Jul 1, 2015, at 7:13 PM, 王康 <scateu at gmail.com> wrote:
> 
> Actually, you can tune to a FM station nearby, observe the signal 
> strength with preamp switched on and off, using `osmocom_fft` or 
> `gqrx`.
> 
> If your signal peak become *higher* when preamp is *off*, then the 
> preamp is definitely blown.
> 
> I made some batches of HackRF a year ago, and found that preamp can be 
> easily damaged even before shipped.
> You may buy some preamp components, replace the broken one if needed.
> 
>> On Wed, Jul 1, 2015 at 11:02 PM, Daniel Bernhardt <daniel at dbernhardt.com> wrote:
>> 
>>> Now the amp is presumed blown it acts more like an attenuator, i.e. signals are weaker with it switched on.
>> Not regarding your specific case:
>> Is there a definitive way to determine if ones preamp is blown or not? For all we know it could be a faulty antenna setup or a cabling issue. Is the amp completely bypassed if turned off or just not amplifying? What are the symptomps of a "blown" amp? Does it short or are there signals coming through much weaker due to some cuppling effects?
>> Forgive my ignorance on the matter. Just beeing curious.
>> 
>> Daniel
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