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 Post subject: LNA gain
PostPosted: Tue Sep 05, 2017 3:51 pm 
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Joined: Thu Aug 18, 2016 9:05 pm
Posts: 12
Is there a way to control the LNA gain either manually or via software ? I see a signal named: SW_LNA coming from the PIC18F46 MCU, and I'm wondering if there is a command to toggle this signal, which I suspect, will control the LNA gain.

Thank you in advance,

73,
Rej. VE3MPV


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 Post subject: Re: LNA gain
PostPosted: Wed Sep 06, 2017 5:13 am 
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Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Hi Rej,

That signal is used to turn off the power to the LNA during TX. This avoids overload and reduces power. If you were to turn off the power to the LNA during RX you'd loose the 18-20 dB of gain that the SPF-5043Z LNA provides and you'd add the loss associated with the device in an off state which is at least another 15 dB. So the total hit would be about 35 dB.

But yes, it's under microprocessor control and I could make a command that turns it off.

73,
Jim WA2EUJ


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