[amsat-bb] 70cm LNA

[Leffke, Zachary]

Minicircuits sells 'connectorized' filters (As opposed to just the SMT versions of things).  Depending on the requirements for the filtering they might meet your needs, but are not rated for high TX power.  As an example: their SBP-140 roughly comes in around 130-150 MHz for the 3dB passband, with a minimum insertion loss at 1.83 dB (at 140 MHz).  It is rated for .5W power, and costs around $50.  See (https://www.minicircuits.com/pdfs/SBP-140+.pdf) for more details.  They also have UHF variants.  They also have LPF and HPF variations depending on what you need.  My experience with these is that they are decent, but clearly not quite optimized for the Amateur Radio bands.....so sometimes you have to hunt around a bit to find something acceptable.

-Zach, KJ4QLP
-- 
Research Associate
Aerospace & Ocean Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305


-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Kevin Elliott via AMSAT-BB
Sent: Wednesday, August 12, 2020 3:40 PM
To: Zach Metzinger <zmetzing at pobox.com>
Cc: amsat-bb at amsat.org
Subject: Re: [amsat-bb] 70cm LNA

Yes now just to find filters for 2m/70cm out of the box ready :) Thanks!

> On Aug 12, 2020, at 12:38 PM, Zach Metzinger via AMSAT-BB <amsat-bb at amsat.org> wrote:
> 
> On 08/12/20 14:26, Kevin Elliott wrote:
>> Not wanting to use this with a transceiver, mostly just for my 70cm QFH with SDR for satnogs. Aware of any other 70cm and 2m LNAs that perform well for receive-only?
> 
> Hello Kevin,
> 
> I've heard good things about LNA4ALL (https://lna4all.blogspot.com/), which has a high IIP3 and low NF.
> 
> The +33dBm IIP3 would help with overload issues on the LNA itself, but the high gain (+23dB) would then overload your SDR/rig with those, now amplified, high-power out-of-band signals.
> 
> If you added an appropriate filter, such as the one I used, to the output, then you'd have a good solution.
> 
> --- Zach
> N0ZGO
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