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[82.70.254.222]) by smtp.gmail.com with ESMTPSA id b5sm8836909wrb.42.2018.03.16.05.15.28 (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 16 Mar 2018 05:15:28 -0700 (PDT) Date: Fri, 16 Mar 2018 12:15:27 +0000 From: Chris Wilson X-Priority: 3 (Normal) Message-ID: <384425899.20180316121527@gmail.com> To: LineOne CC: dead.fets@gmail.com In-Reply-To: References: <772364530.20180316113613@gmail.com> MIME-Version: 1.0 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Andy, OK, thanks for that Andy. I can see one future snag though, if I use both "aerial" ports on the Red Pitaya and an antenna splitter so I can receive LF and MF at the same time, I will need two pre amps, one on each port, as putting a single one between aerial and input port of splitter will mean any BPF is AFTER the pre amp... Not a huge deal as I have two pre amps, but I am guessing that's what i will have to do? [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (dead.fets[at]gmail.com) 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 6ffbd2c9950b634d6cc91f9565b01a8b Subject: Re: LF: Pre amp *after* BPF?? Content-Type: text/plain; charset=utf-8 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=PRIORITY_NO_NAME autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by klubnl.pl id w2GCJ6pw010259 Hello Andy, OK, thanks for that Andy. I can see one future snag though, if I use both "aerial" ports on the Red Pitaya and an antenna splitter so I can receive LF and MF at the same time, I will need two pre amps, one on each port, as putting a single one between aerial and input port of splitter will mean any BPF is AFTER the pre amp... Not a huge deal as I have two pre amps, but I am guessing that's what i will have to do? Friday, March 16, 2018, 11:54:09 AM, you wrote: > After, definitely > Before is applicable to VHF and up where equipment noise figure > dominates sensitivity and a filter in the antenna side wold add loss and degrade overall NF > At HF and certainly LF, atmos noise dominates to noise figure is > unimportant.   That way you get the benefit of rejecting strong OOB > signals that may stress even the preamplifier > 'jnt -- Best regards, Chris mailto:dead.fets@gmail.com