Hello LF'ers, Been Googling and see a mixed response to should a receive pre-amp go before or after a BPF. I have mine before the pre-amp, does the panel concur with this being correct? Thanks! Aeria
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, a
I say BPF first, then preamp (at least for LF/MF work). Strong out of band signals can cause all sorts of problems. Best to filter them before amplifying. I believe the small amount of loss in a good
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
Keep in mind that you only need a pre amp if the "antenna noise" is below the receiver noise. Most receivers have reduced sensitivity at LF / MF, but the noiselevels at these frequencies is high comp
Rik Agree ... except one should ideally switch between a 50 ohm load and the antenna when running the test. Jay W1VD -- Original Message -- From: Rik Strobbe <[email protected]> Reply-To: <rsgb
I would go along with Rik in principle, but beware of high static levels giving a misleading high figure of "antenna noise". This test only works on low static days. I would, in any case, suggest a "
Hi Mike I would agree with that. When I started trying to record stations in the pre-waterfall period (DCF, SXV, CFH etc near 136 I had a thick band on the plot around 8 to 10dB wide. I experimented
