Re: Receive Antenna & Impedance "Matching"
A core i5 refurb with a decent screen where we live is closer to $400 and then you start thinking it's 5400rpm snaildrive needs replacing with an SSD, and a new Pi4 is $60 but that's not the real story.
I've got two remote Pi running irrigation pump, watering etc which means driving relays via the Pi I/O pins. In the shack another one drives the FT-857D and an old FRG-9600 doing TTL CAT directly from the pins, the FRG-9600 works really well as Pi driven scanner. The FT-991 is connected via USB and my homebrew software controls every function and all memories and all prefs/param settings.
No Pi has a screen, mouse or keyboard, they are all headless running SSH for OS level work and have onboard node.js web servers for their user interfaces, all web-socket driven, updating multiple users from anywhere. One Pi in the shack streams full time audio from scanner and any other rig onto the LAN using multicast so I can listen anywhere. In the shack they are powered by linear 5V regulators connected to the 12V 1KW solar battery bank, so tiny footprint and useful. Coding/programming is also a big part of my hobby and a Pi makes a great development platform if you happen to be using the same programming language out in the wild, as I do.
I take my Pi3B to our rock-n-roll club when it's my turn to do the music, it runs (free) Volumio and has the entire club music collection on board, use it at home otherwise. Volumio is great for anyone wanting to carry a complete portable music system, it creates it's own local WiFi network (or joins one) allowing phones or tablets or computers to control it via web browser, has an optional app, supports web-sockets for multi-user. Handily it alternatively accepts audio streams via WiFi straight from any music on an iPhone or Android device or computer. Accepts USB music too. /end plug
Watch out for your data on those Iomegas! Very popular when they first came out but my two died prematurely from the dreaded click-of-death with no warning. I've still got their little blue power packs with the obligatory bent pins.
The continuing WSPR shootout between the FT-857 and FT-991 is interesting, the 857 is around 1dB better SNR on almost every spot after 12 hours with largest SNR difference for any single spot being only 2dB.
That tiny 1dB average advantage meant the 857 had 47 more spots which demonstrates just how important an extra 1dB SNR is, for WSPR anyway.
Over the last 12 months I've been using the same technique to slowly improve antennas and feedlines and that has been really meaningful, don't overlook the usefulness of WSPR if you are inclined to do some testing. Anyway I'll leave those two rigs running for a full 24 hours UTC then start switching radios.
My thought was to put the RSP2 up against the FT-857 for a day or two to get a known SNR relationship between them and then put the preselector in series with the RSP2 and fiddle.
After that I might try a shootout between the RSP2 and RSP1A...
If anyone wants to follow the current radio shootout, open http://wspr.vk7jj.com/ in two web browser windows simultaneously and configure them as illustrated below.
The FT-991 is VK7JJ and the FT-857D is VK7JJ2
The auto-search needs to be on (on both) to ensure they both get the same bunch of spots as new spots are uploaded every even two minutes. Make sure the VK7JJ band is set to 30m because 40m antenna testing is ongoing.