After much time doing only microwaves activities, I listened the encourage words from Luis EA5DOM, to try to receive LF and MF . Luis is active in 136kHz and 477kHz in TRX and uses Opera, WSPR and have a SpectrumLab grabber.
The most common modes are OPERA32 (32 mins period), wspr15 ( 15 mins period) in 136kHz, and OPERA-8 (8 mins period) WSPR-2 (2 mins period) in 477kHz. The OPERA and WSPR uploads to Internet the receptions as spots and is possible check online the results and distance. This is feature is very nice to compare results with another stations.
I’m really surprised for the good results and for the nice signals that can be received in this low frequencies with a small antenna. I know that this band some times not are easy for the local QRM/QRN generated by switched power supplies, motors, etc.. but with not much effort is possible get some setup to receive this bands.
I encourage that you try to receive this bands. A good point to start is the 477kHz band. It can be received easy using a base HF transceiver and antenna.
Recently I build a circular polarization feedhorn to try to do EME in 1296 MHz. The hint was that it have very easy to build and cheap. I was looking some designs based in ual mode septum designs from N2UO and RA3AQ but they not are easy to build for me. My idea has been use fireplace pipe and a dielectric depolarizer.
To build the feehorn I have used fireplace inox pipe of 150mm and a galvanized reduction from 250 to 150mm. The dielectric depolarizer is a piece of Rogers Duriod 5880. To try to minimize the number of sma connectors, I used a small piece of Suhner .141 as a probe that will connect directly to the LNA saver switch.
In the TX port I used a standard N connector. I measured the RL in the lab, but have to measure the RL in the dish for this reason the bottom plate not is soldered yet, it is glued using metalic tape, until the RL is adjusted on the dish.