My homebrewed PA0FRI Active Antenna is working well from a very physically constrained location.
3D render:
Schematic:
Results:
The antenna is connected to a RSP1 Clone SDR which is running custom FT8-band-hopping software. I am using a SOLID 4-Way 5-2400 MHz RF splitter to connect multiple SDRs to the same active antenna. NB: Plug-in 75-ohms dummy loads (terminators) on the unused ports of the RF splitter - MX-282 / MX-280 75-ohms dummy loads work fine.
Time to build: Less than 45 minutes for the PCB. The mechanical aspects (loop construction and boxing) can take a while.
My live reception results from this antenna can be viewed at the following URL(s):
Testing Update: An 10m EFHW antenna installed in the same 'surrounded balcony' location receives less than half-the-countries as compared to the PA0FRI active antenna.
Magic might not exist for grownups but the reception results of this Active Antenna from a very limited physical location are nothing short of magical!
The files for this project are published here for personal (non-commercial) usage.
Special shout-out goes to Ismo (OH2FTG) and Gajendra Kumar Sir for their guidance on these topics - thank you!
Notes:
The first two decodes in the following screenshot are from a "turned off" active antenna. The last two decodes are from the same active antenna when turned on.
References:
- Simple active receive loop antenna - for physical construction aspects