Long-wire performance on different ports, bands
Posted: Sun Sep 03, 2017 4:38 pm
I've been experimenting with my new SDRplay RSP2 with SDRUno, using for now as antenna a 40-foot (12m) long-wire with a plain-wire lead-in and a ground connection via a ground rod.
On HF, with the antenna and ground attached to the RSP2's Hi Z antenna port, performance seems excellent in AM, CW and LSB modes. Performance also seems fine on VHF for FM signals such as NOAA Weather and FRS with the antenna and ground attached to the RSP2's antenna port A.
On the MW broadcast band, with the antenna and ground connected to the Hi Z port as for HF, the noise floor seems high and signals are hard to detect. If I detach the antenna, however, and leave only the ground wire connected to the gnd connector on the Hi Z port, the noise floor drops and signals of various stations appear very strongly. I assume that the SDRplay's front end had been getting overloaded, and the ground wire alone provides all the antenna that is necessary?
In the commercial FM broadcast band, with antenna and ground connected to Port A, I again see high noise floor and poor signals. However, if I leave the antenna and ground attached to Port A and use SDRUno's console to select antenna Port B (to which nothing is attached), the noise floor drops and the signals are very strong, with excellent stereo. I assume that again this is a situation where the SDRplay was getting overloaded. Are there internal connections between antenna ports A and B that would allow the scenario described above to occur?
In any event, I plan to continue experimenting with some different antenna designs including an active mini-whip, baluns, etc.
On HF, with the antenna and ground attached to the RSP2's Hi Z antenna port, performance seems excellent in AM, CW and LSB modes. Performance also seems fine on VHF for FM signals such as NOAA Weather and FRS with the antenna and ground attached to the RSP2's antenna port A.
On the MW broadcast band, with the antenna and ground connected to the Hi Z port as for HF, the noise floor seems high and signals are hard to detect. If I detach the antenna, however, and leave only the ground wire connected to the gnd connector on the Hi Z port, the noise floor drops and signals of various stations appear very strongly. I assume that the SDRplay's front end had been getting overloaded, and the ground wire alone provides all the antenna that is necessary?
In the commercial FM broadcast band, with antenna and ground connected to Port A, I again see high noise floor and poor signals. However, if I leave the antenna and ground attached to Port A and use SDRUno's console to select antenna Port B (to which nothing is attached), the noise floor drops and the signals are very strong, with excellent stereo. I assume that again this is a situation where the SDRplay was getting overloaded. Are there internal connections between antenna ports A and B that would allow the scenario described above to occur?
In any event, I plan to continue experimenting with some different antenna designs including an active mini-whip, baluns, etc.