SteveBrown
Newbie
In preparation for installing a UHF TV antenna on my roof, I installed TV viewing software on a laptop computer so that ATSC TV broadcasts can be viewed by means of a USB tuner stick plugged into the computer. However, the viewing software can display only one channel at a time, and the signal strength indicator only displays six bars, not very good resolution. It occurred to me that even though SDR software is not designed to view television, it can display the carriers of several channels simultaneously, with very good resolution of amplitude. Toward that end, I ordered an RTL DVB-T USB stick to use with SDR# software. I expect that viewing the amplitudes of several channels at the same time, perhaps even the entire UHF band, I should be able to optimize the orientation of the antenna to receive the greatest number of channels.
I'm also interested in playing with SDR to monitor VHF police and aircraft communications, so I'll eventually mount a vertically polarized scanner antenna on top of the same mast. I have an RCA outdoor preamp with separate UHF and VHF inputs, so that should work nicely for UHF TV plus VHF communications. I wonder if there might be an issue with impedance matching, as scanners and antennas tend to have 50 ohm impedance, whereas TVs and antennas tend to have 75 ohm impedance. The output of the mast-mounted preamp is 75 ohms, so 75 ohm coax is the obvious choice there. I presume the input of DVB-T dongles is 75 ohms, but correct me if I'm wrong about that. On the inputs to the preamp, I may use 75 ohm cable from the TV antenna and 50 ohm cable from the scanner antenna, but I wonder if mismatch to the scanner antenna will be an issue.
I'm also interested in playing with SDR to monitor VHF police and aircraft communications, so I'll eventually mount a vertically polarized scanner antenna on top of the same mast. I have an RCA outdoor preamp with separate UHF and VHF inputs, so that should work nicely for UHF TV plus VHF communications. I wonder if there might be an issue with impedance matching, as scanners and antennas tend to have 50 ohm impedance, whereas TVs and antennas tend to have 75 ohm impedance. The output of the mast-mounted preamp is 75 ohms, so 75 ohm coax is the obvious choice there. I presume the input of DVB-T dongles is 75 ohms, but correct me if I'm wrong about that. On the inputs to the preamp, I may use 75 ohm cable from the TV antenna and 50 ohm cable from the scanner antenna, but I wonder if mismatch to the scanner antenna will be an issue.