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Originally Posted by ADTech
...scratches head.... I've tested numerous antennas with a VNA, but I've never tested "radiance".
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Yeah sorry, I meant to just say S11 measurement. It was interesting though looking at the analyzer plot that there was a narrow pole (maybe 6MHz BW) around 220Mhz. The system was however impedance mismatched (50/75 at load), but I don't think that would affect the locations of the poles themselves, just the amount of power transmitted to the load.
Quote:
Originally Posted by ADTech
The obvious thing is that the antenna you built is a UHF antenna (it's a copy of an old Radio Shack/Channel Master design) operating between 450 and 800 MHz. Channels 7-13 occupy 174-216 MHz. Antennas that are too small electrically do not resonate well and you usually suffer extreme return loss which, in an ATSC system, results in significant reflections in your cable and at the input to the tuner. Such reflections behave the same as short-delay multipath and, if excessive, can cause the tuner's function to fail.
Indoor reception of VHF is often complicated by:
1) Lower transmitter power which doesn't yield enough field strength to adequately penetrate construction materials.
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But isn't the governing factor here the apparent power at the load? In terms of raw dBm, the VHF signals are largely on-par with those in the UHF band for my geographical location.
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Originally Posted by ADTech
2) Localized sources of RFI from in-home electrical/electronics stuff, even the TV set itself, can readily wipe out VHF reception.
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Ahh yes, that would make sense.
Quote:
Originally Posted by ADTech
3) Effective VHF antennas require 2X-4X size increase over a comparable UHF antenna making them unwelcome in consumer's living space. Smaller VHF elements are therefore usually implemented which, combined with lower signal powers indoors, often causes erratic reception.
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Thanks for your response. I should also mention that I am not opposed to mounting outdoors, I just don't want to add additional hardware to the exterior if it can be avoided.