Split-Split

Last year I built an Over-The-Air TV antenna system for my mother who wanted to cut the cable. Worked fairly well when I installed it, and I marked it up as the best over-designed antenna system I’ve ever installed.

Lately, she’s reported that some of her channels have disappeared. Been racking my brain to think of the cause. Figured it was the antenna being just below the roof line, and that I’d need to attach an extension pole, or that the lightning arrestor has failed, or wind/wildlife misaligned the UHF yagi.

Then it dawned on me tonight at the hardware store: I have a 4-way splitter in the system, but only 2 TVs. Each pair on a splitter reduces the input signal by 3.5dB, typically, and as this has 4 legs, the signal has an overall insertion loss of -7dB. If you consider each -3dB change is a halving of the signal, I’ve basically built a system where each of the 2 televisions is getting 25% of the antenna signal, even though the other 2 terminals (unterminated) are not in use.

WTF, mister.

I grabbed a 2-way splitter and I’ll try it soon. Hmph.

I feel like I should be ashamed that I didn’t think about insertion loss being directly proportional to the number of output ports on a splitter, but really, it’s all part of the learning.

Radio is hard.

Published by Shawn

He's just this guy, you know?

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