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Visited a radio observatory in New Mexico last month and kept noticing how many of their homemade dishes used old satellite TV parts
I saw at least 5 setups at the VLA visitor lot built from scrapped DirecTV LNBs and rusty pizza pans, but everyone online swears you need machined aluminum for a decent signal, so who's actually right about cheap hacks versus spending $200 on real gear?
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michael_green442mo ago
Hang on though, a rusty pizza pan isn't exactly the same as a precision reflector surface. You might be getting signal but are you getting the right signal without all that noise bleeding in?
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logan5252mo ago
Yeah I saw this video on YouTube from some ham radio guy testing different scrap metal reflectors and honestly the difference was way smaller than you'd think. He used a rusty old baking sheet and a brand new polished dish and the signal strength was almost identical for basic reception. I mean yeah if you're doing something super precise like EME or weak signal work then sure the rust might matter but for normal TV or radio picking up local stations it probably works fine. Read somewhere that the shape and focus matter way more than the surface being perfect. So idk I think people overstate how clean the reflector needs to be for everyday use.
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ryanm602mo ago
Matt's 2008 paper on antenna surface roughness actually showed that for frequencies under 3GHz, surface imperfections under 1/10th of a wavelength basically vanish in the signal. So a rusty pan at UHF frequencies around 600MHz is still way within that tolerance. The real issue nobody mentions is galvanic corrosion between the rusty reflector and your coax shield, that'll eat away your signal ground over time way worse than any surface pitting. I've seen rigs where the connector just fell apart after a year from that reaction. So yeah the signal might be fine now but check your connection points in six months.
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