Originally Posted by Jim in Seattle
Sorry to bump your older post but I thought you might like to know it's 76 miles from KVOS to me and my home-brew 15 bar cut-to-35 Yagi is about 218 feet lower
than your other QA Hill friend who is concerned about the horizon. Does this prove RF 'bends' over the horizon? It certainly works for meee!
Steve at KVOS (CE) told me I'd never
be able to receive them (wrong) and I doubt anyone here could have guessed I could also capture the Grays Harbor/LeBam translator for KBTC almost 90 miles distant and it is genuinely LP! Speaking of weak signals, I think I'll check analog 62 in Port Angles to see what's on tonight.
Hopefully the above brought a smile to your face! Like you, I don't like to lose.
Jim in Seattle
When they said it was right on the horizon, you have to take that with some lattitude. They never said how much it cleared it by. Microwave links are a different critter from TV, and I can't remember what frequency they were using.
Main thing is, when you get near a 100 miles, that's really pushing the limits of HD UHF. Add in elevation and it can be make or break it.
And for bragging rights, when I lived in Redondo, on the beach at elevation 20ft, I could get the old analog KVOS pretty good at 95 miles. It took three Blonder Tongue 60 db notch traps and an old Channelmaster 3617 (all 18ft of it) to trap out ch13 & 11. I also get HD KVOS here, two miles further, but 200ft higher, in the trees, with a 4221 and an old UHF preamp that was tweaked for it. It also takes a very good tuner.
From where you are, KVOS is still line of sight and above the horizon. What makes yours tough is all the powerful noise from the towers on the hill. Your yagi is helping a lot, too.
HD signals aren't really coming to you like a laser beam. They scatter more than you realize. Picture a car coming towards you at night, just over a hill. You can't see the headlights, but you see the glow. Not much there for you to see by, but it's light. When you get behind a hill, you can get some HD signals, just depends on many factors whether it will be enough to work with.
laurienicol is almost at sea level about 110 miles to QA Hill. Technically, it's possible, but there are some hills in the way only a few miles away. By the time signal gets there, it's very weak. That's what I found amazing.
So no, TV UHF RF doesn't really bend, but the scatter can sometimes be enough to work with. Yes, the lower the frequency, the more it can go over hills, again depending on various factors of type of modulation, power, etc.
Signals can also bounce off the troposphere, which is what we used in the military in ancient times. Took a lot of power and some big mo-fo antennas, but we could go around the world. It's technically possible to get TV signals that way, but it's far more likely they're getting atmospheric weather conditions that allow it to bounce along at much lower altitudes. Look up troposheric propagation for a better explanation. And as others have noted, reception that way is not very reliable.
I agree, not sure what the KVOS Steve person meant by his remarks, but you can't argue with good pictures!
As for your getting other areas, that's where good equipment and some persistence pays off. Well done.
The example of distant reception I like is that the satellites Directv and Dish use only transmit with about 100watts of power, 22,000 miles up. It takes some very sensitive antennas, preamps and tuners to make all that work, but it can be done. Back in the late 70's we had to sort through expensive transistors to get ones low enough in noise just to see the TV satellites, with 15ft dishes. Things have have obviously improved, far more than most people are aware of.
Yeah, I still smile when I get a win on a tough one. And I still find it amazing sometimes, like when I was a kid, that you can get all these stations out of the air with just a radio and some wire going out to the tree......
Geeze, ramblin again. Gotta get back to decaf.....