Jump to content

Microwave Dish Signal Range


n925tv

Recommended Posts

I was watching the Virgin Galactic SpaceJet crash today on the 1pm news on KTLA. Most of LA's news helicopters went up to get live footage from the crash scene, so that got me thinking. Mojave is 100 miles north of Los Angeles, what's the microwave signal range for the Helicopters? How far can they go before loosing signal to the station? Thanks!

Link to comment
Share on other sites

Most airborne microwave systems have a long distance range. One such system in manufactured by Troll Systems that has a 195 mile range at full power. But most likely the have multiple receive sites with directional antennas if the terrain is mountainous.

Link to comment
Share on other sites

I think ENG trucks typically max out at 50 miles mainly because of differences of terrain. Both live trucks and helicopters require line of sight but the advantage that helicopters have is their altitude. Helicopters fly above the hills, trees and buildings that may block a live truck whose masts generally max out at 50 feet.

 

One of the recommended tips that I read for live truck operators is to keep an extremely detailed map of where you can get a signal down to the parking spot. A one or two spot difference may change your ability to get a strong signal.

 

But now-a-days most stations use antenna pointers which automatically chooses the best receive site based on the GPS location and altitude to send a signal to the receiving antenna telling it which direction to point to so they will get the strongest signal. Consequently the send and receive antennas are constantly readjusting. For live trucks trucks it's much simpler where they are in one location but the equipment will still control the direction and tilt of dish on the truck and the receive site.

 

BTW, Nice handle, N925TV, I take it your a dedicated KTLA fan?

Link to comment
Share on other sites

Wow, thanks for all that info. Very detailed, and appreciated. I'm still learning all this stuff.

 

Yes, very dedicated KTLA fan, been watching since I was 4 yrs old! Hope to work in the helicopter one day (contracted by ACA), hence my handle. :)

Link to comment
Share on other sites

 

I was watching the Virgin Galactic SpaceJet crash today on the 1pm news on KTLA. Most of LA's news helicopters went up to get live footage from the crash scene, so that got me thinking. Mojave is 100 miles north of Los Angeles, what's the microwave signal range for the Helicopters? How far can they go before loosing signal to the station? Thanks!

 

 

Cool, thanks for the info! What about the Microwave dishes on the Live Trucks? Same distance?

 

 

The answer to all those questions is really "it depends". Terrain is perhaps the most important, followed by transmitter power, signal frequency, the size of the antennas involved... The further away you get, the harder it is for either end to lock on to the other (and there's not as much automation out there as you may think).

 

The key factors working in favor of the LA stations in this instance are that this happened due north of Mount Wilson and that it's practically flat between there and the crash site. The transmitters on Mount Wilson are something like 3,000 feet above "average terrain", which is about 2,000 feet higher than a lot of stations. You could go a ways away before the signal started breaking up.

 

Some stations had ENG trucks/portable kits capable of relaying a helicopter's signal back in the days of analog, but I think that isn't so common anymore. KDKA used to have trucks with two masts to relay signals around the hilly terrain of Western Pennsylvania. This picture from 2010 suggests they still might have trucks like that, at least until recently.

 

This article explains things very well: http://en.wikipedia.org/wiki/Microwave_transmission#Microwave_radio_relay

Link to comment
Share on other sites

Maybe a factor could be the infrastructure of microwave links/STLs/repeating links that could vary market by market? I remember seeing a video tour from WPVI's website years ago (from the old building) where their microwave receive room could pick up signals all around the market including places like Harrisburg. Obviously that would be microwaves.

Link to comment
Share on other sites

Maybe a factor could be the infrastructure of microwave links/STLs/repeating links that could vary market by market? I remember seeing a video tour from WPVI's website years ago (from the old building) where their microwave receive room could pick up signals all around the market including places like Harrisburg. Obviously that would be microwaves.

Yes, the microwave links do vary by market to market and station to station. It doesn't surprise me at all that a station like WPVI could afford to set up and maintain a microwave receive station in Harrisburg. I would imagine they take the receive site and fiber it back to the station.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using TVNewsTalk you agree to the Terms of Use and Privacy Policy.