At last an accurate way to find where the transmission towers are with distance, compass heading etc!!

Forums › Freeview (DVB-T/DVB-S) › At last an accurate way to find where the transmission towers are with distance, compass heading etc!!

NZRobin

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Master Geek

Topic # 95332 31-Dec-2011 03:06

I've been reading this site

http://www.aerialsandtv.com/testimonials.html#UsingGoogleToLineUpAnAerial

Google Earth and it's ruler. Distance, compass heading, elevation.

Now with my compass I know in which direction to point my aerial. I can even see just how much of an obstruction there is along the route with elevation. Still may have to do something about the trees though!

I thought I was pointing to PineHill, I wasn't! But by getting in close on Google Earth and running a line from PineHill back to my house I now know where to place my aerial to have the best chance to 'see around' the tall metal roofed house next door, same for Waiatarua. Brilliant!

This is going to be interesting!

NZRobin

161 posts

Master Geek

Reply # 563121 31-Dec-2011 03:18

By the way if anyone still doesn't know where the Pinehill transmission tower is, it's behind the reservoir at 192 Browns Bay Road Murrays Bay Auckland

sbiddle

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Biddle Corp

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Reply # 563130 31-Dec-2011 08:07

Radio signals can bounce off obstructions, so aiming directly at a transmitter if there is no line of sight may not necessarily deliver the best results. DVB-T is OFDM based and has no return path so reflections may actually offer a better signal that aiming the aerial directly at the NLOS transmitter. The only way to really tell though is to measure the signal strength to check.

NZRobin

161 posts

Master Geek

Reply # 563207 31-Dec-2011 12:51

Agreed. In my case I can not see the transmitters and was using my best guess to position the aerial based on which direction I thought the transmitter was and trying to get the best signal lock from there. In fact I had chosen probably the worst position to start. At least this way I at least know where they actualy are and can work from there.

By the way, if you do try to find the transmitters true direction this way using a compass don't forget to allow for magnetic norths declination. That is the difference between true north as given on google and magnetic north which in Auckland is 20 degrees. Or if you have a GPS or even your phone if it can pick up GPS and the right app then that can show true north.

Behodar

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Reply # 563219 31-Dec-2011 13:19

sbiddle: Radio signals can bounce off obstructions, so aiming directly at a transmitter if there is no line of sight may not necessarily deliver the best results. DVB-T is OFDM based and has no return path so reflections may actually offer a better signal that aiming the aerial directly at the NLOS transmitter. The only way to really tell though is to measure the signal strength to check.

In my case there's a top of a hill in the way, and it's actually better for me to point at a nearby house (higher up) and bounce the signal off the wall! I haven't had any issues since doing that :P

NZRobin

161 posts

Master Geek

Reply # 563375 31-Dec-2011 23:56

Behodar: In my case there's a top of a hill in the way, and it's actually better for me to point at a nearby house (higher up) and bounce the signal off the wall! I haven't had any issues since doing that :P

Better hope they don't add an extension then

Well I've repositioned my aerial to face waiatarua which of course is a much stronger signal than pinehill. So even though there is an obstruction of a house and a few trees across the road it's not enough to break up the signal. Signal strength in the high eighties on all channels but I don't know the arguably more important signal quality. But at least the picture is no longer breaking up. Of course the true test will be when it rains! So far though I'm pleased!