antennas

[claus]

so as a euro guy my experience with antennas is very limited.
so found this big one ,but dont know anything about it.(its seems to be grounded ,sending MW )

my question to you guys .whats a good way to know details about it .how do you guys do it when jumping a new A.
any info ,

thanks claus

[Faber]

most places they have a sign near the A,search on google on that(name)and you will probaly get some more info,sorry my english is too poor to tell what to look out for but im sure someone else will tell in the correct way..

[skybirdie]

Yo Claus!
Dropped you a message...

[Nick_D]

There are several ways to garner intel on Antenna towers . . .

My favorite is the sneaky way: If this is a commercial broadcast tower call the station on the phone and ask to speak to someone in advertising. Tell them you are the marketing director for the XYZ Company and are exploring the idea of purchasing some adverts on their station. Usually the salesman will be so anxious to get your account he’ll spill all.

While he may not understand what he’s talking about he’ll have some kind of script and the numbers should be right. Ask about coverage area and you'll probably get the signal strength and how far it reaches, and if it's AM or FM. (If the tower itself and the guy wires are insulated, it's probably AM). In general, the higher the signal strength and further that signal goes, the hotter the tower. The hotter the tower the less time you want to spend on, or even around, it. Generally, I’d say forget AM towers as you are really getting dosed by massive amounts of electro magnetic radiation while on them and you can electrocute yourself if touching one while being grounded.

You can get information about the exact altitude of the tower from the maps that pilots use. These will state both MSL and AGL so don’t mix them up! Here in the states they are called sectional maps and are available at pilot shops and small airports. I’m not sure what they are called, or even if they are available to the public, in Europe.

Also here in the states the FCC licenses all broadcasters and those licenses are available for inspection by the public so you can check to see if your country does something similar. The license will state signal strength, etc.

Two cautions: With current concerns about terrorism be careful how you dig for information as there are now more eyes watching these kinds of requests. And more of these towers are alarmed nowadays. Also, be careful around any kind of broadcast tower in general as you are up against electricity, and that’s like being in a knife fight with the Invisible Man . . .

Nick :-)
BASE 194

[Faber]

same oppinion on flight maps here(DK) besides they only show objects higher than 300ft,the alti on thouse cards i found is ONLY MSL,you will have to messure the object to be sure of the alti from exit to impact.

[imported_Mac]

You can buy sectionals here in the UK and most pilot suppliers also supply European maps. Or just ask the Pilot at your DZ if you can buy some from him.

Also there are many resources on the net for antennas. I have found incredibly detailed information on the web - Also as Nick says, call the company up and tell them some “mistruths” about your interests in their hardware – I have done this and found the technical director very open and helpful in helping me

You maybe surprised at the amount of large pointy things you have around you and the amount of information available to you…..

[jason]

>Generally, I’d say forget AM towers as you are really getting
>dosed by massive amounts of electro magnetic radiation
>while on them and you can electrocute yourself if touching
>one while being grounded.

I was intrigued enough by the first part of this statement to do a little research, and found two things. First off, Industry Canada has a site:

http://strategis.ic.gc.ca/epic/inter.../gg00026e.html

that includes a LOAD of information on Canadian (and a few American) broadcast antennas. Perhaps our friends to the south have a similar resource... And second, from their database, I've assembled the attached graph. On the left of the graph (low frequency) are AM stations. FM is the high-frequency peak. Power for AM broadcasters is significantly (two to three times) lower.

That said, RF radiation is the least of your worries on most towers, even when they're hot -- at least, the FCC seems to see them as pretty benign to workers, and that carries a lot of weight in my opinion. As you note, electrocution is a BIG concern on AM antennas. Unless you're desperate for altitude (and I've never been that desperate), you should think twice about getting into the ring with one of these things.

Edit: I should note that the antenna heights in the above database seem questionable in some cases, and reliable in others. A good secondary source, but perhaps not a primary for heights.