Comm Tower Photos

prcguy · Jun 10, 2008

It doesn't matter how well the systems are engineered, the noise floor will still probably exceed 10,000k or more from broad band transmitter noise on these major sites and reception will be degraded.
prcguy

zz0468 said:
If these systems are engineered correctly, all the receivers on these antennas are completely oblivious to the fact that they're sitting next to a bunch of transmitters.

zz0468 · Jun 11, 2008

prcguy said:
It doesn't matter how well the systems are engineered, the noise floor will still probably exceed 10,000k or more from broad band transmitter noise on these major sites and reception will be degraded.
prcguy

Oh... yeah. Mt. Wilson is a horrid site to operate for that very reason. I was speaking in generic terms of a site similar to this:

http://www.dpdproductions.com/temp/towers1/pages/P0003634.html in KC0QNB's post.

On the other hand, I participate in several UHF amateur systems living on Mt. Wilson. The bulk of the broad band noise is far enough away from our inputs that the degradation is managable, and we don't really notice it. Blueridge, the other site in the OP's post, is quite busy too, but much easier to manage - it's not loaded with TV and full service FM broadcasters like Wilson is.

Our other little cross to bear here is Santiago. I think that's even worse than Mt. Wilson is, in terms of crud on the inputs.

But yeah, you're absolutely correct. If the noise floor is that high on your input, there's not much you can do.

WayneH · Jun 11, 2008

zz0468 said:
Nope. Point to point microwave radios typically run from 100 milliwatts to maybe 5 watts.

IN to the antenna more like. EIRP out is a hell of a lot more. See this license. 67dBm is a LOT of power. 44dBi gain will do that.

zz0468 · Jun 11, 2008

wayne_h said:
IN to the antenna more like. EIRP out is a hell of a lot more. See this license. 67dBm is a LOT of power. 44dBi gain will do that.

That power density still isn't enough to pop popcorn. I've run some pretty high power microwave radios, in the 30 watt class, and even that high, the heating effects are noticeable, but "lukewarm".

jb872033 · Jun 11, 2008

http://www.navycthistory.com/images2...IMG0950big.jpg <---------- sweet setup...what band is that for??

http://www.dpdproductions.com/temp/towers1/pages/P0003651.html<-------pretty odd shaped antenna...what are the advantages to a circularly polarized antenna such as this as compared to a regular antenna??

Interesting pics guys thanks for posting them and in advance for imput to the ? i have asked...not too familliar with antennas and am always lookin to learn more!

JB

Twister_2 · Jun 11, 2008

Is there a Noaa weather radio tower there?...or antenna?

DPD1 · Jun 11, 2008

Twister_2 said:
Is there a Noaa weather radio tower there?...or antenna?

No, the NOAA transmitter for the area is on a different hill.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist

WayneH · Jun 11, 2008

zz0468 said:
That power density still isn't enough to pop popcorn. I've run some pretty high power microwave radios, in the 30 watt class, and even that high, the heating effects are noticeable, but "lukewarm".

Exactly, won't pop popcorn but any organic body like a person would begin to have internal effects pretty quickly. Internal bleeding isn't fun. Boiling testes isn't either.

Even with cell site antennas what I've been told is to not stand for more than 6 minutes in front of one.

af5rn · Jun 11, 2008

I was fascinated by a "commo hill" at Camp Victory in Baghdad awhile back, so I snapped a few pictures that some might find interesting.

http://img2.freeimagehosting.net/uploads/378ab817fe.jpg

http://img2.freeimagehosting.net/uploads/5707a8dff9.jpg

http://img2.freeimagehosting.net/uploads/0884017763.jpg

http://img2.freeimagehosting.net/image.php?0bb9a964b1.jpg

All those X-shaped antennae on the short, guyed masts are for HF. Just about any building with an HF radio in it has one of those on it.

In photo # 2, at the far left edge of the photo, as well as on the right, just before that freestanding tower, are tan squares that are rotating radar antennae which (hopefully) detect launched rockets and mortars, giving us a few seconds warning to take cover, as well as helping to pinpoint the launch locations for retaliation.

WayneH · Jun 11, 2008

DPD1 · Jun 11, 2008

wayne_h said:
The above site was once linked to the site below on Mt Vaca by the Navy.
http://i241.photobucket.com/albums/ff81/Tricari/Comm_Sites/Navy_FAA_Mount_Vaca002.jpg

Wonder if that was cold war era, because that sure has some major survivability.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist

poltergeisty · Jun 15, 2008

DPD1 said:
Wonder if that was cold war era, because that sure has some major survivability.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist

Even after the EMP? :lol:

poltergeisty · Jun 15, 2008

Best I could find.

802.11n:lol:

KC0QNB · Jun 15, 2008

AF5RN, can't load your pics, wondering if the server is down
Here is a couple #1 a navaid of some sort, they tried to hide it behind a bill board on I 80,
#2 KRVN am transmitter site
we don't have real any impressive sites around here that I have found...yet, but I am always looking.

nd5y · Jun 15, 2008

KC0QNB said:
#1 a navaid of some sort, they tried to hide it behind a bill board on I 80,

The orange antenna on the left is a a 75 MHz marker beacon corner reflector antenna and the vertical with the capacitance hat on top on the right is a NDB antenna.

KC0QNB · Jun 15, 2008

Thanks Tom I didn't know that NDB antennas came in that design, all I have ever seen is the "T" style, well with one exception, there is one I ran across that looks like a classic sloper type only pictures I have of it were taken on a bad photography day, it has at least 8 elements going in all directions radiating from the top of the mast to about 10 feet above the ground, it was fed from the bottom of the mast, about three feet above the ground.

DPD1 · Jun 15, 2008

poltergeisty said:
Even after the EMP? :lol:

Probably not, but I'm sure that didn't stop them from trying. After all, they thought school kids could survive getting under desks.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist

dropkick · Jun 22, 2008

DPD1 said:
Wonder if that was cold war era, because that sure has some major survivability.

Dave
www.DPDProductions.com
Antennas & Accessories for the RF Professional & Radio Hobbyist

Google & look for pics of Strawberry Peak in southern california... http://www.thecentraloffice.com/Strawberry/Strawberry Peak.htm

Supposedly built to withstand a nuke blast over the valley below. Even some of the old microwave horns are supposedly somehow "hardened".

af5rn · Jun 22, 2008

KC0QNB said:
AF5RN, can't load your pics, wondering if the server is down

Ooops! I missed this when you posted it. The server must indeed have been down. The photos show up fine now. The server seems to go down at that image host site quite a bit, but it's less hassle than photobucket, so I stick with it. Sorry for the inconvenience.

I always keep my eye out for cool commo stuff to shoot in Iraq, but there is less of it than you would expect. And in my job, I don't have much to do with commo, except for the two HTs I carry on my belt all day, lol.

Probably the coolest thing is the one or two huge blimps that are tethered thousands of feet over Camp Liberty and Camp Victory all day, every day. Not sure what all is in them, but it includes an extensive radio and repeater network, as well as radar and visual surveillance equipment. I'd sure like to get a tour of them when they are on the ground someday!

KC0QNB · Jun 22, 2008

server down again or at least real slow, will try later FYI I use photobucket learned to accept the hassles.

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