Obstruction on map, where it exactly?

[pilotod]

Obstruction on map, where is it exactly?

I was wondering about antennas that I see on my sectional. Since the antenna drawing takes up some space, where should I expect the base of the antenna to be...at the bottom of the drawing? There are some antennas near my airport and I see them on the map but have never figured out exactly where I draw my course to avoid them. And for that matter, the tops of things.....are they right at the top of the pointy spot of the mountain? Suggestions?

 

[JeffDG]

Well, the detailed "Digital Obstruction File" with the lat/long and the heights of all the obstructions on the charts is available:

https://nfdc.faa.gov/tod/public/TOD_DOF.html

 

[Let'sgoflying!]

I think its the dot at the base of the tower. Would I rely on its accuracy? No. Try to fly over them as well as avoiding them laterally.
http://flighttraining.aopa.org/pdfs/VFR_Chart_Symbols.pdf

 

[pilotod]

Ok, I can figure out all the lat/longs....but there's probably an easier answer....like all the pictures lat/long positions are at the base.

 

[Clark1961]

Ok, I can figure out all the lat/longs....but there's probably an easier answer....like all the pictures lat/long positions are at the base.

Doesn't matter much to me. I figure the guy wires extend out at least 1/2 the tower height. Can't see the wires so best to avoid the area by at least the tower height. That puts me well outside the area and don't need to ask where the base is exactly. I don't mind missing towers by a mile or more (okay, 1,000 ft over the top is okay too).

 

[pilotod]

Ok....I looked up the annoying towers that are over 1000 AGL near KEIK and found them in that file you linked to. It looks like the base (probably the dot(s) are the location of the obstructions. But I couldn't find that verbage in the other poster's response that linked to the chart symbols on the aopa site. But that site helps too.

Thanks all.

Well, the detailed "Digital Obstruction File" with the lat/long and the heights of all the obstructions on the charts is available:

https://nfdc.faa.gov/tod/public/TOD_DOF.html

 

[poadeleted20]

I think its the dot at the base of the tower.

That -- more or less, within the accuracy of things like that.

Would I rely on its accuracy? No. Try to fly over them as well as avoiding them laterally.

Yup. And mind those guy wires, 'cause you may not see them until it's too late. Just to be safe, figure avoiding laterally by the AGL height of the tower.

 

[denverpilot]

Ok....I looked up the annoying towers that are over 1000 AGL near KEIK and found them in that file you linked to. It looks like the base (probably the dot(s) are the location of the obstructions. But I couldn't find that verbage in the other poster's response that linked to the chart symbols on the aopa site. But that site helps too.

Thanks all.

If you can't find the towers near KEIK with a Mark 1 Eyeball, either the high-intensity white strobes have failed, or you've got some kind of special issuance for eyesight.

Those NOAA owned beasts are huge. They're also guyed as someone else pointed out, and the guys extend quite a way out, so give them a wide berth.

They're in an inconvenient location for north-south transiting aircraft along I-25 but they've been there a looooong time.

 

[murphey]

Doesn't matter much to me. I figure the guy wires extend out at least 1/2 the tower height. Can't see the wires so best to avoid the area by at least the tower height. That puts me well outside the area and don't need to ask where the base is exactly. I don't mind missing towers by a mile or more (okay, 1,000 ft over the top is okay too).

Of course that 1995 ft AGL tower east of Denver is always fun to try and miss. In the 5? 6? years it's been up, there's a non-stop NOTAM on some of the tower lights being out.

 

[murphey]

Re: Obstruction on map, where is it exactly?

I was wondering about antennas that I see on my sectional. Since the antenna drawing takes up some space, where should I expect the base of the antenna to be...at the bottom of the drawing? There are some antennas near my airport and I see them on the map but have never figured out exactly where I draw my course to avoid them. And for that matter, the tops of things.....are they right at the top of the pointy spot of the mountain? Suggestions?

If you're flight planning based on the cartoon on the sectional, or even the terminal, you really need to re-think your planning. The cartoon is a warning that the area has a major obstruction and you should avoid it by a substantial margin, and not assume anything about the physical structure in relation to the cartoon.

 

[Capt. Geoffrey Thorpe]

The tower seems to be within 1/2 a mile or so from the base of the symbol based on flipping back and forth from satellite and VFR chart views on the soon to be defunct runwayfinder.com

 

[denverpilot]

Of course that 1995 ft AGL tower east of Denver is always fun to try and miss. In the 5? 6? years it's been up, there's a non-stop NOTAM on some of the tower lights being out.

That thing's a monster for around here. The sites I work on rarely go above 100' since they're perched on big cumulogranite structures made by Mother Nature.

I don't like climbing the ones that sway in the wind. All of them do, to some extent, but some more than others.

Eerie when you're clipped on and reaching for an antenna mount out on a cross-arm, or worse, sitting on the cross-arm wrestling with a socket wrench or big wrench trying to get a corroded bolt loose.

If you're doing it right, you're clipped on with a full body harness and a bungee-type lanyard to the D-ring on your back, so if you do drop, you won't be dead of drop-shock to the inner legs and groin a few hours later if you have to hang a while for your buddies to rig up a way to reel you in. But it's still totally unnerving the first few times you do it.

Everybody always says "Don't look down" but that's never the part that bothers me. It's the once in a while slip of a foot or hand and the adrenaline shot as you re-grab your handhold or move the weight to your solid foot, that gets me. I'll have "falling dreams" for two nights after a day on the tower.

The worst day so far was either the day it started spitting rain and made the tower so slippery you thought you'd lose your footing on every rung on the way down, or the 50 MPH wind day in the face while sitting on a cross-arm atop Cheyenne Mountain trying to point a UHF Yagi at Conifer Mountain. Blew my hard-hat off. Ripped it right off, even with the chin strap tightened down and the head basket ratchet cranked tight enough it was giving me a headache.

I think my ground crew said something about finding it in Kansas sometime later that afternoon. It took off into the non-cleared brush and grass 50' from the base of the tower.

The ground crew never even heard my "Headache!" yell. Didn't matter, it blew way past them. The handheld radio in my tool bag was also utterly worthless that day. Couldn't hear it over the wind.

You can keep those 1000'+ monsters. I don't ever want to go up one of those.

 

[TMetzinger]

That -- more or less, within the accuracy of things like that.
Yup. And mind those guy wires, 'cause you may not see them until it's too late. Just to be safe, figure avoiding laterally by the AGL height of the tower.

At least, and unless you're practicing Nap-Of-Earth flying for SAR/EMS purposes, it's easy enough to miss them by a mile or so laterally or just be well above them.

Remember, particularly in singles, altitude=options.

 

[Teller1900]

That thing's a monster for around here. The sites I work on rarely go above 100' since they're perched on big cumulogranite structures made by Mother Nature.

I don't like climbing the ones that sway in the wind. All of them do, to some extent, but some more than others.

Eerie when you're clipped on and reaching for an antenna mount out on a cross-arm, or worse, sitting on the cross-arm wrestling with a socket wrench or big wrench trying to get a corroded bolt loose.

If you're doing it right, you're clipped on with a full body harness and a bungee-type lanyard to the D-ring on your back, so if you do drop, you won't be dead of drop-shock to the inner legs and groin a few hours later if you have to hang a while for your buddies to rig up a way to reel you in. But it's still totally unnerving the first few times you do it.

Everybody always says "Don't look down" but that's never the part that bothers me. It's the once in a while slip of a foot or hand and the adrenaline shot as you re-grab your handhold or move the weight to your solid foot, that gets me. I'll have "falling dreams" for two nights after a day on the tower.

The worst day so far was either the day it started spitting rain and made the tower so slippery you thought you'd lose your footing on every rung on the way down, or the 50 MPH wind day in the face while sitting on a cross-arm atop Cheyenne Mountain trying to point a UHF Yagi at Conifer Mountain. Blew my hard-hat off. Ripped it right off, even with the chin strap tightened down and the head basket ratchet cranked tight enough it was giving me a headache.

I think my ground crew said something about finding it in Kansas sometime later that afternoon. It took off into the non-cleared brush and grass 50' from the base of the tower.

The ground crew never even heard my "Headache!" yell. Didn't matter, it blew way past them. The handheld radio in my tool bag was also utterly worthless that day. Couldn't hear it over the wind.

You can keep those 1000'+ monsters. I don't ever want to go up one of those.

Dude, f-that! I didn't know that's what you do. I get shaky enough climbing on top of the wing to put oil in the engines. 100 feet is too high...1000+ is just not an option! Hell, standing next to the 500 footer outside my dad's office is enough for me.

To the OP: as everyone else has said, if you're flying close enough that it matters - you're doing it wrong.

On the other hand, if you hit the guy-wires, you can pretend like your plane has blasters (à la Star Wars).

 

[denverpilot]

Dude, f-that! I didn't know that's what you do. I get shaky enough climbing on top of the wing to put oil in the engines. 100 feet is too high...1000+ is just not an option! Hell, standing next to the 500 footer outside my dad's office is enough for me.

Nah, not for a living. I got into doing it 'cause few folks will go work on ham radio repeaters on mountain tops more than once. The novelty of "going to the site" wears off, but the maintenance continues.

Then I was dumb enough to get into VHF+ contesting. And you gotta put up a lot of metal into the air to make that work. You join a group, they point you at their safety conscious guy who hands you a harness and says, "We'll see how long it takes you to figure out how to get that on. Then we'll go hang the 6-meter Yagi and rotor up... There..."

Then once word gets around that "he climbs", the older guys call saying they need "just a little help with my tower" that they put up in the 80s when they were young and spry enough to climb it themselves.

Next the ham club decides its time to "refresh" all of the antennas at a site on all bands, or they decide to move to a new tower, and you're ordering feedline, grounding kits, rolls of Scotch 33 and 88+ and having large trucks deliver boxes with huge antennas in them to your workplace because they have a loading dock, and a month later you're up a tower all day rigging pull lines so the six guys wandering around on the ground will hoist a 100 lb monster up so you can try to get it into place on a 3" pipe mount.

Heh. It just snowballs. I climb slow, I work medium speed but way slower than a few pros I've climbed with, and I just try to be safe. Lots of OTJ training from pro-trained guys. They're nuts.

Here's a fun one... The airport beacon at KLMO is on a tower. It didn't used to be. Cellular companies wanted a site near the airport. They bought the tower and stuck it on the airport and moved the beacon back in the mid-90s.

On the VFR chart, it's just the star for the beacon location.

On the GPS-B is the only approach plate you'll find it on, even though it's on the airport.

It's the 5093'. About a 50' tower or so. (It sits downhill from the buildings.)

I hung a couple antennas on it (with permission) many years ago to monitor 121.5 and transmit an alert to a local ham radio repeater if an ELT was squawking.

There were dudes there painting the tower the FAA's official warning orange color that day. They were swinging around like monkeys under the platform up at the top where the beacon sits, painting the bottom of it. They kept dropping paint on my hardhat and work clothes. Heh heh.

I had a "photo mission" to shoot photos of my buddies in the ham radio group out on top of the Mesa near Limon, CO where they'd set up for June VHF.

The Mesa is covered with towers but I'd had both the experience of knowing exactly where they all were at ground level and seen them all up close (including their guy systems for those that aren't free standing) and had studied the layout enough that I knew a 500' AGL north-south pass (uninhabited ranch land up there) would pass between all the towers with plenty of room on either side with a nice West shot in the morning so they'd be lit properly.

Today there are a pile of windmills up there and you couldn't do it safely. So I'm glad we got the photos the year we did.

Also today, I'd be trying to use Foreflight and I'd be annoyed with the charting mess out there.

The area near Limon, CO (KLIC) is one of the most god-awful chart "stitching" areas I've seen yet on Foreflight.

I wish they'd set it up so you could peel the layers off in overlap areas, like this one.

There are a pile of obstructions there that "disappear" at different zoom levels on top of that low ridge because three charts run into each other there.

Some examples...

Kinda zoomed...

The worst case scenario, fully zoomed at the corner of three charts...

Backing up a bit, it's better. But messy.

Note the chopped up stuff to the West where the two Terminal Area charts start for KDEN and KCOS...

And there is a completely missing option there too. There is a combined KDEN/KCOS Terminal Area Chart available. But it's not used in any of the stitching around KDEN that I can tell. If its used, it's seriously jacked up by the more specific Terminal Area Charts for KDEN and KCOS.

Whoever provides the FF charts doesn't seem to realize that one chart would look and work a whole lot better than using the two separate Terminal Area charts.

Out near Limon, I definitely prefer paper charts.



Ohhh well. There's a topic thread tangent to get us back on flying topics!

 

[rainsux]

Sometimes the charts are wrong, if visibility is limited, give them wide(r)
berth.

Thinking of the case a few years ago where a plane hit a tower in Wi. The
chart showed the tower on the west side of the road, so they stayed to the
east of the road. The chart was wrong.

 

[Capt. Geoffrey Thorpe]

If visibility is good they are easy to spot against the sky if you are low enough. But if visibility is not good and you are that low, you really need to be asking yourself why you aren't already on the ground.

 

[roncachamp]

Re: Obstruction on map, where is it exactly?

I was wondering about antennas that I see on my sectional. Since the antenna drawing takes up some space, where should I expect the base of the antenna to be...at the bottom of the drawing? There are some antennas near my airport and I see them on the map but have never figured out exactly where I draw my course to avoid them. And for that matter, the tops of things.....are they right at the top of the pointy spot of the mountain? Suggestions?

Which antennas?

 

[murphey]

Re: Obstruction on map, where is it exactly?

Which antennas?

From the OPs comments, it's primarily the area NW of Denver, near Erie (EIK). There are a couple 1000 ft towers very close to EIK. For those of us familiar with the area, we use them (visually, and not too close!) to verify the 1000 pattern altitude...(*snicker*)

Don't get the locals started on the 1995 ft tower out by Hoyt (just east of the 30 nm mode C circle around Denver).