What my antennas "see"

[bobruzzo]

I mounted a Go Pro camera on the tip of a bunch of long bamboo poles duct taped together and was able to get up to the area where my antennas are. I made a video and took a few still shots from it. I was curious to see what it looks like from the antennas point of view. I am looking slightly west/northwest. The land rises pretty high out in that direction. I have a clearer shot to north and south. East is obstructed by trees and another closer HUGE hill. I was thinking about getting some heavy duty ballons to do another experiment but that might be a bad idea. I'd like to be able to take a look another 15 feet higher. But it seems I clear close by obstructions pretty well except to my east. It's almost a clear shot to horizon in other directions.

 

[Thunderknight]

Another option is a drone. Do you know anyone who has one? Doesn't need to be a fancy one. You can easily go up say 10 feet at a time, do a 360 view, another 10 feet, another 360, etc. Then you can determine how high you would need to be to get the "view" you want.

 

[bobruzzo]

Another option is a drone. Do you know anyone who has one? Doesn't need to be a fancy one. You can easily go up say 10 feet at a time, do a 360 view, another 10 feet, another 360, etc. Then you can determine how high you would need to be to get the "view" you want.

I just thought of that. I have a friend who is a realtor who uses a drone to do house videos. I should see if he could bring drone over. At some point anyway.

 

[fxdscon]

I just thought of that. I have a friend who is a realtor who uses a drone to do house videos. I should see if he could bring drone over. At some point anyway.

Another interesting way to see what your antenna can "see" (meaning geographical obstructions) is the "elevation profile" tool in Google Earth Pro.

This pic shows the elevation profile from my summer residence in NH (left side of the graph @525' above sea level) due east to the ocean just off Cape Elizabeth, ME. The vertical line on the graph can be moved along the path to the various elevations, and the red arrow on the map will be pointing directly to the location of that area.

 

[bobruzzo]

I downloaded the Google Earth Pro and its pretty nice but how do you find the elevation tool? Looked all over but cant find it!

 

[fxdscon]

I downloaded the Google Earth Pro and its pretty nice but how do you find the elevation tool? Looked all over but cant find it!

It is buried a little bit if you're not familiar with using it. From the top tool bar in Google earth, click on the ruler icon. In the window that pops up, be sure the "line" tab is selected. For longer distances, I usually select "miles" for the map distance in that window. Left click and release on the map (your house) to start a line measure, and left click and release where you want the line measure to end. click the "save" button, and then click "ok" in the next window that pops up.

Look over in the left side of the program window... there should now be an entry under "places" that is labled "line measure". Right click on that, and choose "show elevation profile" from the drop down menu.

Once you get used to using it, it's a very valuable tool for antenna and reception work.


This is a help page from Google:

Measure distance & elevation - Google Earth Help

Use lines and shapes to check distances and estimate sizes of different features on Earth. What you can measure in Google Earth Pro: Polygo

support.google.com

.

 

[bobruzzo]

It is buried a little bit if you're not familiar with using it. From the top tool bar in Google earth, click on the ruler icon. In the window that pops up, be sure the "line" tab is selected. For longer distances, I usually select "miles" for the map distance in that window. Left click and release on the map (your house) to start a line measure, and left click and release where you want the line measure to end. click the "save" button, and then click "ok" in the next window that pops up.

Look over in the left side of the program window... there should now be an entry under "places" that is labled "line measure". Right click on that, and choose "show elevation profile" from the drop down menu.

Once you get used to using it, it's a very valuable tool for antenna and reception work.


This is a help page from Google:

Measure distance & elevation - Google Earth Help

Use lines and shapes to check distances and estimate sizes of different features on Earth. What you can measure in Google Earth Pro: Polygo

support.google.com

.

OK I got it. Very interesting. The results are consistent with why I can't hear the new P25 system to my east. From my house, due east is 0.66 miles. My elevation is close to 90'.......and at top of hill it rises to 189 feet. Then on other side of that hill the land slopes down again. However It doesnt affect many ANALOG signals from way over that hill, well into Massachusetts. So next I will test it from the other 3 directions and see what I get.

 

[nd5y]

The Google Earth elevation profile is nice but it only measures ground elevation. It doesn't take into account the curvature of the earth. It's no good for long paths. For example you can draw a line from Pike's Peak, CO to Mt. Washington, NH or from Mauna Kea, HI to California and it appears to be line of sight with no terrain in between.

 

[TerryPavlick]

Try this web site

HeyWhatsThat Path Profiler

Compute elevation profile for an arbitrary path

www.heywhatsthat.com

Terry

 

[nd5y]

If you want actual radio coverage prediction then you need to use something like Radio Mobile or SPLAT!.

 

[bobruzzo]

I am doing just short range measurements, just a few miles. I want to get a look at possible obstructions. It is interesting.....It seems I have a big high ridge to my east, To the entire west direction the land rises to over 400'. But there isn't anything to hear in that direction anyway, except for the Killingly, CT fire dept. which I can hear, but a little scratchy. And to my south and north, there are a few high spots but they are miles away from me. Most of what I listen to is to the east, north and south. Local P25 systems are fine except for one new system just set up. And its to my east! So I cant hear it. All other analog stuff comes in really good, even far out to the east into Massachusetts. Using a discone up bout 25' and an 800 mhz mag mount for P25.

 

[fxdscon]

I am doing just short range measurements, just a few miles.

Exactly. For the short distances involved in scanner reception range, Google elevation profiles are a very useful tool.

.

 

[buddrousa]

bobruzzo
Nice view but on the right side of the picture over the stop sign on that hill I see where I would want my Antenna.

 

[bobruzzo]

bobruzzo
Nice view but on the right side of the picture over the stop sign on that hill I see where I would want my Antenna.

Hahahahaha yes thats up in Johnston, RI and elevation very good up there. That tower is near the state landfill. And its up pretty high. Well, high for Rhode Island.

 

[buddrousa]

Would you mind showing us the street view of you antenna and how it is mounted?
I have a 25 to 30 foot ST2 but planning on a 50 foot Rohn 25g tower with beams and the ST2 12 to 13 foot above the nose I will post Pictures when project is done this summer.

 

[bobruzzo]

Would you mind showing us the street view of you antenna and how it is mounted?
I have a 25 to 30 foot ST2 but planning on a 50 foot Rohn 25g tower with beams and the ST2 12 to 13 foot above the nose I will post Pictures when project is done this summer.

Here is how I set up my antennas. The discone is on a 10' pipe attached to two 4" side mount brackets. I tried getting the whole thing up as high as I could. Originally I wanted to mount in center of the garage wall up to peak but ladder not tall enuff. Used a thick copper ground wire going from bottom of mast to 8' copper rod in ground. The second mast with vertical dipole was added recently. Gotta ground it soon. The dipole cut for aircraft band. I live close to state airport. But that antenna may be replaced with a 800mhz yagi this Summer so I can pick up Mass State Police. I can lower the dipole down the mast a little. I just cant seem to find an 800mhz yagi that I trust will work. Plus I will have to get good coax like LMR 400 and an N-connector on one end of coax. All the yagi's seem to have N connections. The coax for the antennas run across top of garage roof and along gutter on patio roof up into window of my studio. I would like to raise antennas up higher but I think this is the limit for me.

 

[buddrousa]

Looks nice and and neat nice to see the ground wire used You could use Rohn 25G tower and a house bracket if you do not load the tower above 10 square feet of Antennas you could go 30 feet above the peak of the garage without having to use guy wires that would give you 60 feet or so above the ground with no guys and could still use a rotor if you wished.

 

[bobruzzo]

Looks nice and and neat nice to see the ground wire used You could use Rohn 25G tower and a house bracket if you do not load the tower above 10 square feet of Antennas you could go 30 feet above the peak of the garage without having to use guy wires that would give you 60 feet or so above the ground with no guys and could still use a rotor if you wished.

I thought about a small tower but remembering what I went thru back in early 90's when I moved into a new house. I was given a small 30' tower and had planned to put it in back of house. We lived on a decent hill at that house so the 30' tower was good. But all the crap to get that thing up! I am too old to be digging and fighting with town and neighbors! Back then, the building inspector was a jerk and gave me all kinds of excuses. I asked him about all the ILLEGAL CB towers in the area and he couldnt answer that. Luckily my wife had relative who was structural engineer so he helped me, and the fact I was a HAM helped too. So I built a scale model of my house out of popsicle sticks with a tower made on paper clips all bent straight. He was so impressed he ok'd the paperwork and I returned to building inspector. The guy recognized me and saw the approval and growled at me and gave me permit. They were mostly concerned that the tower, if it fell, stayed within your property. I showed them a 30' tower, regardless of which way it fell, would be within my property and not even come close to landing on anything or power lines.

 

[Ubbe]

You can also use this tool. RF Line of Sight - SCADACore

/Ubbe

 

[buddrousa]

Yes I have been there done that. I am 62 still own the Rohn Factory Gin Pole I bought when I was 16 I only climb for myself now but I have the Rohn Factory Tower Book with all the specs and have very little trouble anymore I did several 180 foot Rohn 25G towers for Fire Departments over the years as a friend.