Somewhat basic tower/scanning question

[empired987]

Sorry in advance if this is a stupid question, but I’m fairly new to this stuff. I’ve tinkered with handheld and mobile scanners in the last 2 years, and I understand how the different types of radio networks and bands work. I recently got into SDR scanning, I have 2 dongles setup to scan both MDICE and Starcom.

Within Champaign County, I’m currently able to pick up the entire MDICE system, as well as the Champaign Starcom21 tower with no issues. I don’t, however, have any experience with towers, or any type of external antennas.

So my question is this (again, sorry if it’s stupid). I would like to be able to pick up signals from surrounding counties. I’m not looking for anything crazy like picking up the Indiana SAFE-T system, I’m just looking to pick up McLean, Vermilion, or Macon towers (if that’s not crazy either, again I’m not sure). With that being said, how tall of a tower would I be looking at to accomplish this? For reference, I’m basically in the center of Champaign county. Second, if the above is reasonable, what type of antenna is recommended for something like that?

Distances:
LeRoy/McLean: ~35mi
Argenta/Macon: ~35mi
Danville/Vermilion: ~30mi

Again, I'm fairly new to this, so any help would be much appreciated.
PS: Not sure if this is the correct forum, I just placed it here because of Starcom21 and MDICE

 

[mmckenna]

It entirely depends on your exact location.

These frequencies work mainly by line of sight. They won't penetrate hills, however sometimes atmospheric conditions can change that. It's not reliable, though.

So, best way to do this is to start playing with some of the features on Google Earth. You can mark your exact location and the exact location of each of the towers. There is a "ruler" function that will let you draw a line between them, then a feature that allows you to look at the path cross section. That'll let you see if there is too much dirt in the way.
But don't forget to figure in the curvature of the earth, also. If the antennas are down low enough, that becomes an issue. You'll need to know the antenna height for the transmitter you want to hear, that ~should~ be on the FCC license. Enter that and then play around with your antenna height and see what gets you to 35 miles.
Distance to Horizon at Altitude
Just remember to set the measurements to feet and the output to miles. It defaults to meters.

Even if there is not direct line of sight, it may still work, but may not be reliable.

Keep in mind that the guys that engineer these systems design them to cover the agency jurisdiction. The FCC license dictates power output, antenna height, etc. It also dictates the radius around the center point (usually the repeater) where the mobiles are allowed to transmit. They don't put money into sending coverage out into areas that are not in the jurisdiction.

So, after you've done all the math, plotting, design, it still comes down to a bit of "put an antenna up and try". One easy thing you can do is take a receiver/scanner/dongle up on the roof and see if you can hear the systems from up there. If you can, that means that simply putting a suitable antenna on the roof will often work.

 

[scanmanmi]

A few questions. Are you just trying to pick up 800 trunked systems or other frequencies? Have you tried any outside antennas?
Go to Google Earth, click Add then Path. Click your location and then the transmitter location and hit OK. Right Click the path (the mouse will not change) and click View Elevation Profile. If you want to adjust antenna height right click the path and go to properties, altitude. This may help in determining any height you may need.
www.scannerschool.com

 

[empired987]

So, best way to do this is to start playing with some of the features on Google Earth. You can mark your exact location and the exact location of each of the towers. There is a "ruler" function that will let you draw a line between them, then a feature that allows you to look at the path cross section. That'll let you see if there is too much dirt in the way.
But don't forget to figure in the curvature of the earth, also. If the antennas are down low enough, that becomes an issue. You'll need to know the antenna height for the transmitter you want to hear, that ~should~ be on the FCC license. Enter that and then play around with your antenna height and see what gets you to 35 miles.
Distance to Horizon at Altitude
Just remember to set the measurements to feet and the output to miles. It defaults to meters.

I will for sure try this and see how it works! If it magically comes down to roof level, I might also try the other suggestion and try to take a simple antenna to the roof and see if I pick anything up, but I doubt it.

Again, thanks for getting back and helping out!

 

[Bri112233445]

I know for sure if its Starcom right next to your county you can possibly pick it up I live in Kendall County and can pick up the Kane And Will/Grundy sites fine just depends on your location. Use the map below to map the towers around you.

Illinois StarCom21 - Google My Maps

For more information, check out the StarCom21 profile at http://www.carmachicago.com

www.google.com

 

[Patch42]

You got a pretty complete answer from mmckenna so I'll just add that when my father put a discone on top of the TV antenna that was already on the roof his range pushed out to about 40 miles, give or take depending on the target transmitter. This was back in the days when everything was analog so I can't say if many of these now being digital would have an impact.

 

[empired987]

Thanks everyone! I checked google maps and went through the above steps. At about 50 feet there's little to no obstructions, but I'll likely try putting up a roof antenna before going any further. And yes, it'd be 800mhz.

 

[mmckenna]

Thanks everyone! I checked google maps and went through the above steps. At about 50 feet there's little to no obstructions, but I'll likely try putting up a roof antenna before going any further. And yes, it'd be 800mhz.

An 800MHz Yagi/directional antenna may help.

 

[west-pac]

Thanks everyone! I checked google maps and went through the above steps. At about 50 feet there's little to no obstructions, but I'll likely try putting up a roof antenna before going any further. And yes, it'd be 800mhz.

I receive Vermillion county, IL VHF DMR channels on my SDR almost 24/7 near Hartford City, Indiana (roughly 120 miles line of sight). I use a Comet CX333 vertical antenna on my roof, 25 feet above ground level, as my antenna for my scanners and SDR.

I have a Wilson 301111 800Mhz yagi that I use occasionally as well. I find that it offers more range on 800Mhz, than my CX333, but it's certainly not as directional as it should be. I can receive 800Mhz towers 40 miles away off the back of the beam that my CX333 can't hear, yet everyday I listen to an 800Mhz site 25 miles away on my CX333. For the Wilson 301111 being an 8 element beam I would've expected more directivity, and more rejection to the rear than what I'm actually seeing.

 

[jonwienke]

The antenna might not be the problem, if there is something reflective in the opposite direction from the tower bouncing signal back to you.

 

[VASCAR2]

The LeRoy site has good coverage on Starcom 21 and I was able to listen into Champaign County in my car with my BCD325P2. I suggest you unlock some of the talk groups your interested in listening to make sure your not able to receive some of the surrounding counties. Douglas County Sheriff is on Starcom District 10 site which you should be able to receive in Champaign. Location is everything with two way radio but it is not uncommon for Talk Groups to be transmitted on more than one site.

Unfortunately more agencies are using encryption so there isn’t as much to listen to in McClean County. Be sure to order the correct coax cable for your outdoor scanner antenna. There is a lot of signal loss with the higher frequencies on the coax like RG8.

 

[empired987]

The LeRoy site has good coverage on Starcom 21 and I was able to listen into Champaign County in my car with my BCD325P2. I suggest you unlock some of the talk groups your interested in listening to make sure your not able to receive some of the surrounding counties. Douglas County Sheriff is on Starcom District 10 site which you should be able to receive in Champaign. Location is everything with two way radio but it is not uncommon for Talk Groups to be transmitted on more than one site.

Unfortunately more agencies are using encryption so there isn’t as much to listen to in McClean County. Be sure to order the correct coax cable for your outdoor scanner antenna. There is a lot of signal loss with the higher frequencies on the coax like RG8.

What Coax do you recommend? I do indeed hear a lot of Douglas County traffic, even on the Champaign site (I don't monitor the Pesotum site).

 

[VASCAR2]

LMR 400 seems to be most recommended these days. I had a 35’ tower and a Antenna Specialist multi band antenna with RG 8 or RG 58 coax. It’s been so many years ago I don’t remember which but I needed at least 50’ of coax. Once agencies started migrating to 800 MGHz my reception was better on the pull up supplied scanner antenna as my tower on 800 MGHz. A wind storm and rust destroyed my tower so I had to take it down. I’m currently using a magnetic mount cell phone antenna (from an old bag phone) in a window hooked up to my BCD996XT. I get three Starcom sites and five Indiana Safe-T sites at my house. I can get a site in Indiana that is 37 miles from my house but can’t get a Starcom site that is 32 miles away. The terrain is more forgiving north and east of my house.

The terrain affects me more on reception than anything else in this digital age. With analog land mobile radio (LMR) I got better distance reception on analog than the digital. Signal strength is more critical with digital as it seems to be enough to decode or not enough to decode. I notice terrain affects my Digital TV more than distance compared to when we had analog TV. Foliage negatively affects digital signals range more than analog especially on 700/800 MHGz.

I read RG 6 which is typically used with Satellite dishes to control boxes and TV’s is better than RG 8/58 but it is not very good for 800 MHGz scanner use in my opinion. The construction of your residence can be a factor as metal roofs and metal constructed buildings seem to hinder reception.

Height is your friend if your going to use an outside antenna. I prefer omnidirectional antennas at my location but I’m rural and am not near simulcast systems or sources of strong RF interference.

 

[Violation]

You won'hear much from Vermilion County Sheriff or the City of Danville, either. Both are encripted as of several years ago. I know this from living here.......PJ

 

[Starcom21]

https://www.scadacore.com/tools/rf-path/rf-line-of-sight/?fbclid=IwAR1P4c8RDBvWc945Mn-FMeazseBoaMPwyym4F-csmEEkrA9c6ESkCtqMVlg

 

[VASCAR2]

That is a good web site, thanks for posting Terry!

 

[jonwienke]

You can do the same thing on a saved distance measurement in Google Earth.