Yagi Antenna Recommendations

Tokyoblue

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Dec 17, 2014
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Good morning everyone,
A newbie scanner here.I have been reading alot of threads about the simulcast distortion currently on the P25 system.Myself I cannot afford the SDS 100 or 200.I am currently using a Bearcat 996T.I live in a area where we have alot of towers which is causing my distortion issues.I listen to my local airport. My question and concern is,will a Yagi antenna help with the P25 distortion, and since I listen to the aircraft freqs, how bad will I suffer listening to those freqs?
 

jim202

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I don't have a direct answer to your trunking tower problem directly. But would suggest you take a map and plot the location of all the towers in the trunking system. This will give you an idea if your closer to any one of the towers. If so, then a directional antenna for listening to the trunking system will help.

As for the airport traffic, that is a hard call to make. It will possibly kill your reception when you install a yagi for the trunking system. Combining 2 antennas will probably cause your trunking distortion to go back to what you started with. My suggestion would be a second scanner just for your airport traffic.
 

mmckenna

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Good morning everyone,
A newbie scanner here.I have been reading alot of threads about the simulcast distortion currently on the P25 system.
"P25" isn't a specific band or frequency. It's an emission type.

Antennas are designed around frequencies/bands, not emissions, so without knowing which frequencies the trunked system is on, no one will be able to give you an accurate answer.
 

Tokyoblue

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I don't have a direct answer to your trunking tower problem directly. But would suggest you take a map and plot the location of all the towers in the trunking system. This will give you an idea if your closer to any one of the towers. If so, then a directional antenna for listening to the trunking system will help.

As for the airport traffic, that is a hard call to make. It will possibly kill your reception when you install a yagi for the trunking system. Combining 2 antennas will probably cause your trunking distortion to go back to what you started with. My suggestion would be a second scanner just for your airport traffic.
 

Tokyoblue

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Hi
Thanks. For the reply,after I read your post I agree that would probably be the only way to scan airport frequencies and still monitor the digital trucking channels. Here in Ohio the simulcast distortion here is pretty bad. I can live with it for now if I can get a Yagi antenna that would help out. I can’t afford one of those SD 100 or 200 for now.
 

iMONITOR

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I live in a area where we have alot of towers which is causing my distortion issues.I listen to my local airport. My question and concern is,will a Yagi antenna help with the P25 distortion, and since I listen to the aircraft freqs, how bad will I suffer listening to those freqs?
Is the firmware in your BCD996T updated? What are you using now for an antenna? How is your signal level with that antenna.

Sometimes a Yagi antenna can exacerbate the problem. Sometimes you want to lower the signal level to help eliminate or decrease the signal from as many of the offending towers as possible.
 

Tokyoblue

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Dec 17, 2014
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Is the firmware in your BCD996T updated? What are you using now for an antenna? How is your signal level with that antenna.

Sometimes a Yagi antenna can exacerbate the problem. Sometimes you want to lower the signal level to help eliminate or decrease the signal from as many of the offending towers as possible.
 

WA0CBW

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Looks like you could use some waterproofing on the antenna connector/adapter. Supporting the coax so that the connector is not supporting the coax would be a good idea as well. If the mast is metal the ground plane of the mast should be nearly even with the top of the mast. If the mast is not metal there should be a ground wire connected to the antenna ground (plane) going to a ground rod at ground level. That ground rod should be connected to the house main panel ground rod(s).
Bill
 

Tokyoblue

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Looks like you could use some waterproofing on the antenna connector/adapter. Supporting the coax so that the connector is not supporting the coax would be a good idea as well. If the mast is metal the ground plane of the mast should be nearly even with the top of the mast. If the mast is not metal there should be a ground wire connected to the antenna ground (plane) going to a ground rod at ground level. That ground rod should be connected to the house main panel ground rod(s).
Bill
Looks like you could use some waterproofing on the antenna connector/adapter. Supporting the coax so that the connector is not supporting the coax would be a good idea as well. If the mast is metal the ground plane of the mast should be nearly even with the top of the mast. If the mast is not metal there should be a ground wire connected to the antenna ground (plane) going to a ground rod at ground level. That ground rod should be connected to the house main panel ground rod(s).
Bill

The ground is at a different location. I just put that up like a couple days ago just to see how it would operate. Thanks for pointing out some things I missed.What are your thoughts about the question about the Yagi antenna.
 

Ubbe

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Buy one of those cheap $30 yagi antennas for 700-900MHz that are refered to in some other posts. If you are lucky it will still receive something from the airport, if you point it in that direction and it happens to be a direction that also improves reception of the simulcast systems.

If the simulcast systems are all in the 400-900Mhz range then you could get a $35 low pass filter that goes up to 300MHz and put that in line with your current antenna coax and connect together with the yagi. If simulcast are only at 700-900MHz then use a low pass filter that goes up to 500MHz. Mini-Circuit got different connector types to choose from.

Mini-Circuit low pass filter
Low pass up to 500Mhz

/Ubbe
 

Tokyoblue

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Buy one of those cheap $30 yagi antennas for 700-900MHz that are refered to in some other posts. If you are lucky it will still receive something from the airport, if you point it in that direction and it happens to be a direction that also improves reception of the simulcast systems.

If the simulcast systems are all in the 400-900Mhz range then you could get a $35 low pass filter that goes up to 300MHz and put that in line with your current antenna coax and connect together with the yagi. If simulcast are only at 700-900MHz then use a low pass filter that goes up to 500MHz. Mini-Circuit got different connector types to choose from.

Mini-Circuit low pass filter
Low pass up to 500Mhz

/Ubbe
Thanks for the info. Will look for a Yagi you mentioned.
 

cmdrwill

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Actually the corner reflector antenna works better to avoid signals from other cells. multi path. As compared to a yagi antenna.
 

bobruzzo

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I have struggled since day 1 with (Radio SDS200) simulcast distortion. Yes even the SDS200 isn't immune totally. In desperation I got a couple of YAGI's and I found if I pointed the yagi completely AWAY from the areas where towers are located, my simulcast distortion almost 100% cleared up. We have a 4 site system here. Towers are to the north, south and east...some of them close within 5 - 8 miles. So maybe the problem was TOO MUCH signal. Yagi is pointing towards the northwest where there are no P25 system towers.....I can now hear all 4 zones pretty clearly with full scale signals. I am using an 8 element yagi. My other 6 element yagi is used for monitoring on SDR, a DMR commercial site which is VERY active. The only VERY weird thing is I ordered a new BCD996P2 to use when I am in car, but I use in radio room too. That radio is connected to an 800mhz mag mount antenna on small ground plane up on 2nd floor gutter. I get virtually NO simulcast distortion with that setup. The reception is so good I often use that instead of the SDS200. So antenna placement is VERY important, but its a needle in haystack cause you can't "see" RF....My neighbors were probably wondering why I was spending so much time up and down ladder adjusting my yagi all summer. Wife mentioned it too. I did find that HEIGHT didn't make any difference with the yagi. So it's only up about 16' off ground. See it in the picture.
 

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Ubbe

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So maybe the problem was TOO MUCH signal.
If you have signals up in the -60dBm levels it starts to go into intermod with a lot of ghost frequencies being produced. Even at -80dBm there are interferencies from channels at about 175KHz and 350KHz distance and some other places. Try and keep all signals levels as low as possible to try and avoid any problem. Different filter settings and IFX change where in frequency the ghost interfering signals appear so it might be possible to find a setting just right where you do not have transmitters at the interfering frequencies.

/Ubbe
 

scanmanmi

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I am using a yagi for distance but I have a ground plane mounted above my yagi and it seems ok. Running two antennas together can get complicated like the length of coax and spacing (which I did not do). Like Bob said you'll have to play around with it. Currently I am considering a dedicated scanner for 800 and another for everything else. Seems like we expect too much.
 

bobruzzo

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I am using a yagi for distance but I have a ground plane mounted above my yagi and it seems ok. Running two antennas together can get complicated like the length of coax and spacing (which I did not do). Like Bob said you'll have to play around with it. Currently I am considering a dedicated scanner for 800 and another for everything else. Seems like we expect too much.
Yeah there are some compromises. I get much better results using a yagi for p25 simulcast. And the SDS200 has better sensitivity than my BCD996P2. I am only using the SDS200 for monitoring just 2 systems. The local 4 site P25 and a Motorola 800mhz Mass State PD. I didnt want to clutter up the radio and slow it down by programming a ton of other stuff. So its a very expensive radio to only monitor 2 systems! I tried discone, omni x and got lousey results. So in my case the yagi works best. But I had to spend a long time trying different positions and heights.
 

Kaleier1

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Dec 27, 2019
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Buy one of those cheap $30 yagi antennas for 700-900MHz that are refered to in some other posts. If you are lucky it will still receive something from the airport, if you point it in that direction and it happens to be a direction that also improves reception of the simulcast systems.
$30 is way too much. Mine was $15.62 shipped free.
 
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