Current setup is a Uniden BCD996xt with the radioshack 800mhz rubber antenna on the back of it and 90 degree adapter. Most of the time scanner says NFM or has a control channel with no talking. Sometimes if I happen to be looking at the scanner it will lock in on someone talking, but nothing comes out the speaker. Other times the talking is garbled, not to often is it clear. If I move the scanner around the house or move it even a couple inches it will help reception for a little while, then it goes away. The closest tower is about 2-3 miles away, but in that same direction are towers behind it but probably 20 miles away. Between me and the closest tower are trees and maybe a slight hill. Figure could install a yagi on the roof somewhere and see if that helps. Which yagi would be a good choice for receiving signal from a close tower but not ones behind it or to the side?
Best antenna for getting a close tower site 800mhz
- Thread starter hrc200x
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If they are in the same direction the best answer is to weaken the signal to eliminate the long range sites....
I_am_Alpha1
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There are about a hundred factors involved here. Tons of information is needed. Analog vs digital, P25, Phase 1 or 2, Trunking, encrypted, transmitter beamwidth, etc, etc, etc. A yagi would be the worst thing you could do. Try the attenuator. Try using a VHF rubber duck antenna--or no antenna. Remember there is nothing on the market that is good at receiving the digital P25 signals on a trunking system--poor, but not good.
br0adband
Member
Did you program the system you want to monitor and use CC only mode (where it does all the "programming" for you by just pulling info from the control channel itself)? If it's a trunked 800 MHz system all you should be required to do is create a system and make sure it's in CC only mode and program it with the necessary CC frequency or frequencies if there's more than one on that system (the RR database should be able to help with that info), and start scanning it.
Also, is the scanner's attenuator currently on? If it is, that'll reduce the effective signal the scanner works with by about 20 dB which is a huge amount and can basically kill it entirely in some situations making the signal unusable to any degree - it almost sounds like that might be part of the problem here so definitely check on that. If you see ATT on the display (I don't own a 996XT or any physical scanner anymore but I do know from owning a BC246T years ago it would display ATT for attenuator when that was active) then you need to disable it using the proper menu entry. By default it should be off for all systems and needs to be manually enabled (which could have happened during programming hence me mentioning it).
You can also look up exactly where the given tower(s) are located for that system with the RR database info - in the section where it lists the frequencies for the system, look at the System Name entry and it should be a link that'll take you to a site-specific entry where it'll show you on a map as well as provide latitude and longitude coordinates.
If you're 2-3 miles away from such a site, hell, you should be able to get a rock solid signal even with no antenna attached because of that proximity. If the tower(s) are actually 20 miles away then yes you'll need to ensure you're getting a good signal so that would indeed need a decent antenna. The RS 800 is still one of the best antennas ever made IMO, and it's never failed me to pulled in signals anywhere I've used it (in basically every continental US state so far) but your actual location will obviously make a difference in the reception. You could always get an extension cable for the RS 800, maybe one of those suction cup window mount style extensions and run it away from the scanner itself to a window facing the direction of the towers - again the point here is that changing anything can sometimes end up making all the difference, and just like with cell phones where you can be standing in one place and get almost no signal but simply turning your head 15 degrees one way or the other magically gets a solid signal is the same with any antennas, even those for scanners. Moving the antenna up, down, right, left, or away from the scanner itself using an extension cable could be what makes the most difference.
Before considering a Yagi you need to do that research and figure out precisely where the actual site tower(s) are located so you know for sure where the signal(s) should be coming from. Once you do that, it's entirely possible that just moving around in your location (home, apartment, whatever) might help or using an external antenna mounted by a window in the direction of the signal(s) might help. You could also build one of these for under a few bucks (the cost of the SO-239 chassis mount itself and a coat hanger):
The top (main) element should be 3.45" long at 855 MHz which is the middle of the 800 MHz public service band (it'll insert into the top connector on the SO-239 mount), and the ground plane elements should be slightly longer but not much, maybe 3.75" or so. Takes like 5-10 mins to make one and it can make a rather dramatic difference with 800 MHz reception - also good for 750 to 950 MHz operation to but, since they're so cheap you could make ones for those bands specifically as well if you wanted using antenna wavelength calculations from the Frequency Wavelength Calculator.
The fun part is the experimentation to find something that works better than what you've currently got. A Yagi would be excellent for pulling in signals from a long distance because that's what it's designed to do: focus the gain and reception in a specific direction (with the Yagi pointed in the direction you want to grab signals from - think of a Yagi like a big arrow pointed in that direction).
You're making it sound like an analog radio signal and a digital radio signal are something unique and different at the same time: they're the same as there's no such thing as an "analog" radio signal or a "digital" radio signal - there are only radio signals, period. The difference comes from the type of modulation (AM, FM, SSB, etc) and perhaps the actual content being transmitted by the radio signal itself: analog or digital in that respect.
As for the Yagi comment, in the OP's situation if the site(s) he or she is actively trying to monitor do happen to be 20+ miles away, and potentially over a slight hill or curvature of some kind then yes, a Yagi would indeed help in some degrees to get them pulled in with much better reception of the weak(er) signals.
And if there's nothing out there but poor antennas for signals from trunked P25 systems, then the millions of us using scanners and SDR sticks to monitor such signals and systems with antennas of all shapes, sizes, and construction materials from empty 2L bottles laced with coat hangers and others like the pictured above to the higher end commercial discones that sell for $1500 must be doing something wrong.
(if worse comes to worse you can always factory reset the 996XT and start totally from scratch - it can be a pain the keister but sometimes a good fresh start can make all the difference)
Also, is the scanner's attenuator currently on? If it is, that'll reduce the effective signal the scanner works with by about 20 dB which is a huge amount and can basically kill it entirely in some situations making the signal unusable to any degree - it almost sounds like that might be part of the problem here so definitely check on that. If you see ATT on the display (I don't own a 996XT or any physical scanner anymore but I do know from owning a BC246T years ago it would display ATT for attenuator when that was active) then you need to disable it using the proper menu entry. By default it should be off for all systems and needs to be manually enabled (which could have happened during programming hence me mentioning it).
You can also look up exactly where the given tower(s) are located for that system with the RR database info - in the section where it lists the frequencies for the system, look at the System Name entry and it should be a link that'll take you to a site-specific entry where it'll show you on a map as well as provide latitude and longitude coordinates.
If you're 2-3 miles away from such a site, hell, you should be able to get a rock solid signal even with no antenna attached because of that proximity. If the tower(s) are actually 20 miles away then yes you'll need to ensure you're getting a good signal so that would indeed need a decent antenna. The RS 800 is still one of the best antennas ever made IMO, and it's never failed me to pulled in signals anywhere I've used it (in basically every continental US state so far) but your actual location will obviously make a difference in the reception. You could always get an extension cable for the RS 800, maybe one of those suction cup window mount style extensions and run it away from the scanner itself to a window facing the direction of the towers - again the point here is that changing anything can sometimes end up making all the difference, and just like with cell phones where you can be standing in one place and get almost no signal but simply turning your head 15 degrees one way or the other magically gets a solid signal is the same with any antennas, even those for scanners. Moving the antenna up, down, right, left, or away from the scanner itself using an extension cable could be what makes the most difference.
Before considering a Yagi you need to do that research and figure out precisely where the actual site tower(s) are located so you know for sure where the signal(s) should be coming from. Once you do that, it's entirely possible that just moving around in your location (home, apartment, whatever) might help or using an external antenna mounted by a window in the direction of the signal(s) might help. You could also build one of these for under a few bucks (the cost of the SO-239 chassis mount itself and a coat hanger):
The top (main) element should be 3.45" long at 855 MHz which is the middle of the 800 MHz public service band (it'll insert into the top connector on the SO-239 mount), and the ground plane elements should be slightly longer but not much, maybe 3.75" or so. Takes like 5-10 mins to make one and it can make a rather dramatic difference with 800 MHz reception - also good for 750 to 950 MHz operation to but, since they're so cheap you could make ones for those bands specifically as well if you wanted using antenna wavelength calculations from the Frequency Wavelength Calculator.
The fun part is the experimentation to find something that works better than what you've currently got. A Yagi would be excellent for pulling in signals from a long distance because that's what it's designed to do: focus the gain and reception in a specific direction (with the Yagi pointed in the direction you want to grab signals from - think of a Yagi like a big arrow pointed in that direction).
You're making it sound like an analog radio signal and a digital radio signal are something unique and different at the same time: they're the same as there's no such thing as an "analog" radio signal or a "digital" radio signal - there are only radio signals, period. The difference comes from the type of modulation (AM, FM, SSB, etc) and perhaps the actual content being transmitted by the radio signal itself: analog or digital in that respect.
As for the Yagi comment, in the OP's situation if the site(s) he or she is actively trying to monitor do happen to be 20+ miles away, and potentially over a slight hill or curvature of some kind then yes, a Yagi would indeed help in some degrees to get them pulled in with much better reception of the weak(er) signals.
And if there's nothing out there but poor antennas for signals from trunked P25 systems, then the millions of us using scanners and SDR sticks to monitor such signals and systems with antennas of all shapes, sizes, and construction materials from empty 2L bottles laced with coat hangers and others like the pictured above to the higher end commercial discones that sell for $1500 must be doing something wrong.
(if worse comes to worse you can always factory reset the 996XT and start totally from scratch - it can be a pain the keister but sometimes a good fresh start can make all the difference)
Its a P25 digital trunked 800mhz system. I deleted everything out of the system by holding the 2, 9, and hold button and powering the unit on. I've been fighting this bad signal for the last 4 years. If you search my older posts it probably gives more information in them. I thought by posting something new under antennas that it might get better results or ideas.
I have a very good idea where the towers are and yes, the ones in the background are about 20 miles behind the one that is 3 miles away. There is one other tower I didn't mention yet thats maybe 4-5 miles away but its over a hill and slightly to the north of the 3 mile tower.
Just today I moved my scanner upstairs because could remember it getting better reception on one of the towers 20 miles away before they went to a trunked system here. It gets 4-5 bars and a control channel. Talking is a little garbled, then sometimes clear. I live in a small county so there isn't that much chatter to begin with. Tried turning the attenuator on and it goes down to one bar and only flashes the control channel once in awhile.
I've got the same site programmed into the scanner but two different ways. One which only has the control channel in the frequencies, the other has all the frequencies that the system lists ( 8 or so), seems like once in awhile one will drop the control channel while the other keeps it.
Also, wind seems to have an affect on the signal, when its very windy I can watch the signal strength up and down.
Wish I knew if the problem was a lack of signal or multipath distortion.
I have a very good idea where the towers are and yes, the ones in the background are about 20 miles behind the one that is 3 miles away. There is one other tower I didn't mention yet thats maybe 4-5 miles away but its over a hill and slightly to the north of the 3 mile tower.
Just today I moved my scanner upstairs because could remember it getting better reception on one of the towers 20 miles away before they went to a trunked system here. It gets 4-5 bars and a control channel. Talking is a little garbled, then sometimes clear. I live in a small county so there isn't that much chatter to begin with. Tried turning the attenuator on and it goes down to one bar and only flashes the control channel once in awhile.
I've got the same site programmed into the scanner but two different ways. One which only has the control channel in the frequencies, the other has all the frequencies that the system lists ( 8 or so), seems like once in awhile one will drop the control channel while the other keeps it.
Also, wind seems to have an affect on the signal, when its very windy I can watch the signal strength up and down.
Wish I knew if the problem was a lack of signal or multipath distortion.
Usually I don't go and research someone elses problem, even after they relaunch a topic (and admit to it) that has been brought up before, simply for effect...but all I saw was you looking for antenna ideas. that's that.
It sounds to me like you're going directional antenna before you go up - in a manner of speaking. If you go up in height, even with something as simple as a bare wire - if it improves your reception, you know it's lack of signal. No matter how good a rubber duck antenna is screwed on the back of your unit is, if you put it in a house - as opposed to up and away from all the magical bits in your house that make noise, it will be outperformed by even a rudimentary outdoor antenna.
i'd give it a peak with my little SDR to see visually what makes the signals stronger.
If you have a slight hill that you have between you and the closest target, you need to go up with your antenna. No magical antenna im aware of allows you to go for a specific direction AND RANGE (closest is 2, farthest is 20 mi...yadda,yadda) to prevent multipath or interference. Take your scanner for a walk to the top of the hill, if that 2 mile away source screams in...you know your problem. (a quick view with an SDR would even show it to you). Put a simple wire up on your roof, tape it to a broomstick and hold it out the highest window...elevation may help you here, before you even start spending money.
It sounds to me like you're going directional antenna before you go up - in a manner of speaking. If you go up in height, even with something as simple as a bare wire - if it improves your reception, you know it's lack of signal. No matter how good a rubber duck antenna is screwed on the back of your unit is, if you put it in a house - as opposed to up and away from all the magical bits in your house that make noise, it will be outperformed by even a rudimentary outdoor antenna.
i'd give it a peak with my little SDR to see visually what makes the signals stronger.
If you have a slight hill that you have between you and the closest target, you need to go up with your antenna. No magical antenna im aware of allows you to go for a specific direction AND RANGE (closest is 2, farthest is 20 mi...yadda,yadda) to prevent multipath or interference. Take your scanner for a walk to the top of the hill, if that 2 mile away source screams in...you know your problem. (a quick view with an SDR would even show it to you). Put a simple wire up on your roof, tape it to a broomstick and hold it out the highest window...elevation may help you here, before you even start spending money.
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br0adband
Member
The 996XT ain't a handheld scanner so, taking it for a walk would be somewhat problematic unless the OP has a battery pack or is Superman and can haul a car battery along with him on the jaunt.
As for the attenuator, my intent was to make sure it's off and stays that way not on because if it's on then as you noted the signal strength will decrease to a point of being relatively unusable on this particular system in this situation.
As for the attenuator, my intent was to make sure it's off and stays that way not on because if it's on then as you noted the signal strength will decrease to a point of being relatively unusable on this particular system in this situation.
If you want to try a Yagi, here's an inexpensive one that has worked well for me with analog simulcast sytems:
http://www.amazon.com/gp/product/B0...oh_aui_detailpage_o02_s01&tag=viglink20662-20
I'd stick to a short run of coax, like 10 ft or less, or else go with low loss LMR-400 if you need a longer run. Keep in mind this antenna has a female N connector, so you'll need an appropriate adapter for your coax. And if you use LMR-400, which even in Ultraflex flavor is still pretty stiff, you might want to use a 1 foot jumper of more flexible coax to connect the LMR to your scanner. Also be sure to use some Coax Seal to seal your coax connection at the antenna if you mount the antenna outside.
I would experiment with direction, you might find it works best pointed 90° from where you would expect.
Also, are you running the latest firmware on your 996? I would update it if not, and then try adjusting the hidden P25 settings after the update. I believe 11 and 50 are the recommended settings for P25 Adjust Mode and Adjust Level with the latest firmware installed.
Also, in my experience, no matter how much I tweak them, the 396/996 are just not as good at decoding P25 as my BCD536HP. The newer models just seem to handle this better. Which is why I now have a 436 on order.
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http://www.amazon.com/gp/product/B0...oh_aui_detailpage_o02_s01&tag=viglink20662-20
I'd stick to a short run of coax, like 10 ft or less, or else go with low loss LMR-400 if you need a longer run. Keep in mind this antenna has a female N connector, so you'll need an appropriate adapter for your coax. And if you use LMR-400, which even in Ultraflex flavor is still pretty stiff, you might want to use a 1 foot jumper of more flexible coax to connect the LMR to your scanner. Also be sure to use some Coax Seal to seal your coax connection at the antenna if you mount the antenna outside.
I would experiment with direction, you might find it works best pointed 90° from where you would expect.
Also, are you running the latest firmware on your 996? I would update it if not, and then try adjusting the hidden P25 settings after the update. I believe 11 and 50 are the recommended settings for P25 Adjust Mode and Adjust Level with the latest firmware installed.
Also, in my experience, no matter how much I tweak them, the 396/996 are just not as good at decoding P25 as my BCD536HP. The newer models just seem to handle this better. Which is why I now have a 436 on order.
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I've now read some of your previous posts. So it looks like it's the ARMER system you're trying to monitor, is that correct? And probably the Cook County Simulcast system within the ARMER system? If that is correct, do you have all the Cook County frequencies programmed into your scanner? The database shows one primary control channel, and one alternate. The database could be wrong though, they could be using one of the other frequencies as an alternate. I would double check that all the frequencies are in your radio, and all are unlocked.
What happens if you program the control frequency into a conventional system in your radio, as a conventional channel, with the Audio Type set to Analog Only, and the CTCSS set to OFF. If you hold on that channel, with the squelch set to a low setting like 2 or 3, do you hear the motorboat sound of the digital control channel? Is it a steady, good signal? How many bars? I'm wondering if your problem isn't a nearby cell tower, or some other strong, local signal that is swamping your radio with RF energy and de-sensitizing it.
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What happens if you program the control frequency into a conventional system in your radio, as a conventional channel, with the Audio Type set to Analog Only, and the CTCSS set to OFF. If you hold on that channel, with the squelch set to a low setting like 2 or 3, do you hear the motorboat sound of the digital control channel? Is it a steady, good signal? How many bars? I'm wondering if your problem isn't a nearby cell tower, or some other strong, local signal that is swamping your radio with RF energy and de-sensitizing it.
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Your are correct, its the ARMER system and cook county simulcast. it should be the latest firmware. Even though the scanner was purchased 3-4 years or so ago apparently uniden hasn't updated the firmware since then, as this one came with the most recent on it already.
I have programmed two sites into the scanner both scan cook county simulcast. One just has the control channel and alternate under the frequencies, the other has all 8 of the frequencies. It seems like one will drop the control channel while the other one will keep it, or one drops it faster than the other, but neither work great.
Moving the scanner up stairs seemed to help some, sign of poor reception maybe?, but it still needs tweeking, if the scanner goes quite for awhile, when I check it, it says NFM, then move it around and it gets a control with 3-5 bars. Weather, wind especially seems to have a huge effect on the signal.
Is there any good scanners out there that can do P25 simulcast digital? Before the switch to simulcast here the scanner would pick up tower 20 miles away and get clear talking with only one bar of signal.
I have programmed two sites into the scanner both scan cook county simulcast. One just has the control channel and alternate under the frequencies, the other has all 8 of the frequencies. It seems like one will drop the control channel while the other one will keep it, or one drops it faster than the other, but neither work great.
Moving the scanner up stairs seemed to help some, sign of poor reception maybe?, but it still needs tweeking, if the scanner goes quite for awhile, when I check it, it says NFM, then move it around and it gets a control with 3-5 bars. Weather, wind especially seems to have a huge effect on the signal.
Is there any good scanners out there that can do P25 simulcast digital? Before the switch to simulcast here the scanner would pick up tower 20 miles away and get clear talking with only one bar of signal.
Weather can have an affect on signal reception. Rain for instance, or snow can interfere. I think what can happen with wind is it blows trees and other foliage around. Trees between the transmitter and your radio will reflect or absorb some of that 800 MHz signal. If that foliage is getting blown around it could cause your signal strength to vary somewhat. But with only 3 miles between you and the nearest transmitter site it's hard to conceive of that ever being an issue. You should have a very solid signal there at all times. Are you certain the signal you're receiving is from just 3 miles away?
As I mentioned, the newer Uniden models, such as the 436 and 536, seem to do a better job with P25. Some have stated the newer Whistler radios also do well. I don't have one of those, so can't comment.
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As I mentioned, the newer Uniden models, such as the 436 and 536, seem to do a better job with P25. Some have stated the newer Whistler radios also do well. I don't have one of those, so can't comment.
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The current firmware for the 996XT is 1.07.03. Looks like that was released in July of 2014. Are you sure that's what your radio is running? It was specifically designed to improve P25 simulcast reception. You can check the firmware version in the Menu under 'Settings'.
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I'm not by the scanner but I believe that was the version. There are trees between me and the tower but it shouldn't be thick woods. The tower is definitely used for emergency responders I'm assuming it broadcasts a signal as is was installed to try to help emergency crew get signal in the buildings in town
Well, it just seems odd. If the transmitter is only 3 miles from your house you should be getting a very solid signal, even if there are some trees and a bit of a hill in the way. Have you tried putting the radio in your car, plugging it into the cigarette lighter, and driving around? If you drive to the top of the hill between you and the transmitter does the signal improve significantly? If not, then maybe your problem is just a weak signal from a more distant transmitter. In that scenario a Yagi almost certainly would help. The more things you try, the more you will learn, and eventually you will find a solution.
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