Outdoor rooftop antenna picking up analog but sucks at getting digital.

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5Rya

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I have an outdoor rooftop antenna that works great for frequencies using analog. Can hear frequencies about 30 miles away from me. When it comes to receiving frequencies that are using P25 I can't even receive the P25 frequencies that have towers 10 miles away from me. Could this be because of water in the cable? When I installed the antenna I wasn't thinking about everything such as water getting the cable. Had the antenna for more than 1.5 years and didn't even think about it as analog works great. Now more and more cities are getting P25 and so I went to buy a P25 scanner (HP1) and the antenna picks up the signal but it is very skippy and has high error rates. Sometimes it is clear enough to hear what they are saying but most times I hear like the first word before it just gives high error rates. I could be very wrong but if the cable had water damage wouldn't the analog signals come in very bad too? Thanks
 

W8RMH

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I doubt it is your antenna. P25 systems are designed to be received within their area of operation. Reception outside of this area can be difficult if not impossible. They don't have the extended range and clarity as the analog and conventional systems did. There may also be issues with Simulcast, Multi-Path Distortion which makes reception, even locally, difficult.

I have to use a Yagi directional antenna to clearly receive my local system 7 miles away over flat terrain.
 
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SteveC0625

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I have an outdoor rooftop antenna that works great for frequencies using analog. Can hear frequencies about 30 miles away from me. When it comes to receiving frequencies that are using P25 I can't even receive the P25 frequencies that have towers 10 miles away from me. Could this be because of water in the cable? When I installed the antenna I wasn't thinking about everything such as water getting the cable. Had the antenna for more than 1.5 years and didn't even think about it as analog works great. Now more and more cities are getting P25 and so I went to buy a P25 scanner (HP1) and the antenna picks up the signal but it is very skippy and has high error rates. Sometimes it is clear enough to hear what they are saying but most times I hear like the first word before it just gives high error rates. I could be very wrong but if the cable had water damage wouldn't the analog signals come in very bad too? Thanks
If there's water in the cable, it would not be selective in its poor performance. It would work equally poorly on any reception. Water doesn't distinguish emission types.
 

5Rya

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I doubt it is your antenna. P25 systems are designed to be received within their area of operation. Reception outside of this area can be difficult if not impossible. They don't have the extended range and clarity as the analog and conventional systems did. There may also be issues with Simulcast, Multi-Path Distortion which makes reception, even locally, difficult.

I have to use a Yagi directional antenna to clearly receive my local system 7 miles away over flat terrain.
The P25 frequency I am trying to monitor is a county wide P25 frequency with towers all over the county. There are about 3 that each are about 10 miles away from me in different directions. If it is a countywide frequency I would assume that they would have it so that it would be heard over the whole county. For reference I am trying to get ESU ch 4. which is on 424.15 and has towers for that frequency on the following 3 licenses.
WQKP779 (ERIE, COUNTY OF) FCC Callsign Details
WNKN564 (ERIE, COUNTY OF) FCC Callsign Details
WQKP997 (ERIE, COUNTY OF) FCC Callsign Details
 

mass-man

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It's called simulcast issues. Your getting signals from maybe all 3 towers at the same time and the signals are interfering with each other! Dig around RR and you'll find many posts about it!

In a nutshell, pick a tower that has the stuff you want to hear...point a yagi at it, blanking out the other signals and you'll be closer to good reception
 

5Rya

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If there's water in the cable, it would not be selective in its poor performance. It would work equally poorly on any reception. Water doesn't distinguish emission types.
Is there anything else that could be wrong with the antenna and/or cable that would cause P25 to act so bad compared to analog. The way it is set up is as follows (Antenna -> N-Male to UHF SO-239 Adapter -> 100 feet of lmr-400 PL-259 -> UHF SO-239 to BNC Male 3ft cable (used to prevent stress on scanner connector port) -> BNC Female to SMA Adapter). Could any of that give me issues?

Also looking at the amazon listing for the lmr-400 it says "Impedance 50 Ohms Frequency Range DC ~ 11 GHz - PL-259 Connectors are not recommended for use above 300Mhz (See N Male options)". The frequency I am trying to get is 424.15. Although I have been receiving tons of analog frequencies in the 400mhz level just fine. I only have issues with frequencies using digital. It's like my antenna hates digital.

Antenna = D130NJ Diamond Super Discone Antenna | Scanner Master
 

5Rya

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It's called simulcast issues. Your getting signals from maybe all 3 towers at the same time and the signals are interfering with each other! Dig around RR and you'll find many posts about it!

In a nutshell, pick a tower that has the stuff you want to hear...point a yagi at it, blanking out the other signals and you'll be closer to good reception
I thought simulcast had to do with P25 Phase 2 systems. This is just a conventional one frequency (424.15) Phase 1 P25. Does simulcast still apply in this case?
 

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It has nothing to do with analog vs. digital. An antenna doesn't care what the emission type is, it cares about frequency and polarization.
Your receiver cares if it's analog or digital.

Just like people that paid extra money for "digital ready" TV antennas....

You've been given some good advice about simulcast issues. Your antenna may be working TOO well.
 

5Rya

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It has nothing to do with analog vs. digital. An antenna doesn't care what the emission type is, it cares about frequency and polarization.
Your receiver cares if it's analog or digital.

Just like people that paid extra money for "digital ready" TV antennas....

You've been given some good advice about simulcast issues. Your antenna may be working TOO well.
So just to confirm, simulcast can happen on Phase 1 Conventional P25 Frequencies. If so, I learned something new today as I always thought it only occurred on Phase 2 P25 Systems.
 

mmckenna

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Simulcast can be done on analog systems too.

-What kind of antenna is it?
-What are you using for coaxial cable?
-What system are you listening to?
 

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I have always get great reception using a Discone Antenna outside my house. I get anywhere from 60-80 miles away with all frequencies. They also work great with UHF-VHF Ham radios for RX and TX.
 

5Rya

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Simulcast can be done on analog systems too.

-What kind of antenna is it?
-What are you using for coaxial cable?
-What system are you listening to?
The way it is set up is as follows (Antenna -> N-Male to UHF SO-239 Adapter -> 100 feet of lmr-400 PL-259 -> UHF SO-239 to BNC Male 3ft cable (used to prevent stress on scanner connector port) -> BNC Female to SMA Adapter). Could any of that give me issues?

Also looking at the amazon listing for the lmr-400 it says "Impedance 50 Ohms Frequency Range DC ~ 11 GHz - PL-259 Connectors are not recommended for use above 300Mhz (See N Male options)". The frequency I am trying to get is 424.15. Although I have been receiving tons of analog frequencies in the 400mhz level just fine. I only have issues with frequencies using digital. It's like my antenna hates digital.

Antenna = D130NJ Diamond Super Discone Antenna | Scanner Master

I am trying to listen to ESU Ch.4 (Erie County, New York (NY) Scanner Frequencies and Radio Frequency Reference). As far as I know the county has 3 different licenses with different towers on each.
WQKP779 (ERIE, COUNTY OF) FCC Callsign Details
WNKN564 (ERIE, COUNTY OF) FCC Callsign Details
WQKP997 (ERIE, COUNTY OF) FCC Callsign Details
 

mmckenna

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Simulcast can be done on analog systems too.

-What kind of antenna is it?
-What are you using for coaxial cable?
-What system are you listening to?
Never mind, I see where you answered those questions.

Simulcast works by transmitting the same signal from different locations on the same frequency. Issue is that you can get in locations where the arrival time of the two signals can effectively cancel each other out. The way to reduce that is to attempt to only receive one transmitter at a time. You can do this with a directional antenna, or maybe even by reducing the gain on your system.
 

mmckenna

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The way it is set up is as follows (Antenna -> N-Male to UHF SO-239 Adapter -> 100 feet of lmr-400 PL-259 -> UHF SO-239 to BNC Male 3ft cable (used to prevent stress on scanner connector port) -> BNC Female to SMA Adapter). Could any of that give me issues?
No. None of that would cause this issue.

Also looking at the amazon listing for the lmr-400 it says "Impedance 50 Ohms Frequency Range DC ~ 11 GHz - PL-259 Connectors are not recommended for use above 300Mhz (See N Male options)". The frequency I am trying to get is 424.15. Although I have been receiving tons of analog frequencies in the 400mhz level just fine. I only have issues with frequencies using digital. It's like my antenna hates digital.
PL-259 connectors are less than ideal at higher frequencies, but in this case it sounds like your antenna is actually working quite well. Don't stress over the connectors. While they do have some more loss and don't provide a perfect 50Ω match, you likely won't be able to notice this with consumer grade gear. You'd need some expensive equipment to quantify the issue.

Antenna = D130NJ Diamond Super Discone Antenna | Scanner Master
Yeah, you're fine.

Like I said above, I think you are receiving both signals well, and that's causing the issue. It's sort of hard to prevent this without swapping out your antenna.

Simulcast can be a real pain in the *** like this.
 

5Rya

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Never mind, I see where you answered those questions.

Simulcast works by transmitting the same signal from different locations on the same frequency. Issue is that you can get in locations where the arrival time of the two signals can effectively cancel each other out. The way to reduce that is to attempt to only receive one transmitter at a time. You can do this with a directional antenna, or maybe even by reducing the gain on your system.
I have a yagi that is currently sitting in storage. Link to the yagi I have is Base Directional Antenna Yagi UHF 450-470 MHz 5 Elements 9.2 dBd, mount, BR6355 | eBay. Only bad thing is that it is for 450-470 and the frequency I need is 424.15. How much of a difference will that make? Also how do I find out the exact direction to put it in when the frequency transmits very rarely?
 

mmckenna

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Won't make much different for receiving.

If you have some spare coax, trying hooking it up temporarily. Try pointing it at one of the towers nearby and see if that helps. You might need to use something like Google Earth to figure out your location and the location of one of the nearby transmitter sites. Google Earth will give you a heading and distance. Use that to point your antenna.

It's entirely possible that the better reception will not come from the closest site. Try several of them and see which one works best.

Having the Yagi will let you experiment.
 

5Rya

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I will probably end up installing the yagi this weekend. Do you know of any good rotors to use with them as I feel it is a need so that I don't have to get on the roof each time to change it especially when it is snowing out. Thanks for the help.
 

5Rya

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Won't make much different for receiving.

If you have some spare coax, trying hooking it up temporarily. Try pointing it at one of the towers nearby and see if that helps. You might need to use something like Google Earth to figure out your location and the location of one of the nearby transmitter sites. Google Earth will give you a heading and distance. Use that to point your antenna.

It's entirely possible that the better reception will not come from the closest site. Try several of them and see which one works best.

Having the Yagi will let you experiment.
I will probably end up installing the yagi this weekend. Do you know of any good rotors to use with them as I feel it is a need so that I don't have to get on the roof each time to change it especially when it is snowing out. Thanks for the help.
 

mmckenna

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Never used a rotor, so no advice to offer. You shouldn't need anything fancy, just a TV antenna rotor would be good enough. Might be worth checking flea markets, etc.

Actually, if you figure out what site works for you, you wouldn't need to rotate the antenna, unless you wanted to see what else you could find. Being where you are, might be interesting to see what you can receive from across the lake.
 

5Rya

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Never used a rotor, so no advice to offer. You shouldn't need anything fancy, just a TV antenna rotor would be good enough. Might be worth checking flea markets, etc.

Actually, if you figure out what site works for you, you wouldn't need to rotate the antenna, unless you wanted to see what else you could find. Being where you are, might be interesting to see what you can receive from across the lake.
Thats what I was thinking, figured if I am going to put it up by not get a rotor so I can see what else I can get.
 
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