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Author Topic: The Matrix Coms thread  (Read 11464 times)

Justice C. Bigler

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Re: The Matrix Coms thread
« Reply #10 on: March 25, 2011, 03:26:11 pm »

What do you think the expected life is for a digital matrix system? If I put one in this year, with new cabling can I expect it to last for the next 10 to 15 years? Will the RF landscape in 15 years be compatible with current technology for that long?

Also, what should I expect for regular maintenance during that time to keep the system alive and running? Do I need to stock spare I/O cards?
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Mac Kerr

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Useful life of electronic systems
« Reply #11 on: March 25, 2011, 03:37:22 pm »

What do you think the expected life is for a digital matrix system? If I put one in this year, with new cabling can I expect it to last for the next 10 to 15 years? Will the RF landscape in 15 years be compatible with current technology for that long?

Also, what should I expect for regular maintenance during that time to keep the system alive and running? Do I need to stock spare I/O cards?

In a permanent install I would expect the useful life of the electronics to be at least 10 years. If the install is done in a manner that protects the cards from constant plugging and unplugging at the card there should be no reason for anything to fail other than bad luck. As with any technological product only the market and tech developments will determine if the fact that it still operates in 10 years means it is still useful. AFAIK the failure rate on systems where the cards are not moved around, and connections are not made and unmade right on the backplane is very low.

The RF landscape will change over 10 years. Whether or not our so called "white space" situation changes there will be more and more data in the air, and there are likely to be more and more wireless mics, and wireless comm. We are going to have to learn to deal with it, or learn to use wired systems.

Mac
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Henry Cohen

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Re: The Matrix Coms thread
« Reply #12 on: March 25, 2011, 06:09:21 pm »

Will the RF landscape in 15 years be compatible with current technology for that long?
Depends on which part of the spectrum you're referring to: The core VHF and UHF-TV bands will see major changes in permitted services and reallocation in ten years. 900MHz and 2.4GHz will be pretty much the same only more congested, though hopefully devices will be getting more spectrially efficient. 1.9GHz unlicensed PCS (where CC CellCom and Riedel Acrobat operate) has no changes being discussed thus is likely a safe bet for the next ten years (but for Sprint's ugly out of band emissions where they have PCS block A).
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Henry Cohen

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Justice C. Bigler

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Re: The Matrix Coms thread
« Reply #13 on: March 30, 2011, 02:41:06 pm »

1.9GHz unlicensed PCS (where CC CellCom and Riedel Acrobat operate) has no changes being discussed thus is likely a safe bet for the next ten years (but for Sprint's ugly out of band emissions where they have PCS block A).

Henry, how do I found out whether Spring has a PCS tower close by? And what constitutes to close for comfort?
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Henry Cohen

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Re: The Matrix Coms thread
« Reply #14 on: March 30, 2011, 03:52:57 pm »

1.9GHz unlicensed PCS (where CC CellCom and Riedel Acrobat operate) has no changes being discussed thus is likely a safe bet for the next ten years (but for Sprint's ugly out of band emissions where they have PCS block A).

Henry, how do I found out whether Spring has a PCS tower close by? And what constitutes to close for comfort?

To find who has PCS block A in your area, go to the FCC Media Bureau Database, geographic search. Then:
- Select Address and enter your zip code with a radius of 8km;
- Select Frequency Range and enter "1931" [to] "1944".

If the results return more than one licensee, click on each licensee's call sign, then click on the "location" tab and look at the cities listed for the closest location.

The only way to remotely know if the spectrum will be favorable to a 1.9GHz com system is to look at it with a spectrum analyzer. Determine the noise floor and monitor the spectrum (1.920 - 1.93GHz) using peak hold for about 5 minutes in and around the intended coverage area(s). Certainly any aggregate noise floor above -65dBm will be problematic; a lower noise floor will translate into how far the beltpack will effectively operate from the transciever/antenna.
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Henry Cohen

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Justice C. Bigler

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Re: The Matrix Coms thread
« Reply #15 on: March 30, 2011, 03:59:28 pm »

The only way to remotely know if the spectrum will be favorable to a 1.9GHz com system is to look at it with a spectrum analyzer.

What antenna do you recommend to measure that part of the radio spectrum? We have the TTi PSA2701 spectrum analyzer and the Sennheiser A2003 UHF antennas.
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Justice C. Bigler

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Re: The Matrix Coms thread
« Reply #16 on: March 30, 2011, 04:20:38 pm »

It appears as though the PCS Block A is owned by Cingular/AT&T. They were the only result returned in the search.

When I search the range of 1880MHz to 1930MHz (the range listed in Riedel's Acrobat literature as their operating frequency, I get many more results, but it appears as though Sprint and Nextel have the PCS B and G blocks.

Does that bode well for us?

(searching under zip code 74103)
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Mac Kerr

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Re: The Matrix Coms thread
« Reply #17 on: March 30, 2011, 05:19:04 pm »

Henry, how do I found out whether Spring has a PCS tower close by? And what constitutes to close for comfort?

To find who has PCS block A in your area, go to the FCC Media Bureau Database, geographic search. Then:
- Select Address and enter your zip code with a radius of 8km;
- Select Frequency Range and enter "1931" [to] "1944".

If the results return more than one licensee, click on each licensee's call sign, then click on the "location" tab and look at the cities listed for the closest location.

The only way to remotely know if the spectrum will be favorable to a 1.9GHz com system is to look at it with a spectrum analyzer. Determine the noise floor and monitor the spectrum (1.920 - 1.93GHz) using peak hold for about 5 minutes in and around the intended coverage area(s). Certainly any aggregate noise floor above -65dBm will be problematic; a lower noise floor will translate into how far the beltpack will effectively operate from the transciever/antenna.

If Cingular (AT&T) is the license holder, is that a good sign? The license is for "CW-PCS Broadband". The city is Tulsa, where Justice's PAC is.

Mac
« Last Edit: March 30, 2011, 05:21:47 pm by Mac Kerr »
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Henry Cohen

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Re: The Matrix Coms thread
« Reply #18 on: March 30, 2011, 05:46:37 pm »

What antenna do you recommend to measure that part of the radio spectrum? We have the TTi PSA2701 spectrum analyzer and the Sennheiser A2003 UHF antennas.
Use the antenna that came with the TTI and orient it vertically. If you got the telescoping one, adjust it so the signal level (noise floor) is greatest; antenna should be fully, or near fully, collapsed.
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Henry Cohen

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Henry Cohen

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Re: The Matrix Coms thread
« Reply #19 on: March 30, 2011, 05:53:47 pm »

It appears as though the PCS Block A is owned by Cingular/AT&T. They were the only result returned in the search.

When I search the range of 1880MHz to 1930MHz (the range listed in Riedel's Acrobat literature as their operating frequency, I get many more results, but it appears as though Sprint and Nextel have the PCS B and G blocks.

Does that bode well for us?

(searching under zip code 74103)

The Riedel spec of 1880-1930MHz is for Europe, not the US. In the US it operates only in the unlicensed PCS block, 1920-1930MHz. The problem is when Sprint/Nextel has PCS block A (1850-1865MHz uplink / 1930-1945MHz downlink): their downlink (1930-1945MHz, tower transmit to subscriber unit) is adjacent to the unlicensed block and their out of band emissions range from bad to horrendous due to lack of proper filtering. It sounds like AT&T has block A and their OOBE are better, so it bodes well for you. But do test first.
« Last Edit: March 30, 2011, 05:55:53 pm by Henry Cohen »
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Henry Cohen

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Re: The Matrix Coms thread
« Reply #19 on: March 30, 2011, 05:53:47 pm »


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