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wirelessdog
join:2008-07-15
Queen Anne, MD

wirelessdog to Jim_in_VA

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Re: 900 ..what causes the interference

»WISP Forum README

Forum regulars run WISPs ranging from a few to several thousand customers. These people are a valuable resource and are to be treated with respect. If you ask a question and receive an answer, be grateful that someone took their time out from a busy schedule to try and help you, even if it was not the answer you were looking for. If you have patience, you can get the answers you need.
jakkwb
join:2009-04-27
Arkansas

jakkwb to Jim_in_VA

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In my area, trains cause 900 interference. I have a 6 radio Canopy tower. When the train goes by my customers that live close to the tracks get 2 of the 3 900 usable channels hosed...Had to work around it...railroad said it COULD NOT BE CHANGED. End of story.

DaDawgs
Premium Member
join:2010-08-02
Deltaville, VA

2 recommendations

DaDawgs to Jim_in_VA

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I think I understand 900 MHz in your area Jim. Shoot the 900 MHz Canopy radios I put up five years ago are still serving customers as if someone might have intended to do it. Talk to the people on the island.

You don't suppose that your ISP just does not GROK 900 MHz where you live? Maybe he is pulling at straws because he really has no clue what is actually happening in the 900 MHz spectrum?

He uses it but he has no clue what is actually there, so let me cut to the chase so you know and can tell him.

Verizon has a 900 MHz PtP network which carries/duplicates almost all the landline traffic in eastern virginia. If you stop and look at the Verizon COs in this area you will realize that those 18 dBd grids on their towers are 900 MHz. Yes you really can tell by looking...

Now there are peak periods during the day when that system is heavily burdened and since it sits between 910 MHz and 920 MHz it tends to impact lower powered WISPs very heavily. What does this mean? Well it means that the WISP actually has to have a clue about RF and link design. If he doesn't, if he is just a great salesman and has no clue about RF implementation ... you get the results you are observing.

And Jim, I'm sorry but that is your reality.
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

54067323 (banned)

Member

said by DaDawgs:

Well it means that the WISP actually has to have a clue about RF and link design. If he doesn't, if he is just a great salesman and has no clue about RF implementation ... you get the results you are observing.

And Jim, I'm sorry but that is your reality.

So much for my AMR idea, but thanks for cutting to core of this interference...
Jim_in_VA (banned)
join:2004-07-11
Cobbs Creek, VA

Jim_in_VA (banned) to DaDawgs

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thanks for that Dawgs. Thought VZ used 800 and 700 here for voice and LTE
wirelessdog
join:2008-07-15
Queen Anne, MD

wirelessdog to Jim_in_VA

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said by Jim_in_VA:

Thought VZ used 800 and 700 here for voice and LTE

For the cellular network. Mike is referring to the Landline network. We see this in remote areas like Elliott's Island, Smith Island and Tangier Island.

Which is why I was dead on when I told you what the real problem is and that is they let their RF engineer aka Mike aka DaDawgs go.

The simplistic approach may be to see if he's willing to use the lower end of the 900mhz spectrum... That, however, without proper planning, may just increase the problems. Crapshoot.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful to DaDawgs

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said by DaDawgs:

Verizon has a 900 MHz PtP network which carries/duplicates almost all the landline traffic in eastern virginia.

... 18 dBd grids between 910 MHz and 920 MHz ...

Verizon EIRP is 30dBm or do they have an exception? I am really curious to see such a beast - any photos of them on a tower?

Anyway, if all such PtP grid antenna positions are known, the WISP could work around them.
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

54067323 (banned) to wirelessdog

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said by wirelessdog:

Mike is referring to the Landline network. We see this in remote areas like Elliott's Island, Smith Island and Tangier Island.

I wonder if that is Radio Pair Gain (RPG), if so then it uses channels as time slots with each customer going off hook being assigned a channel and as traffic increases the number of active channels increases until the system hits capacity at which point any additional attempts to connect are met with a reorder busy signal.

I have seen a lot of RPG in the 451mHz spectrum but it doesn’t surprise me that it would also be used at 900 as well.
wirelessdog
join:2008-07-15
Queen Anne, MD

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These systems were installed many years ago when 900mhz was mostly unused. The grids are huge.

Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak to lutful

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»www.streakwave.com/Itemd ··· GD9%2D18

The local solar panel field installed here used these, I know of 3, pictures upon request. They connected it to a FHSS-RS232 radio.
Not sure they knew they were dropping that in the center of a few 900mhz antennas I have all over the area, they called ..
Jim_in_VA (banned)
join:2004-07-11
Cobbs Creek, VA

Jim_in_VA (banned) to wirelessdog

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Mike did not work for this particular WISP, it was another one in the area. Though it would be a good move to hire him as a consultant. Michael knows his RF

DaDawgs
Premium Member
join:2010-08-02
Deltaville, VA

DaDawgs to wirelessdog

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Dude! They did not let me go. I never worked for them. =)
DaDawgs

DaDawgs to lutful

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Yes I understand and if you really want pictures I can get them for you.
DaDawgs

DaDawgs to 54067323

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That describes what I have seen with my scanner. Transmit is on one channel and receive is on another. It is all between 910 and 920 and yes it fills up during the day as peak periods occur.
DaDawgs

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Thank you sir, and I would be interested... but I think that is unlikely.