republican-creole
Search:  

 
 
   All ForumsHot TopicsGallery






how-to block ads


 
Forums » Industry Forums » Wireless Service Providers » Min Distance from VHF Antenna
Search Topic:
Uniqs:
446
Share Topic:
RSS topic:
toggle:
flat / full
normal / watch
Posting:
Post a:
Post a:
Urgent help with Tsunami »
« Monitoring Wireless Networks  
AuthorAll Replies

keefe007
Premium
join:2004-02-24
Germantown, WI
Min Distance from VHF Antenna

What's the minimum separation I should have between a 2.4 cluster and a 150 Mhz VHF antenna? Can they be in the same plane?


AMD Phreak
Premium
join:2003-12-14
Go as far as you can, but more importantly run STP to the radios, that is if they are on the tower. Overall, it shouldnt be affected, I have experience with stuff being next to VHF, UHF, and high-power 900MHz paging and have not had any issues.

keefe007
Premium
join:2004-02-24
Germantown, WI

How close have you mounted to VHF? The problem is that this antenna is near 15/20 feet tall so it's hard to avoid. It is one of those whip antennas with little ears hanging off. I would be mounting 3 120 degree 2.4 sector antennas on a pole roughly 1.5 feet horizontally away from it.


sporkme
drop the crantini and move it, sister
Premium,MVM
join:2000-07-01
Morristown, NJ
·Optimum Online

reply to AMD Phreak
said by AMD Phreak See Profile :

Go as far as you can, but more importantly run STP to the radios, that is if they are on the tower.
Curious, what's the spectrum that ethernet uses (100MB FE)? Any harmonics from nearby transmitters to look out for (meaning, do any "common" VHF bands perhaps disrupt ethernet with one of their harmonics)?


AMD Phreak
Premium
join:2003-12-14

reply to keefe007
I think isnt it like 100MHz?

Personally I dont chance it. I use STP for all tower installs due to the fact of there is so much RF where our gear is.

The big sticks are hard to get away from. You just have to do your best. I can check with the RF engineer and see what he thinks, in the AM. It shouldnt be all too bad though. I have put some 4.9GHz equipment next (4' above) to a high power 900MHz transmitter (500 or some watts) and didnt have a problem
--
Using a non-ports-system OS is like masturbating with a cheese grater


"No job is so important, and no service is so urgent that we cannot take the time to do it safely."
-- AT&T

lutful
Premium
join:2005-06-16
Ottawa, ON

reply to sporkme
said by sporkme See Profile :

Curious, what's the spectrum that ethernet uses (100MB FE)?
Fast Ethernet transmission uses 125Mbps "raw" data rate which is carried in a 62.5Mhz "MLT-3" waveform.

There is not much VHF coming out of properly twisted portions of the cable - most noise is coupled in the small untwisted section near the connectors.

wispman

join:2004-12-21
USA
reply to sporkme
One time I had an ethernet cable I put in at an install that ran across a desk and it went right by a police scanner. The scanner "keyed up" and was locked on something like 150-160mhz.


sporkme
drop the crantini and move it, sister
Premium,MVM
join:2000-07-01
Morristown, NJ
·Optimum Online

reply to lutful
said by lutful See Profile :

said by sporkme See Profile :

Curious, what's the spectrum that ethernet uses (100MB FE)?
Fast Ethernet transmission uses 125Mbps "raw" data rate which is carried in a 62.5Mhz "MLT-3" waveform.
So you're saying that ethernet is centered at 62.5 MHz or goes from "0"-62.5MHz?
said by lutful See Profile :

There is not much VHF coming out of properly twisted portions of the cable - most noise is coupled in the small untwisted section near the connectors.
I was thinking more about RF from other sources getting into the ethernet cable and providing a hard to diagnose failure or near-failure.

So anything with a strong harmonic that lands somewhere below 100MHz could be bad news, right? Technically, ethernet is RF, correct?

lutful
Premium
join:2005-06-16
Ottawa, ON

Here are various Ethernet baseband spectrum. Properly twisted CAT5 cable has 50-100dB VHF rejection.
Forums » Industry Forums » Wireless Service ProvidersUrgent help with Tsunami »
« Monitoring Wireless Networks  


Sunday, 05-Jul 11:03:21 Terms of Use | Privacy Policy | Hosting by www.nac.net - DSL,Hosting & Co-lo | feedback | contact
over 9.5 years online! © 1999-2009 dslreports.com.republican-creole
page compression OFF
Most commented news this week
· [146] Biden Unveils Broadband Stimulus
· [95] AT&T: 65,000 SMS Sent Per SECOND
· [91] Compuserve Classic Says Goodnight
· [83] Thomas To Appeal Huge RIAA Fines
· [81] Fourth Of July Open Thread
· [79] Obama Using NSA, AT&T For New Snooping Project
· [71] iPhone 3GS Already Jailbroken
· [67] Verizon: Cut Your Landline To Save Money
· [61] Cable Carriers Miss Tru2Way Deadline
· [60] The Pirate Bay Gets Sold
Most people now reading
· TekSavvy Down [TekSavvy]
· 6 firetrucks at 151 [TekSavvy]
· DIR-655 1.31 Firmware available [D-Link]
· "RipIt", a Mac the Ripper alternative [All Things Macintosh]
· [ Professions] Northrend Herbalism and Mining Tracks [World of Warcraft]
· Best free email accounts? [General Questions]
· Maximizing Rogue DPS for 3.1 [World of Warcraft]
· Symantec executive: dangerous to run free antivirus [Security]
· Trojans,spyware,etc...... [Security]
· wasp problemb [Home Repair & Improvement]