[Fwd: Re: [CQ-Contest] Anyone ever set up near a Cell Phone Tower?]

[Dan Weisenburger]

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Hi every one,

Steve's experiance has obviously been a good one, however, although the 
bucks are nice there can be several drawbacks.  After reading some of the 
other comments I thought there needed to be some information shared.

As always,  "Your milage may vary" applies in a case like this.


Dan

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Message-ID: <33293F57.238E at erols.com>
Date: Fri, 14 Mar 1997 04:06:47 -0800
From: Dan Weisenburger <kw4t at erols.com>
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To: Larry Reader <readerl at goliath.sunyocc.edu>
Subject: Re: [CQ-Contest] Anyone ever set up near a Cell Phone Tower?
References: <9703131406.AA15274 at goliath.sunyocc.edu>
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Hi Larry,

I'm certainly GLAD you asked about Cellular and Contesting.  I'm a Cellular Engineer, 
presently doing Data Performance Engineering (Glorified Paket Radio) for Bell Atlantic 
NYNEX Mobile.  My resume' includes time spent doing cellular engineering work in Latin 
America. There are several issues to be examined.

1.      Not all cellular base stations are created equal. Some manufacturers use        
        extremely noisy, and raspy microprocessors in the base station controllers.     
        What a given Cellular Service Provider uses today could be replaced by a        
        completely different brand tommorrow (i.e. Motorola equipment is replaced by    
        Harris). This is a very common occurance in the Cellular Industry. These are    
        indusrial computing devices and RF Generators.  All Cells that I've seen use a  
        3 to 70 Mhz Master Oscillator and multiple IF's the mixing and multipliers used 
        vary widely.

2.	Most cells have multiple HF Power supplies.  These supplies are industrial      
        strength and can produce incredible amounts of noise.

3.      Good help is hard to find. Cellular companies are often slow to identify        
        degraded "Type N Connectors"  at the antenna jumper or bad antennas which are   
        causing arching even though this can sometimes be heard on an analog phone.
        Many companies add more radios to a site than good engineering practice says is 
        prudent.  Although each radio is rated for 100 to 500 watts ERP (depending upon 
        the type of license and location), the composite power often exceeds that for   
        which the antenna is rated at a busy cell site. Quality antennas are seldom used 
        in Latin America, and just as in Ham Radio, the capabilities of the antennas are 
        often fall short of the claims made in the catalog.  Many Latin American        
        Cellular Companies uses Duplexors to gain channel capacity on a tower,  Most of 
        which cannot handle Composite power levels in excess of 500 watts.  Many        
        companies, even here in the States, overdrive the linear amplifier circuits into 
        non-linearity.  This wipes out the UHF bands for EME or TE.

4.      The typical shelter is made of fiberglass/frame construction or concrete.  Some 
        are bullet resistant.  Special effort must be made such as adding a screen room 
        when the site is placed in a high ambient RF Field such as a strong local       
        broadcast station. This is mostly done to assure proper operation of calibrated 
        test equipment which is brought into the site.  It is not done to protect a Ham 
        Radio Station.

5.	Many Cellular Towers are not properly grounded, present numerous ground loops,  
        and often have additional, unterminated wires placed for future	use which may be 
        noise radiators on some frequencies.  In addition, properly grounded towers do  
        take lightning strikes rather well and disipate the lightning into the ground.  
        Will it get into the ham ground?   Some Cellular companies place corona         
        discharge devices on their towers which can possibly wipe out the 160 and 80    
        meter bands (especially the weaker signals).

.              
I could go on and on but bandwidth and time (mostly time) precludes it.  The short 
answer is:  DON'T DO IT!


See you in two weeks in the WPX,  I'll be pluggin away on 40 with my 100 watts ERP

If I ever don't work you guys in a contest I'll know that the tower went up.

73 from Lake Moneysgone,  Dan,  KW4T

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