[BC] Part 15 radio station

[Broadcast List USER]

COME ON!

It doesn't matter where you excite the radiator.  If you excite a  
2000 foot tower you are exciting a 2000 foot tower, and that is WAY  
outside the rules.

Look at the intent of the rules.

On May 16, 2008, at 6:00 AM, broadcast-request at radiolists.net wrote:

> Message: 18
> Date: Thu, 15 May 2008 19:47:26 -0400
> From: "Craig Healy" <craig.healy at hotmail.com>
> Subject: Re: [BC] Part 15 radio station
> To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
> Message-ID: <BAY112-DAV9A6781941A7CEED8E5E9DE6C90 at phx.gbl>
> Content-Type: text/plain;	charset="Windows-1252"
>
>>> The NRC specifies that ALL antennas mounted outside be properly
>>> grounded...  Thus, the NEC would clearly overrule the FCC part 15  
>>> rules
>>> with regards to a SAFETY ground. The RF ground-now that is quite  
>>> another
>>> matter!
>> ___________
>>
>> A wire from a Part 15 AM tx chassis to a buried ground rod/ 
>> conductor may
> be
>> considered by the user to be a NEC-required safety ground for the  
>> 3-meter
>> antenna, but in reality the antenna is not directly connected to that
>> conductor.  Instead, such a "safety ground" becomes one arm of an
>> off-center-fed dipole, whose lower tip is connected to r-f ground.
>>
>> An expanded-band Part 15 AM system mounted 20 feet above the earth  
>> and
>> using a 20-foot ground conductor produces about 5 times the  
>> groundwave
>> field intensity for the same applied power as when it is mounted  
>> with its
>> base at earth level, with essentially no ground conductor length.   
>> This
>> gain is equivalent to using about 25 times the power with the system
>> mounted at earth level.
>
> How about if the thing is simply bolted to the top of a tower with  
> no ground
> wire at all?  If the guy wires are also conductively connected to  
> the tower,
> they become an elevated radial system.  It would be very hard to  
> say that
> the tower support is only a ground wire.
>
> I can picture one of those things on top of a 2,000' tower.   
> Coverage, I'll
> bet!
>
> Craig Healy
> Providence, RI