[BC] Nautel 2 Armstrong

[Robert Meuser]

Scott:

BIG mistake. Do not set your clip level more than 94% worst case. 92% is 
a safe point.

R


Bailey, Scott wrote:

>These surges sound like a phone company problems.  I have argued with
>BellSouth (now AT&T) over this. I have surges coming from BellSouth,
>blowing parts on my Comrex box we use to take an audio feed from Metro
>Networks in Nashville.
>
>The one thing I want to know is how to get to the negative clipper, with
>out removing the transmitter from the rack. We have the clipping set at
>the factory setting at 90%. I would like to bring it up to 99%. Did you
>have the factory do this, or did you do this yourself?
>
>My studio is with the transmitter, so I don't have to have a phone line
>or STL.
>
>Just out of curiosity, what station(s) you have running the X-1000B?
>
>Scott Bailey
>Owner/Operator
>WMRO-AM
>
>-----Original Message-----
>From: broadcast-bounces at radiolists.net
>[mailto:broadcast-bounces at radiolists.net] On Behalf Of Robert Bowe
>Sent: Wednesday, February 07, 2007 10:38 AM
>To: Broadcasters' Mailing List
>Subject: Re: [BC] Nautel 2 Armstrong
>
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>The circuit in question was the 8k loop.  The surge would somehow get
>past the 9200 and it ended up blowing the Mod FET on the RF AMP board
>and then the RF final(s) would go before the fuse would let go.  The
>9200 had no problems and after I tied the telco ground to the station
>ground (hey I didn't install it) the system only lost 1 final (a
>leftover, stressed FET) in over a year (with numerous storms - a period
>that would've require numerous rebuilds).  It doesn't make much sense
>but that was the cure.
>
>Our other unit is duplexed with a higher power low band station, it has
>run flawlessly and both of the X-1000B's have received numerous
>complements on the sound and have easily passed their NRSC-2
>measurements.
>
>The mods to the units have been to set the negative clipper to 98% (up
>from 90%), set the positive to 125%, and add a circuit to turn off the
>ON LED when the HV fuse fails.
>
>I did forward the errors that I found on the prints to Sinan (the main
>error is in the HV section of the RF boards - the parts are in the wrong
>order and it is pretty obvious when you look at it - I don't have a
>print in front of me so I don't have the details).
>
>
>Bailey, Scott wrote:
>  
>
>>I've ran mine through a many of storms WITH NO FIAIURE.  I didn't know
>>about the schematic error, due to we really have had no need to look
>>    
>>
>at
>  
>
>>them. Robert, I hope you brought this to Sinan's attention. 
>>
>>I am sort of confused; did your phone system grounding have something
>>    
>>
>to
>  
>
>>do with your remote control, instead of the transmitter?
>>
>>Scott
>>
>>    
>>
>
>
>- --
>
>Robert Bowe, CSRE
>Director of Engineering
>MBC Grand Broadcasting
>Grand Junction, CO
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