[BC] Nautel 2 Armstrong

[Bailey, Scott]

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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