[BC] Humming Preamps

[RadioPower Webmaster]

> Date: Sat, 7 Apr 2007 12:57:50 -0400
> From: "Mark Humphrey" <mark3xy at gmail.com>
> Subject: Re: [BC] Humming Preamps
> To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
> Message-ID:
> 	<74b029b80704070957w1bc7dd9bh1796b852fad1143d at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 4/7/07, RadioPower Webmaster <webmaster at radiopower.org> wrote:
>> By the way a
>> Verizon tech had to install inline RF filters to cut the humming and
>> noise from our phone hybrids. I've never met a building this noisy.
>
> Do you know for sure if Verizon installed RF filters, and if so, did
> they make a significant improvement on the phone audio?  If so, then
> it's probably an RF problem.
>
>> From your description "a buzzing sound that seems faster higher
> frequency than 60 cycle hum", I wonder if it's sync buzz from a nearby
> TV transmitter?
>
> Mark

Hi Mark, and everyone else who replied.

yes, we have the misfortune to be located 1/2 mile from the local FOX  
TV and Radio studios with multiple transmitter towers in line of  
sight view. It was digital DSL filters I believe that the Verizon  
tech installed on our service box outside building jumpering between  
the connections of each line. It made a large reduction in the white  
noise and RF signal interference. Thanks to Russ of R&M consulting  
for making the off list suggestion to max all the pre gain settings  
on our various pre-amps and set the master level on 1. This greatly  
reduced the amount of RF white noise and radio signal bleed which by  
the way was 92.9 FM. The mixer and mics are cleaner and have more  
volume before noise. The phono pre-amps which were unusable are now  
much better. It's not as good as it could be, but this little trick  
has at least made it OK for broadcast purposes. I will need to figure  
out better solutions for our music recording studio as that needs to  
be cleaner and better shielded with higher gain for guitar and drums  
than the broadcast studio which is just line or talking mic level. We  
also have another issue with our computer monitors which flicker and  
shake on any refresh rate below or above 85hz. I'm not an engineer  
but those two pieces of info seem relevant?

Shelby